94 lines
2.1 KiB
NASM
94 lines
2.1 KiB
NASM
dnl AMD64 mpn_diveby3
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dnl Copyright 2009 Jason Moxham
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dnl This file is part of the MPIR Library.
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dnl The MPIR Library is free software; you can redistribute it and/or modify
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dnl it under the terms of the GNU Lesser General Public License as published
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dnl by the Free Software Foundation; either version 2.1 of the License, or (at
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dnl your option) any later version.
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dnl The MPIR Library is distributed in the hope that it will be useful, but
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dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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dnl License for more details.
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dnl You should have received a copy of the GNU Lesser General Public License
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dnl along with the MPIR Library; see the file COPYING.LIB. If not, write
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dnl to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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dnl Boston, MA 02110-1301, USA.
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include(`../config.m4')
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C (rdi,rdx)=(rsi,rdx) rcx=carry in
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C rax=carry out
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C NOTE could pass 55555...555 as next param so this would
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C be mpn_divexact_by_ff_over_c , and change imul at end , or
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C drop backwards compatibilty and just dump the two imuls
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ASM_START()
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PROLOGUE(mpn_divexact_by3c)
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# Version 1.0.5
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mov $3,%r9d
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lea -24(%rsi,%rdx,8),%rsi
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lea -24(%rdi,%rdx,8),%rdi
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mov $0x5555555555555555,%r8
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imul %r8,%rcx
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sub %rdx,%r9
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jnc skiploop
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ALIGN(16)
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loop:
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mov (%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,(%rdi,%r9,8)
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sbb %rdx,%rcx
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mov 8(%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,8(%rdi,%r9,8)
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sbb %rdx,%rcx
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mov 16(%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,16(%rdi,%r9,8)
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sbb %rdx,%rcx
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mov 24(%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,24(%rdi,%r9,8)
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sbb %rdx,%rcx
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add $4,%r9
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jnc loop
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skiploop:
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# so have 3-r9 limbs left to do
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test $2,%r9
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jnz skip
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mov (%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,(%rdi,%r9,8)
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sbb %rdx,%rcx
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mov 8(%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,8(%rdi,%r9,8)
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sbb %rdx,%rcx
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add $2,%r9
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skip:
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test $1,%r9
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jnz end
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mov (%rsi,%r9,8),%rax
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mul %r8
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sub %rax,%rcx
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mov %rcx,(%rdi,%r9,8)
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sbb %rdx,%rcx
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end:
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#imul $-3,%rcx,%rax
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lea (%rcx,%rcx,2),%rax
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neg %rax
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ret
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EPILOGUE()
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