diff options
Diffstat (limited to 'gcc-4.9/libgcc/config/picochip/udivmodhi4.S')
| -rw-r--r-- | gcc-4.9/libgcc/config/picochip/udivmodhi4.S | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/gcc-4.9/libgcc/config/picochip/udivmodhi4.S b/gcc-4.9/libgcc/config/picochip/udivmodhi4.S new file mode 100644 index 000000000..920eb375a --- /dev/null +++ b/gcc-4.9/libgcc/config/picochip/udivmodhi4.S @@ -0,0 +1,238 @@ +// picoChip ASM file +// +// Support for 16-bit unsigned division/modulus. +// +// Copyright (C) 2003-2014 Free Software Foundation, Inc. +// Contributed by Picochip Ltd. +// Maintained by Daniel Towner (daniel.towner@picochip.com) +// +// 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 3, or (at your option) any +// later version. +// +// 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. +// +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. +// +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +.section .text + +.global __udivmodhi4 +__udivmodhi4: +_picoMark_FUNCTION_BEGIN= + +// picoChip Function Prologue : &__udivmodhi4 = 6 bytes + + // 16-bit unsigned division. The divstep function is only capable of + // handling 15-bit division (plus a sign to give 16-bits). It is not + // capable of handling unsigned division directly. Instead, take + // advantage of the special property that + // ((divisor / 2) / dividend) * 2 will be almost good enough. The + // error in the result is only 0 or 1, and this can be easily + // tested and corrected. A full description of the algorithm can + // be found in `Hacker's Delight', by Henry Warren, page 146. + + // Input: + // r0 - dividend + // r1 - divisor + // Output: + // r0 - quotient + // r1 - remainder + + // Note that the lr, and original inputs are speculatively saved. They + // will only be restored if the 15-bit division function is called. + + sub.0 r1,0,r15 \ stl r[0:1],(fp)-1 + bge divisorIs15bit +=-> sub.0 r0,r1,r2 \ stw lr,(fp)-3 + + // The divisor is >= 2^15. + bhs quotientIs1 + + // The dividend < divisor. The quotient is thus 0, and the + // remainder is the dividend. + copy.0 r0,r1 \ jr (lr) +=-> copy.0 0,r0 + +quotientIs1: + // The dividend >= divisor. The quotient is thus 1, and the + // remainder can be computed directly by subtraction (i.e., the + // result of the comparison already performed to branch here). + jr (lr) \ copy.0 r2,r1 +=-> copy.0 1,r0 + +divisorIs15bit: + // The divisor is < 2^15. + + // Divide the original dividend by 2, and call the 15-bit division. + // Note that the original dividend is stored in r5, which is + // known to be unused by the called function, so that + // a memory stall isn't introduced immediately after the + // function returns, to reload this value from memory. + + jl (&__divmod15) \ copy.0 r0,r5 // fn_call &__divmod15 +=-> lsr.0 r0,1,r0 + + // Compute the new quotient and remainder by multiplying them by 2. + // The remainder will be 1 out, if the original dividend was odd. + and.0 r5,1,r5 \ ldl (fp)-1,r[2:3] + add.0 [lsl r1,1],r5,r1 \ lsl.1 r0,1,r0 + + // The error in the quotient is 0 or 1. The error can be determined + // by comparing the remainder to the original divisor. If the + // remainder is bigger, then an error of 1 has been introduced. + sub.0 r1,r3,r15 \ ldw (fp)-3,lr + blo noCompensation +=-> nop + add.0 r0,1,r0 \ sub.1 r1,r3,r1 +noCompensation: + jr (lr) + +_picoMark_FUNCTION_END= +// picoChip Function Epilogue : udivmodhi4 + + +//============================================================================ +// All DWARF information between this marker, and the END OF DWARF +// marker should be included in the source file. Search for +// FUNCTION_STACK_SIZE_GOES_HERE and FUNCTION NAME GOES HERE, and +// provide the relevant information. Add markers called +// _picoMark_FUNCTION_BEGIN and _picoMark_FUNCTION_END around the +// function in question. +//============================================================================ + +//============================================================================ +// Frame information. +//============================================================================ + +.section .debug_frame +_picoMark_DebugFrame= + +// Common CIE header. +.unalignedInitLong _picoMark_CieEnd-_picoMark_CieBegin +_picoMark_CieBegin= +.unalignedInitLong 0xffffffff +.initByte 0x1 // CIE Version +.ascii 16#0# // CIE Augmentation +.uleb128 0x1 // CIE Code Alignment Factor +.sleb128 2 // CIE Data Alignment Factor +.initByte 0xc // CIE RA Column +.initByte 0xc // DW_CFA_def_cfa +.uleb128 0xd +.uleb128 0x0 +.align 2 +_picoMark_CieEnd= + +// FDE +_picoMark_LSFDE0I900821033007563= +.unalignedInitLong _picoMark_FdeEnd-_picoMark_FdeBegin +_picoMark_FdeBegin= +.unalignedInitLong _picoMark_DebugFrame // FDE CIE offset +.unalignedInitWord _picoMark_FUNCTION_BEGIN // FDE initial location +.unalignedInitWord _picoMark_FUNCTION_END-_picoMark_FUNCTION_BEGIN +.initByte 0xe // DW_CFA_def_cfa_offset +.uleb128 0x6 // <-- FUNCTION_STACK_SIZE_GOES_HERE +.initByte 0x4 // DW_CFA_advance_loc4 +.unalignedInitLong _picoMark_FUNCTION_END-_picoMark_FUNCTION_BEGIN +.initByte 0xe // DW_CFA_def_cfa_offset +.uleb128 0x0 +.align 2 +_picoMark_FdeEnd= + +//============================================================================ +// Abbrevation information. +//============================================================================ + +.section .debug_abbrev +_picoMark_ABBREVIATIONS= + +.section .debug_abbrev + .uleb128 0x1 // (abbrev code) + .uleb128 0x11 // (TAG: DW_TAG_compile_unit) + .initByte 0x1 // DW_children_yes + .uleb128 0x10 // (DW_AT_stmt_list) + .uleb128 0x6 // (DW_FORM_data4) + .uleb128 0x12 // (DW_AT_high_pc) + .uleb128 0x1 // (DW_FORM_addr) + .uleb128 0x11 // (DW_AT_low_pc) + .uleb128 0x1 // (DW_FORM_addr) + .uleb128 0x25 // (DW_AT_producer) + .uleb128 0x8 // (DW_FORM_string) + .uleb128 0x13 // (DW_AT_language) + .uleb128 0x5 // (DW_FORM_data2) + .uleb128 0x3 // (DW_AT_name) + .uleb128 0x8 // (DW_FORM_string) +.initByte 0x0 +.initByte 0x0 + + .uleb128 0x2 ;# (abbrev code) + .uleb128 0x2e ;# (TAG: DW_TAG_subprogram) +.initByte 0x0 ;# DW_children_no + .uleb128 0x3 ;# (DW_AT_name) + .uleb128 0x8 ;# (DW_FORM_string) + .uleb128 0x11 ;# (DW_AT_low_pc) + .uleb128 0x1 ;# (DW_FORM_addr) + .uleb128 0x12 ;# (DW_AT_high_pc) + .uleb128 0x1 ;# (DW_FORM_addr) +.initByte 0x0 +.initByte 0x0 + +.initByte 0x0 + +//============================================================================ +// Line information. DwarfLib requires this to be present, but it can +// be empty. +//============================================================================ + +.section .debug_line +_picoMark_LINES= + +//============================================================================ +// Debug Information +//============================================================================ +.section .debug_info + +//Fixed header. +.unalignedInitLong _picoMark_DEBUG_INFO_END-_picoMark_DEBUG_INFO_BEGIN +_picoMark_DEBUG_INFO_BEGIN= +.unalignedInitWord 0x2 +.unalignedInitLong _picoMark_ABBREVIATIONS +.initByte 0x2 + +// Compile unit information. +.uleb128 0x1 // (DIE 0xb) DW_TAG_compile_unit) +.unalignedInitLong _picoMark_LINES +.unalignedInitWord _picoMark_FUNCTION_END +.unalignedInitWord _picoMark_FUNCTION_BEGIN +// Producer is `picoChip' +.ascii 16#70# 16#69# 16#63# 16#6f# 16#43# 16#68# 16#69# 16#70# 16#00# +.unalignedInitWord 0xcafe // ASM language +.ascii 16#0# // Name. DwarfLib expects this to be present. + +.uleb128 0x2 ;# (DIE DW_TAG_subprogram) + +// FUNCTION NAME GOES HERE. Use `echo name | od -t x1' to get the hex. Each hex +// digit is specified using the format 16#XX# +.ascii 16#5f# 16#75# 16#64# 16#69# 16#76# 16#6d# 16#6f# 16#64# 16#68# 16#69# 16#34# 16#0# // Function name `_udivmodhi4' +.unalignedInitWord _picoMark_FUNCTION_BEGIN // DW_AT_low_pc +.unalignedInitWord _picoMark_FUNCTION_END // DW_AT_high_pc + +.initByte 0x0 // end of compile unit children. + +_picoMark_DEBUG_INFO_END= + +//============================================================================ +// END OF DWARF +//============================================================================ +.section .endFile +// End of picoChip ASM file |