/* Copyright (C) 2007 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. In addition to the permissions in the GNU General Public License, the Free Software Foundation gives you unlimited permission to link the compiled version of this file into combinations with other programs, and to distribute those combinations without any restriction coming from the use of this file. (The General Public License restrictions do apply in other respects; for example, they cover modification of the file, and distribution when not linked into a combine executable.) GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING. If not, write to the Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include "bid_internal.h" /***************************************************************************** * BID128_to_int32_rnint ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_rnint, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n < -2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31+1/2 // <=> 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000005, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x500000005ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000005 <=> // C > 0x500000005 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1/2 up) tmp64 = 0x500000005ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31-1/2 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x4fffffffbull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb <=> // C >= 0x4fffffffb * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x4fffffffbull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1/2 < n < 2^31 - 1/2 // Note: some of the cases tested for above fall through to this point if ((q + exp) < 0) { // n = +/-0.0...c(0)c(1)...c(q-1) // return 0 res = 0x00000000; BID_RETURN (res); } else if ((q + exp) == 0) { // n = +/-0.c(0)c(1)...c(q-1) // if 0.c(0)c(1)...c(q-1) <= 0.5 <=> c(0)c(1)...c(q-1) <= 5 * 10^(q-1) // res = 0 // else // res = +/-1 ind = q - 1; if (ind <= 18) { // 0 <= ind <= 18 if ((C1.w[1] == 0) && (C1.w[0] <= midpoint64[ind])) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } else { // 19 <= ind <= 33 if ((C1.w[1] < midpoint128[ind - 19].w[1]) || ((C1.w[1] == midpoint128[ind - 19].w[1]) && (C1.w[0] <= midpoint128[ind - 19].w[0]))) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1/2 <= x <= -1 or 1 <= x < 2^31-1/2 so x can be rounded // to nearest to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even } // else MP in [ODD, EVEN] } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_xrnint ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_xrnint, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n < -2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31+1/2 // <=> 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000005, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x500000005ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000005 <=> // C > 0x500000005 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1/2 up) tmp64 = 0x500000005ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31-1/2 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x4fffffffbull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb <=> // C >= 0x4fffffffb * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x4fffffffbull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1/2 < n < 2^31 - 1/2 // Note: some of the cases tested for above fall through to this point if ((q + exp) < 0) { // n = +/-0.0...c(0)c(1)...c(q-1) // set inexact flag *pfpsf |= INEXACT_EXCEPTION; // return 0 res = 0x00000000; BID_RETURN (res); } else if ((q + exp) == 0) { // n = +/-0.c(0)c(1)...c(q-1) // if 0.c(0)c(1)...c(q-1) <= 0.5 <=> c(0)c(1)...c(q-1) <= 5 * 10^(q-1) // res = 0 // else // res = +/-1 ind = q - 1; if (ind <= 18) { // 0 <= ind <= 18 if ((C1.w[1] == 0) && (C1.w[0] <= midpoint64[ind])) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } else { // 19 <= ind <= 33 if ((C1.w[1] < midpoint128[ind - 19].w[1]) || ((C1.w[1] == midpoint128[ind - 19].w[1]) && (C1.w[0] <= midpoint128[ind - 19].w[0]))) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } // set inexact flag *pfpsf |= INEXACT_EXCEPTION; } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1/2 <= x <= -1 or 1 <= x < 2^31-1/2 so x can be rounded // to nearest to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even } // else MP in [ODD, EVEN] } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_floor ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_floor, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_lt_midpoint = 0; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; int is_midpoint_gt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n < -2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31 // <=> 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000000 <=> // C > 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000 <=> // C >= 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 <= n < 2^31 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // return 0 if (x_sign) res = 0xffffffff; else res = 0x00000000; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31 <= x <= -1 or 1 <= x < 2^31 so x can be rounded // toward negative infinity to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_midpoint_gt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } } // general correction for RM if (x_sign && (is_midpoint_gt_even || is_inexact_lt_midpoint)) { Cstar.w[0] = Cstar.w[0] + 1; } else if (!x_sign && (is_midpoint_lt_even || is_inexact_gt_midpoint)) { Cstar.w[0] = Cstar.w[0] - 1; } else { ; // the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_xfloor ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_xfloor, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_lt_midpoint = 0; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; int is_midpoint_gt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n < -2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31 // <=> 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x500000000 <=> // C > 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000 <=> // C >= 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 <= n < 2^31 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // set inexact flag *pfpsf |= INEXACT_EXCEPTION; // return 0 if (x_sign) res = 0xffffffff; else res = 0x00000000; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31 <= x <= -1 or 1 <= x < 2^31 so x can be rounded // toward negative infinity to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_midpoint_gt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } } // general correction for RM if (x_sign && (is_midpoint_gt_even || is_inexact_lt_midpoint)) { Cstar.w[0] = Cstar.w[0] + 1; } else if (!x_sign && (is_midpoint_lt_even || is_inexact_gt_midpoint)) { Cstar.w[0] = Cstar.w[0] - 1; } else { ; // the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_ceil ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_ceil, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_lt_midpoint = 0; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; int is_midpoint_gt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31-1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x50000000aull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a <=> // C >= 0x50000000a * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1 up) tmp64 = 0x50000000aull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n > 2^31 - 1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31 - 1 // too large if 0.c(0)c(1)...c(q-1) * 10^11 > 0x4fffffff6, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x4fffffff6ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x4fffffff6 <=> // C > 0x4fffffff6 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x4fffffff6ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31-1 < n <= 2^31-1 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // return 0 if (x_sign) res = 0x00000000; else res = 0x00000001; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1 < x <= -1 or 1 <= x <= 2^31-1 so x can be rounded // toward positive infinity to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_midpoint_gt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } } // general correction for RM if (x_sign && (is_midpoint_lt_even || is_inexact_gt_midpoint)) { Cstar.w[0] = Cstar.w[0] - 1; } else if (!x_sign && (is_midpoint_gt_even || is_inexact_lt_midpoint)) { Cstar.w[0] = Cstar.w[0] + 1; } else { ; // the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_xceil ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_xceil, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_lt_midpoint = 0; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; int is_midpoint_gt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31-1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x50000000aull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a <=> // C >= 0x50000000a * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1 up) tmp64 = 0x50000000aull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n > 2^31 - 1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) > 2^31 - 1 // too large if 0.c(0)c(1)...c(q-1) * 10^11 > 0x4fffffff6, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 > 0x4fffffff6ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 > 0x4fffffff6 <=> // C > 0x4fffffff6 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31 up) tmp64 = 0x4fffffff6ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] > C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31-1 < n <= 2^31-1 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // set inexact flag *pfpsf |= INEXACT_EXCEPTION; // return 0 if (x_sign) res = 0x00000000; else res = 0x00000001; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1 < x <= -1 or 1 <= x <= 2^31-1 so x can be rounded // toward positive infinity to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_lt_midpoint = 1; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_midpoint_gt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_lt_midpoint = 0; is_inexact_gt_midpoint = 0; } } // general correction for RM if (x_sign && (is_midpoint_lt_even || is_inexact_gt_midpoint)) { Cstar.w[0] = Cstar.w[0] - 1; } else if (!x_sign && (is_midpoint_gt_even || is_inexact_lt_midpoint)) { Cstar.w[0] = Cstar.w[0] + 1; } else { ; // the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_int ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_int, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31 - 1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x50000000aull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a <=> // C >= 0x50000000a * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1 up) tmp64 = 0x50000000aull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000 <=> // C >= 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1 < n < 2^31 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // return 0 res = 0x00000000; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1 < x <= -1 or 1 <= x < 2^31 so x can be rounded // toward zero to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if ((tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0]))) { } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { } // else the result is exact } else { // the result is inexact; f2* <= 1/2 is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_gt_midpoint = 0; } } // general correction for RZ if (is_midpoint_lt_even || is_inexact_gt_midpoint) { Cstar.w[0] = Cstar.w[0] - 1; } else { ; // exact, the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_xint ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_xint, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; int is_inexact_gt_midpoint = 0; int is_midpoint_lt_even = 0; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31 - 1 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x50000000aull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x50000000a <=> // C >= 0x50000000a * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1 up) tmp64 = 0x50000000aull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000000ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000000 <=> // C >= 0x500000000 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x500000000ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1 < n < 2^31 // Note: some of the cases tested for above fall through to this point if ((q + exp) <= 0) { // n = +/-0.0...c(0)c(1)...c(q-1) or n = +/-0.c(0)c(1)...c(q-1) // set inexact flag *pfpsf |= INEXACT_EXCEPTION; // return 0 res = 0x00000000; BID_RETURN (res); } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1 < x <= -1 or 1 <= x < 2^31 so x can be rounded // toward zero to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if (tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; is_inexact_gt_midpoint = 1; } } // if the result was a midpoint it was rounded away from zero, so // it will need a correction // check for midpoints if ((fstar.w[3] == 