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Diffstat (limited to 'gcc-4.2.1/gcc/config/alpha/lib1funcs.asm')
| -rw-r--r-- | gcc-4.2.1/gcc/config/alpha/lib1funcs.asm | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/gcc-4.2.1/gcc/config/alpha/lib1funcs.asm b/gcc-4.2.1/gcc/config/alpha/lib1funcs.asm new file mode 100644 index 000000000..41a551057 --- /dev/null +++ b/gcc-4.2.1/gcc/config/alpha/lib1funcs.asm @@ -0,0 +1,320 @@ +/* DEC Alpha division and remainder support. + Copyright (C) 1994, 1999 Free Software Foundation, Inc. + +This file 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.) + +This file 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 this program; see the file COPYING. If not, write to +the Free Software Foundation, 51 Franklin Street, Fifth Floor, +Boston, MA 02110-1301, USA. */ + +/* This had to be written in assembler because the division functions + use a non-standard calling convention. + + This file provides an implementation of __divqu, __divq, __divlu, + __divl, __remqu, __remq, __remlu and __reml. CPP macros control + the exact operation. + + Operation performed: $27 := $24 o $25, clobber $28, return address to + caller in $23, where o one of the operations. + + The following macros need to be defined: + + SIZE, the number of bits, 32 or 64. + + TYPE, either UNSIGNED or SIGNED + + OPERATION, either DIVISION or REMAINDER + + SPECIAL_CALLING_CONVENTION, 0 or 1. It is useful for debugging to + define this to 0. That removes the `__' prefix to make the function + name not collide with the existing libc.a names, and uses the + standard Alpha procedure calling convention. +*/ + +#ifndef SPECIAL_CALLING_CONVENTION +#define SPECIAL_CALLING_CONVENTION 1 +#endif + +#ifdef L_divl +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __divl +#else +#define FUNCTION_NAME divl +#endif +#define SIZE 32 +#define TYPE SIGNED +#define OPERATION DIVISION +#endif + +#ifdef L_divlu +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __divlu +#else +#define FUNCTION_NAME divlu +#endif +#define SIZE 32 +#define TYPE UNSIGNED +#define OPERATION DIVISION +#endif + +#ifdef L_divq +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __divq +#else +#define FUNCTION_NAME divq +#endif +#define SIZE 64 +#define TYPE SIGNED +#define OPERATION DIVISION +#endif + +#ifdef L_divqu +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __divqu +#else +#define FUNCTION_NAME divqu +#endif +#define SIZE 64 +#define TYPE UNSIGNED +#define OPERATION DIVISION +#endif + +#ifdef L_reml +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __reml +#else +#define FUNCTION_NAME reml +#endif +#define SIZE 32 +#define TYPE SIGNED +#define OPERATION REMAINDER +#endif + +#ifdef L_remlu +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __remlu +#else +#define FUNCTION_NAME remlu +#endif +#define SIZE 32 +#define TYPE UNSIGNED +#define OPERATION REMAINDER +#endif + +#ifdef L_remq +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __remq +#else +#define FUNCTION_NAME remq +#endif +#define SIZE 64 +#define TYPE SIGNED +#define OPERATION REMAINDER +#endif + +#ifdef L_remqu +#if SPECIAL_CALLING_CONVENTION +#define FUNCTION_NAME __remqu +#else +#define FUNCTION_NAME remqu +#endif +#define SIZE 64 +#define TYPE UNSIGNED +#define OPERATION REMAINDER +#endif + +#define tmp0 $3 +#define tmp1 $28 +#define cnt $1 +#define result_sign $2 + +#if SPECIAL_CALLING_CONVENTION +#define N $24 +#define D $25 +#define Q RETREG +#define RETREG $27 +#else +#define N $16 +#define D $17 +#define Q RETREG +#define RETREG $0 +#endif + +/* Misc symbols to make alpha assembler easier to read. */ +#define zero $31 +#define sp $30 + +/* Symbols to make interface nicer. */ +#define UNSIGNED 0 +#define SIGNED 1 +#define DIVISION 0 +#define REMAINDER 1 + + .set noreorder + .set noat +.text + .align 3 + .globl FUNCTION_NAME + .ent FUNCTION_NAME +FUNCTION_NAME: + + .frame $30,0,$26,0 + .prologue 0 + +/* Under the special calling convention, we have to preserve all register + values but $23 and $28. */ +#if SPECIAL_CALLING_CONVENTION + lda sp,-64(sp) +#if OPERATION == DIVISION + stq N,0(sp) +#endif + stq D,8(sp) + stq cnt,16(sp) + stq result_sign,24(sp) + stq tmp0,32(sp) +#endif + +/* If we are computing the remainder, move N to the register that is used + for the return value, and redefine what register is used for N. */ +#if OPERATION == REMAINDER + bis N,N,RETREG +#undef N +#define N RETREG +#endif + +/* Perform conversion from 32 bit types to 64 bit types. */ +#if SIZE == 32 +#if TYPE == SIGNED + /* If there are problems with the signed case, add these instructions. + The caller should already have done this. + addl N,0,N # sign extend N + addl D,0,D # sign extend D + */ +#else /* UNSIGNED */ + zap N,0xf0,N # zero extend N (caller required to sign extend) + zap D,0xf0,D # zero extend D +#endif +#endif + +/* Check for divide by zero. */ + bne D,$34 + lda $16,-2(zero) + call_pal 0xaa +$34: + +#if TYPE == SIGNED +#if OPERATION == DIVISION + xor N,D,result_sign +#else + bis N,N,result_sign +#endif +/* Get the absolute values of N and D. */ + subq zero,N,tmp0 + cmovlt N,tmp0,N + subq zero,D,tmp0 + cmovlt D,tmp0,D +#endif + +/* Compute CNT = ceil(log2(N)) - ceil(log2(D)). This is the number of + divide iterations we will have to perform. Should you wish to optimize + this, check a few bits at a time, preferably using zap/zapnot. Be + careful though, this code runs fast fro the most common cases, when the + quotient is small. */ + bge N,$35 + bis zero,1,cnt + blt D,$40 + .align 3 +$39: addq D,D,D + addl cnt,1,cnt + bge D,$39 + br zero,$40 +$35: cmpult N,D,tmp0 + bis zero,zero,cnt + bne tmp0,$42 + .align 3 +$44: addq D,D,D + cmpult N,D,tmp0 + addl cnt,1,cnt + beq tmp0,$44 +$42: srl D,1,D +$40: + subl cnt,1,cnt + + +/* Actual divide. Could be optimized with unrolling. */ +#if OPERATION == DIVISION + bis zero,zero,Q +#endif + blt cnt,$46 + .align 3 +$49: cmpule D,N,tmp1 + subq N,D,tmp0 + srl D,1,D + subl cnt,1,cnt + cmovne tmp1,tmp0,N +#if OPERATION == DIVISION + addq Q,Q,Q + bis Q,tmp1,Q +#endif + bge cnt,$49 +$46: + + +/* The result is now in RETREG. NOTE! It was written to RETREG using + either N or Q as a synonym! */ + + +/* Change the sign of the result as needed. */ +#if TYPE == SIGNED + subq zero,RETREG,tmp0 + cmovlt result_sign,tmp0,RETREG +#endif + + +/* Restore clobbered registers. */ +#if SPECIAL_CALLING_CONVENTION +#if OPERATION == DIVISION + ldq N,0(sp) +#endif + ldq D,8(sp) + ldq cnt,16(sp) + ldq result_sign,24(sp) + ldq tmp0,32(sp) + + lda sp,64(sp) +#endif + + +/* Sign extend an *unsigned* 32 bit result, as required by the Alpha + conventions. */ +#if TYPE == UNSIGNED && SIZE == 32 + /* This could be avoided by adding some CPP hair to the divide loop. + It is probably not worth the added complexity. */ + addl RETREG,0,RETREG +#endif + + +#if SPECIAL_CALLING_CONVENTION + ret zero,($23),1 +#else + ret zero,($26),1 +#endif + .end FUNCTION_NAME |