copyi.asm
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上传日期:2022-08-06
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- dnl Pentium-4 mpn_copyi -- copy limb vector, incrementing.
- dnl
- dnl Copyright 1999, 2000, 2001 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/.
- dnl The rep/movsl is very slow for small blocks on pentium4. Its startup
- dnl time seems to be about 110 cycles. It then copies at a rate of one
- dnl limb per cycle. We therefore fall back to an open-coded 2 c/l copying
- dnl loop for smaller sizes.
- dnl Ultimately, we may want to use 64-bit movd or 128-bit movdqu in some
- dnl nifty unrolled arrangement. Clearly, that could reach much higher
- dnl speeds, at least for large blocks.
- include(`../config.m4')
- defframe(PARAM_SIZE, 12)
- defframe(PARAM_SRC, 8)
- defframe(PARAM_DST, 4)
- TEXT
- ALIGN(8)
- PROLOGUE(mpn_copyi)
- deflit(`FRAME',0)
- movl PARAM_SIZE, %ecx
- cmpl $150, %ecx
- jg L(replmovs)
- movl PARAM_SRC, %eax
- movl PARAM_DST, %edx
- movl %ebx, PARAM_SIZE
- testl %ecx, %ecx
- jz L(end)
- L(loop):
- movl (%eax), %ebx
- leal 4(%eax), %eax
- addl $-1, %ecx
- movl %ebx, (%edx)
- leal 4(%edx), %edx
- jnz L(loop)
- L(end):
- movl PARAM_SIZE, %ebx
- ret
- L(replmovs):
- cld C better safe than sorry, see mpn/x86/README
- movl %esi, %eax
- movl PARAM_SRC, %esi
- movl %edi, %edx
- movl PARAM_DST, %edi
- rep
- movsl
- movl %eax, %esi
- movl %edx, %edi
- ret
- EPILOGUE()