0) && (fstar.w[2] == 0) && (fstar.w[1] || fstar.w[0]) && (fstar.w[1] < ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] <= ten2mk128trunc[ind - 1].w[0]))) { // the result is a midpoint; round to nearest if (Cstar.w[0] & 0x01) { // Cstar.w[0] is odd; MP in [EVEN, ODD] // if floor(C*) is odd C = floor(C*) - 1; the result >= 1 Cstar.w[0]--; // Cstar.w[0] is now even is_inexact_gt_midpoint = 0; } else { // else MP in [ODD, EVEN] is_midpoint_lt_even = 1; is_inexact_gt_midpoint = 0; } } // general correction for RZ if (is_midpoint_lt_even || is_inexact_gt_midpoint) { Cstar.w[0] = Cstar.w[0] - 1; } else { ; // exact, the result is already correct } if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_rninta ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_rninta, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 P256; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1/2 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000005, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000005ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000005 <=> // C >= 0x500000005 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1/2 up) tmp64 = 0x500000005ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31-1/2 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x4fffffffbull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb <=> // C >= 0x4fffffffb * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x4fffffffbull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1/2 < n < 2^31 - 1/2 // Note: some of the cases tested for above fall through to this point if ((q + exp) < 0) { // n = +/-0.0...c(0)c(1)...c(q-1) // return 0 res = 0x00000000; BID_RETURN (res); } else if ((q + exp) == 0) { // n = +/-0.c(0)c(1)...c(q-1) // if 0.c(0)c(1)...c(q-1) < 0.5 <=> c(0)c(1)...c(q-1) < 5 * 10^(q-1) // res = 0 // else // res = +/-1 ind = q - 1; if (ind <= 18) { // 0 <= ind <= 18 if ((C1.w[1] == 0) && (C1.w[0] < midpoint64[ind])) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } else { // 19 <= ind <= 33 if ((C1.w[1] < midpoint128[ind - 19].w[1]) || ((C1.w[1] == midpoint128[ind - 19].w[1]) && (C1.w[0] < midpoint128[ind - 19].w[0]))) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1/2 < x <= -1 or 1 <= x < 2^31-1/2 so x can be rounded // to nearest-away to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // if the result was a midpoint, it was already rounded away from zero if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; // no need to check for midpoints - already rounded away from zero! } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); } /***************************************************************************** * BID128_to_int32_xrninta ****************************************************************************/ BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE (int, bid128_to_int32_xrninta, x) int res; UINT64 x_sign; UINT64 x_exp; int exp; // unbiased exponent // Note: C1.w[1], C1.w[0] represent x_signif_hi, x_signif_lo (all are UINT64) UINT64 tmp64, tmp64A; BID_UI64DOUBLE tmp1; unsigned int x_nr_bits; int q, ind, shift; UINT128 C1, C; UINT128 Cstar; // C* represents up to 34 decimal digits ~ 113 bits UINT256 fstar; UINT256 P256; // unpack x x_sign = x.w[1] & MASK_SIGN; // 0 for positive, MASK_SIGN for negative x_exp = x.w[1] & MASK_EXP; // biased and shifted left 49 bit positions C1.w[1] = x.w[1] & MASK_COEFF; C1.w[0] = x.w[0]; // check for NaN or Infinity if ((x.w[1] & MASK_SPECIAL) == MASK_SPECIAL) { // x is special if ((x.w[1] & MASK_NAN) == MASK_NAN) { // x is NAN if ((x.w[1] & MASK_SNAN) == MASK_SNAN) { // x is SNAN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is QNaN // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } else { // x is not a NaN, so it must be infinity if (!x_sign) { // x is +inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } else { // x is -inf // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; } BID_RETURN (res); } } // check for non-canonical values (after the check for special values) if ((C1.w[1] > 0x0001ed09bead87c0ull) || (C1.w[1] == 0x0001ed09bead87c0ull && (C1.w[0] > 0x378d8e63ffffffffull)) || ((x.w[1] & 0x6000000000000000ull) == 0x6000000000000000ull)) { res = 0x00000000; BID_RETURN (res); } else if ((C1.w[1] == 0x0ull) && (C1.w[0] == 0x0ull)) { // x is 0 res = 