copyd.asm
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上传日期:2022-08-06
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- dnl Pentium-4 mpn_copyd -- copy limb vector, decrementing.
- 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 std/rep/movsl/cld is very slow for small blocks on pentium4. Its
- dnl startup time seems to be about 165 cycles. It then needs 2.6 c/l.
- dnl We therefore use an open-coded 2 c/l copying loop.
- dnl Ultimately, we may want to use 64-bit movq 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_copyd)
- deflit(`FRAME',0)
- movl PARAM_SIZE, %ecx
- movl PARAM_SRC, %eax
- movl PARAM_DST, %edx
- movl %ebx, PARAM_SIZE
- addl $-1, %ecx
- js L(end)
- L(loop):
- movl (%eax,%ecx,4), %ebx
- movl %ebx, (%edx,%ecx,4)
- addl $-1, %ecx
- jns L(loop)
- L(end):
- movl PARAM_SIZE, %ebx
- ret
- EPILOGUE()