diff options
Diffstat (limited to 'gcc-4.9/libgcc/config/picochip/divmodhi4.S')
| -rw-r--r-- | gcc-4.9/libgcc/config/picochip/divmodhi4.S | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/gcc-4.9/libgcc/config/picochip/divmodhi4.S b/gcc-4.9/libgcc/config/picochip/divmodhi4.S new file mode 100644 index 000000000..55dd71b62 --- /dev/null +++ b/gcc-4.9/libgcc/config/picochip/divmodhi4.S @@ -0,0 +1,246 @@ +// picoChip ASM file +// +// Support for 16-bit signed 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 + +.align 8 +.global __divmodhi4 +__divmodhi4: +_picoMark_FUNCTION_BEGIN= + +// picoChip Function Prologue : &__divmodhi4 = 4 bytes + + // 16-bit signed division. Most of the special cases are dealt + // with by the 15-bit signed division library (e.g., division by + // zero, division by 1, and so on). This wrapper simply inverts + // any negative inputs, calls the 15-bit library, and flips any + // results as necessary. The + // only special cases to be handled here are where either the + // divisor or the dividend are the maximum negative values. + + // Encode r5 with a bit pattern which indicates whether the + // outputs of the division must be negated. The MSB will be set + // to the sign of the dividend (which controls the remainder's + // sign), while the LSB will store the XOR of the two signs, + // which indicates the quotient's sign. R5 is not modified by the + // 15-bit divmod routine. + sub.0 r1,16#8000#,r15 \ asr.1 r0,15,r4 + beq divisorIsLargestNegative \ lsr.0 r1,15,r3 +=-> sub.0 r0,16#8000#,r15 \ xor.1 r3,r4,r5 + + // Handle least negative dividend with a special case. Note that the + // absolute value of the divisor is also computed here. + add.0 [asr r1,15],r1,r3 \ beq dividendIsLargestNegative +=-> xor.0 [asr r1,15],r3,r1 \ stw lr,(fp)-1 + + // Compute the absolute value of the dividend, and call the main + // divide routine. + add.0 r4,r0,r2 \ jl (&__divmod15) // fn_call &__divmod15 +=-> xor.0 r4,r2,r0 + +handleNegatedResults: + // Speculatively store the negation of the results. + sub.0 0,r0,r2 \ sub.1 0,r1,r3 + + // Does the quotient need negating? The LSB indicates this. + and.0 r5,1,r15 \ ldw (fp)-1,lr + copyne r2,r0 + + asr.0 r5,15,r15 \ jr (lr) +=-> copyne r3,r1 + +dividendIsLargestNegative: + + // Divide the constant -32768. Use the Hacker's Delight + // algorithm (i.e., ((dividend / 2) / divisor) * 2) gives + // approximate answer). This code is a special case, so no + // great effort is made to make it fast, only to make it + // small. + + lsr.0 r0,1,r0 \ jl (&__divmod15) // fn_call &__divmod15 +=-> stw r1,(fp)-2 + + // Load the original divisor, and compute the new quotient and + // remainder. + lsl.0 r0,1,r0 \ ldw (fp)-2,r3 + lsl.0 r1,1,r1 // Fill stall slot + + // 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, + // which must be fixed. + sub.0 r1,r3,r15 + blo noCompensationForError +=-> nop + add.0 r0,1,r0 \ sub.1 r1,r3,r1 +noCompensationForError: + bra handleNegatedResults +=-> nop + +divisorIsLargestNegative: + // The flags indicate whether the dividend is also the maximum negative + copy.0 r0,r1 \ copy.1 0,r0 + copyeq r0,r1 \ jr (lr) +=-> copyeq 1,r0 + +_picoMark_FUNCTION_END= +// picoChip Function Epilogue : __divmodhi4 + + +//============================================================================ +// 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 0x4 // <-- 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#64# 16#69# 16#76# 16#6d# 16#6f# 16#64# 16#68# 16#69# 16#34# 16#0# // Function name `_divmodhi4' +.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 |