0x00000000; BID_RETURN (res); } else { // x is not special and is not zero // q = nr. of decimal digits in x // determine first the nr. of bits in x if (C1.w[1] == 0) { if (C1.w[0] >= 0x0020000000000000ull) { // x >= 2^53 // split the 64-bit value in two 32-bit halves to avoid rounding errors if (C1.w[0] >= 0x0000000100000000ull) { // x >= 2^32 tmp1.d = (double) (C1.w[0] >> 32); // exact conversion x_nr_bits = 33 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } else { // x < 2^32 tmp1.d = (double) (C1.w[0]); // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // if x < 2^53 tmp1.d = (double) C1.w[0]; // exact conversion x_nr_bits = 1 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } } else { // C1.w[1] != 0 => nr. bits = 64 + nr_bits (C1.w[1]) tmp1.d = (double) C1.w[1]; // exact conversion x_nr_bits = 65 + ((((unsigned int) (tmp1.ui64 >> 52)) & 0x7ff) - 0x3ff); } q = nr_digits[x_nr_bits - 1].digits; if (q == 0) { q = nr_digits[x_nr_bits - 1].digits1; if (C1.w[1] > nr_digits[x_nr_bits - 1].threshold_hi || (C1.w[1] == nr_digits[x_nr_bits - 1].threshold_hi && C1.w[0] >= nr_digits[x_nr_bits - 1].threshold_lo)) q++; } exp = (x_exp >> 49) - 6176; if ((q + exp) > 10) { // x >= 10^10 ~= 2^33.2... (cannot fit in 32 bits) // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } else if ((q + exp) == 10) { // x = c(0)c(1)...c(9).c(10)...c(q-1) // in this case 2^29.89... ~= 10^9 <= x < 10^10 ~= 2^33.2... // so x rounded to an integer may or may not fit in a signed 32-bit int // the cases that do not fit are identified here; the ones that fit // fall through and will be handled with other cases further, // under '1 <= q + exp <= 10' if (x_sign) { // if n < 0 and q + exp = 10 // if n <= -2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31+1/2 // <=> 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000005, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x500000005ull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x500000005 <=> // C >= 0x500000005 * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31+1/2 up) tmp64 = 0x500000005ull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } else { // if n > 0 and q + exp = 10 // if n >= 2^31 - 1/2 then n is too large // too large if c(0)c(1)...c(9).c(10)...c(q-1) >= 2^31-1/2 // too large if 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb, 1<=q<=34 if (q <= 11) { tmp64 = C1.w[0] * ten2k64[11 - q]; // C scaled up to 11-digit int // c(0)c(1)...c(9)c(10) or c(0)c(1)...c(q-1)0...0 (11 digits) if (tmp64 >= 0x4fffffffbull) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } else { // if (q > 11), i.e. 12 <= q <= 34 and so -24 <= exp <= -2 // 0.c(0)c(1)...c(q-1) * 10^11 >= 0x4fffffffb <=> // C >= 0x4fffffffb * 10^(q-11) where 1 <= q - 11 <= 23 // (scale 2^31-1/2 up) tmp64 = 0x4fffffffbull; if (q - 11 <= 19) { // 1 <= q - 11 <= 19; 10^(q-11) requires 64 bits __mul_64x64_to_128MACH (C, tmp64, ten2k64[q - 11]); } else { // 20 <= q - 11 <= 23, and 10^(q-11) requires 128 bits __mul_128x64_to_128 (C, tmp64, ten2k128[q - 31]); } if (C1.w[1] > C.w[1] || (C1.w[1] == C.w[1] && C1.w[0] >= C.w[0])) { // set invalid flag *pfpsf |= INVALID_EXCEPTION; // return Integer Indefinite res = 0x80000000; BID_RETURN (res); } // else cases that can be rounded to a 32-bit int fall through // to '1 <= q + exp <= 10' } } } // n is not too large to be converted to int32: -2^31 - 1/2 < n < 2^31 - 1/2 // Note: some of the cases tested for above fall through to this point if ((q + exp) < 0) { // n = +/-0.0...c(0)c(1)...c(q-1) // set inexact flag *pfpsf |= INEXACT_EXCEPTION; // return 0 res = 0x00000000; BID_RETURN (res); } else if ((q + exp) == 0) { // n = +/-0.c(0)c(1)...c(q-1) // if 0.c(0)c(1)...c(q-1) < 0.5 <=> c(0)c(1)...c(q-1) < 5 * 10^(q-1) // res = 0 // else // res = +/-1 ind = q - 1; if (ind <= 18) { // 0 <= ind <= 18 if ((C1.w[1] == 0) && (C1.w[0] < midpoint64[ind])) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } else { // 19 <= ind <= 33 if ((C1.w[1] < midpoint128[ind - 19].w[1]) || ((C1.w[1] == midpoint128[ind - 19].w[1]) && (C1.w[0] < midpoint128[ind - 19].w[0]))) { res = 0x00000000; // return 0 } else if (x_sign) { // n < 0 res = 0xffffffff; // return -1 } else { // n > 0 res = 0x00000001; // return +1 } } // set inexact flag *pfpsf |= INEXACT_EXCEPTION; } else { // if (1 <= q + exp <= 10, 1 <= q <= 34, -33 <= exp <= 