hamdist.asm
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上传日期:2022-08-06
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- dnl Intel P5 mpn_hamdist -- mpn hamming distance.
- dnl Copyright 2001, 2002 Free Software Foundation, Inc.
- dnl
- dnl This file is part of the GNU MP Library.
- dnl
- dnl The GNU MP Library is free software; you can redistribute it and/or
- dnl modify it under the terms of the GNU Lesser General Public License as
- dnl published by the Free Software Foundation; either version 3 of the
- dnl License, or (at your option) any later version.
- dnl
- dnl The GNU MP Library is distributed in the hope that it will be useful,
- dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
- dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- dnl Lesser General Public License for more details.
- dnl
- dnl You should have received a copy of the GNU Lesser General Public License
- dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
- include(`../config.m4')
- C P5: 14.0 cycles/limb
- C unsigned long mpn_hamdist (mp_srcptr src1, mp_srcptr src2, mp_size_t size);
- C
- C It might be possible to shave 1 cycle from the loop, and hence 2
- C cycles/limb. The xorb is taking 2 cycles, but a separate load and xor
- C would be 1, if the right schedule could be found (not found so far).
- C Wanting to avoid potential cache bank clashes makes it tricky.
- C The slightly strange quoting here helps the renaming done by tune/many.pl.
- deflit(TABLE_NAME,
- m4_assert_defined(`GSYM_PREFIX')
- GSYM_PREFIX`'mpn_popcount``'_table')
- defframe(PARAM_SIZE,12)
- defframe(PARAM_SRC2, 8)
- defframe(PARAM_SRC1, 4)
- TEXT
- ALIGN(8)
- PROLOGUE(mpn_hamdist)
- deflit(`FRAME',0)
- movl PARAM_SIZE, %ecx
- pushl %esi FRAME_pushl()
- shll %ecx C size in byte pairs
- pushl %edi FRAME_pushl()
- ifdef(`PIC',`
- pushl %ebx FRAME_pushl()
- pushl %ebp FRAME_pushl()
- call L(here) FRAME_pushl()
- L(here):
- movl PARAM_SRC1, %esi
- popl %ebp FRAME_popl()
- movl PARAM_SRC2, %edi
- addl $_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebp
- xorl %ebx, %ebx C byte
- xorl %edx, %edx C byte
- movl TABLE_NAME@GOT(%ebp), %ebp
- xorl %eax, %eax C total
- define(TABLE,`(%ebp,$1)')
- ',`
- dnl non-PIC
- movl PARAM_SRC1, %esi
- movl PARAM_SRC2, %edi
- xorl %eax, %eax C total
- pushl %ebx FRAME_pushl()
- xorl %edx, %edx C byte
- xorl %ebx, %ebx C byte
- define(TABLE,`TABLE_NAME($1)')
- ')
- C The nop after the xorb seems necessary. Although a movb might be
- C expected to go down the V pipe in the second cycle of the xorb, it
- C doesn't and costs an extra 2 cycles.
- L(top):
- C eax total
- C ebx byte
- C ecx counter, 2*size to 2
- C edx byte
- C esi src1
- C edi src2
- C ebp [PIC] table
- addl %ebx, %eax
- movb -1(%esi,%ecx,2), %bl
- addl %edx, %eax
- movb -1(%edi,%ecx,2), %dl
- xorb %dl, %bl
- movb -2(%esi,%ecx,2), %dl
- xorb -2(%edi,%ecx,2), %dl
- nop
- movb TABLE(%ebx), %bl
- decl %ecx
- movb TABLE(%edx), %dl
- jnz L(top)
- ifdef(`PIC',`
- popl %ebp
- ')
- addl %ebx, %eax
- popl %ebx
- addl %edx, %eax
- popl %edi
- popl %esi
- ret
- EPILOGUE()