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// picoChip ASM file
//
// Support for 32-bit unsigned division/modulus.
//
// Copyright (C) 2003, 2004, 2005, 2008, 2009 Free Software Foundation, Inc.
// Contributed by picoChip Designs 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 __udivmodsi4
__udivmodsi4:
_picoMark_FUNCTION_BEGIN=
// picoChip Function Prologue : &__udivmodsi4 = 24 bytes
// Schedule the register saves alongside the special cases, so that
// if the special cases fail, the registers will have already
// been stored onto the stack.
SUB.0 R3,R1,r15 \ STL R[13:12],(FP)-1
BHS skipCommonCase \ STL R[9:8],(FP)-4
=-> SUB.0 R2,1,r15 \ STL R[11:10],(FP)-3
_L2:
// Flags set above, and in _L2 caller.
BNE restOfCode
=-> SUB.0 R3,0,r15
BNE restOfCode
=-> COPY.0 R0,R4 \ COPY.1 R1,R5
JR (R12) // Return to caller
=-> COPY.0 0,R6 \ COPY.1 0,R7
// Never reach here
skipCommonCase:
SUB.0 R3,R1,r15
BNE _L3 // (Reversed branch)
=-> SUB.0 R2,R0,r15 // Must be set in delay slot, so ready by _L9
_L9:
BLO _L2 // (Reversed branch)
=-> SUB.0 R2,1,r15
_L3:
SUB.0 R2,R0,r15
BEQ _L10 // (Reversed branch)
=-> SUB.0 R1,R3,r15 // Set flags for branch at _L10
_L4:
// greater than
COPY.0 0,R4 \ COPY.1 0,R5 \ JR (R12) // Return to caller
=-> COPY.0 R0,R6 \ COPY.1 R1,R7
// Doesn't reach here.
_L10:
// Flags set in _L10 call delay slot.
BNE _L4
=-> COPY.0 1,R4 \ COPY.1 0,R5
JR (R12) // Return to caller
=-> COPY.0 0,R6 \ COPY.1 0,R7
restOfCode:
// Prologue
// Register saves scheduled alongside special cases above.
ADD.0 FP,-20,FP \ STW R14,(FP)-4
// The following can be scheduled together.
// dividend in R[9:8] (from R[1:0])
// divisor in R[7:6] (from R[3:2])
// R14 := clzsi2 (dividend)
// R0 := clzsi2 (divisor)
JL (&__clzsi2) \ COPY.0 R0,R8 \ COPY.1 R1,R9
=-> COPY.0 R2,R6 \ COPY.1 R3,R7
COPY.0 R0,R14 \ JL (&__clzsi2)
=-> COPY.0 R6,R0 \ COPY.1 R7,R1
// R14 := R0 - R14
SUB.0 R0,R14,R14
ADD.0 R14,1,R0 // R0 := R14 + 1 (HI)
// R[11:10] = R[7,6] << R14
SUB.0 15,R14,r15
LSL.0 R6,R14,R11 \ BLT setupDivstepLoop
=-> SUB.0 0,R14,R4 \ COPY.1 0,R10
// Zero shift is a special case. Shifting by zero within a 16-bit
// source object is fine, but don't execute the OR of the right-shift
// into the final result.
LSL.0 R7,R14,R11 \ BEQ setupDivstepLoop
=-> LSL.0 R6,R14,R10
LSR.0 R6,R4,R4
OR.0 R11,R4,R11
setupDivstepLoop:
// R[5:4] := R[9:8] (SI)
COPY.0 R8,R4 \ COPY.1 R9,R5
COPY.0 0,R6 \ COPY.1 R0,R8
// Store original value of loopCount for use after the loop.
// The Subtraction is handled in the tail of the loop iteration
// after this point.
SUB.0 R4,R10,R0 \ COPY.1 R8,R14
// workingResult in R4,5,6
// temps in r0,1,2 and r7
// alignedDivisor in R10,11
// loopCount in r8
// r3, r9 scratch, used for renaming.
loopStart:
// R0 := R4 - zeroExtend (R10) - only need 33-bits (i.e., 48-bits)
SUBB.0 R5,R11,R1 \ LSR.1 R0,15,R3
SUBB.0 R6,0,R2 \ LSR.1 R1,15,R6
// if (carry) goto shiftOnly
SUB.0 R8,1,R8 \ BNE shiftOnly
=-> LSR.0 R4,15,R7 \ LSL.1 R1,1,R9
OR.0 [LSL R0,1],1,R4 \ BNE loopStart
=-> SUB.0 R4,R10,R0 \ OR.1 R9,R3,R5
BRA loopEnd
shiftOnly:
OR.0 [LSL R5,1],R7,R5 \ BNE loopStart \ LSR.1 R5,15,R6
=-> SUB.0 [LSL R4,1],R10,R0 \LSL.1 R4,1,R4
// End of loop
loopEnd:
// Schedule the computation of the upper word after shifting
// alongside the decision over whether to branch, and the register
// restores.
// R10 is filled with a useful constant.
SUB.0 15,r14,r15 \ LDL (FP)4,R[13:12]
SUB.1 0,R14,R1 // Don't set flags!
LSL.0 R6,R1,R3 \ LDL (FP)-4,R[9:8]
BLT remainderHasMoreThan16Bits \ LSR.0 R5,R14,R7 \ COPY.1 -1,R10
=-> LSL.0 R5,R1,R2 \ OR.1 R7,R3,R3
LSR.0 R4,R14,R3 \ COPY.1 R3,R7
BRA epilogue \ LSR.0 -1,R1,R0 \ COPY.1 0,R5
=-> OR.0 R3,R2,R6 \ AND.1 R0,R4,R4
remainderHasMoreThan16Bits:
LSL.0 R10,R14,R1 \ COPY.1 R3,R6
XOR.0 R10,R1,R1 \ COPY.1 0,R7
AND.0 R1,R5,R5
epilogue:
JR (R12) \ LDW (FP)-4,R14
=-> LDL (FP)-3,R[11:10]
_picoMark_FUNCTION_END=
// picoChip Function Epilogue : udivmodsi4
//============================================================================
// 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 relevent 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 0x18 // <-- 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#73# 16#69# 16#34# 16#0# // Function name `_udivmodsi4'
.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
|