9) // -2^31-1/2 < x <= -1 or 1 <= x < 2^31-1/2 so x can be rounded // to nearest-away to a 32-bit signed integer if (exp < 0) { // 2 <= q <= 34, -33 <= exp <= -1, 1 <= q + exp <= 10 ind = -exp; // 1 <= ind <= 33; ind is a synonym for 'x' // chop off ind digits from the lower part of C1 // C1 = C1 + 1/2 * 10^ind where the result C1 fits in 127 bits tmp64 = C1.w[0]; if (ind <= 19) { C1.w[0] = C1.w[0] + midpoint64[ind - 1]; } else { C1.w[0] = C1.w[0] + midpoint128[ind - 20].w[0]; C1.w[1] = C1.w[1] + midpoint128[ind - 20].w[1]; } if (C1.w[0] < tmp64) C1.w[1]++; // calculate C* and f* // C* is actually floor(C*) in this case // C* and f* need shifting and masking, as shown by // shiftright128[] and maskhigh128[] // 1 <= x <= 33 // kx = 10^(-x) = ten2mk128[ind - 1] // C* = (C1 + 1/2 * 10^x) * 10^(-x) // the approximation of 10^(-x) was rounded up to 118 bits __mul_128x128_to_256 (P256, C1, ten2mk128[ind - 1]); if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[1] = P256.w[3]; Cstar.w[0] = P256.w[2]; fstar.w[3] = 0; fstar.w[2] = P256.w[2] & maskhigh128[ind - 1]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } else { // 22 <= ind - 1 <= 33 Cstar.w[1] = 0; Cstar.w[0] = P256.w[3]; fstar.w[3] = P256.w[3] & maskhigh128[ind - 1]; fstar.w[2] = P256.w[2]; fstar.w[1] = P256.w[1]; fstar.w[0] = P256.w[0]; } // the top Ex bits of 10^(-x) are T* = ten2mk128trunc[ind], e.g. // if x=1, T*=ten2mk128trunc[0]=0x19999999999999999999999999999999 // if (0 < f* < 10^(-x)) then the result is a midpoint // if floor(C*) is even then C* = floor(C*) - logical right // shift; C* has p decimal digits, correct by Prop. 1) // else if floor(C*) is odd C* = floor(C*)-1 (logical right // shift; C* has p decimal digits, correct by Pr. 1) // else // C* = floor(C*) (logical right shift; C has p decimal digits, // correct by Property 1) // n = C* * 10^(e+x) // shift right C* by Ex-128 = shiftright128[ind] shift = shiftright128[ind - 1]; // 0 <= shift <= 102 if (ind - 1 <= 21) { // 0 <= ind - 1 <= 21 Cstar.w[0] = (Cstar.w[0] >> shift) | (Cstar.w[1] << (64 - shift)); // redundant, it will be 0! Cstar.w[1] = (Cstar.w[1] >> shift); } else { // 22 <= ind - 1 <= 33 Cstar.w[0] = (Cstar.w[0] >> (shift - 64)); // 2 <= shift - 64 <= 38 } // if the result was a midpoint, it was already rounded away from zero if (x_sign) res = -Cstar.w[0]; else res = Cstar.w[0]; // determine inexactness of the rounding of C* // if (0 < f* - 1/2 < 10^(-x)) then // the result is exact // else // if (f* - 1/2 > T*) then // the result is inexact if (ind - 1 <= 2) { if (fstar.w[1] > 0x8000000000000000ull || (fstar.w[1] == 0x8000000000000000ull && fstar.w[0] > 0x0ull)) { // f* > 1/2 and the result may be exact tmp64 = fstar.w[1] - 0x8000000000000000ull; // f* - 1/2 if ((tmp64 > ten2mk128trunc[ind - 1].w[1] || (tmp64 == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] >= ten2mk128trunc[ind - 1].w[0]))) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } else if (ind - 1 <= 21) { // if 3 <= ind <= 21 if (fstar.w[3] > 0x0 || (fstar.w[3] == 0x0 && fstar.w[2] > onehalf128[ind - 1]) || (fstar.w[3] == 0x0 && fstar.w[2] == onehalf128[ind - 1] && (fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[2] - onehalf128[ind - 1]; tmp64A = fstar.w[3]; if (tmp64 > fstar.w[2]) tmp64A--; if (tmp64A || tmp64 || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } else { // if 22 <= ind <= 33 if (fstar.w[3] > onehalf128[ind - 1] || (fstar.w[3] == onehalf128[ind - 1] && (fstar.w[2] || fstar.w[1] || fstar.w[0]))) { // f2* > 1/2 and the result may be exact // Calculate f2* - 1/2 tmp64 = fstar.w[3] - onehalf128[ind - 1]; if (tmp64 || fstar.w[2] || fstar.w[1] > ten2mk128trunc[ind - 1].w[1] || (fstar.w[1] == ten2mk128trunc[ind - 1].w[1] && fstar.w[0] > ten2mk128trunc[ind - 1].w[0])) { // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } // else the result is exact } else { // the result is inexact; f2* <= 1/2 // set the inexact flag *pfpsf |= INEXACT_EXCEPTION; } } // no need to check for midpoints - already rounded away from zero! } else if (exp == 0) { // 1 <= q <= 10 // res = +/-C (exact) if (x_sign) res = -C1.w[0]; else res = C1.w[0]; } else { // if (exp > 0) => 1 <= exp <= 9, 1 <= q < 9, 2 <= q + exp <= 10 // res = +/-C * 10^exp (exact) if (x_sign) res = -C1.w[0] * ten2k64[exp]; else res = C1.w[0] * ten2k64[exp]; } } } BID_RETURN (res); }