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dnl x86 mpn_copyi -- copy limb vector, incrementing.
dnl Copyright (C) 1999, 2000 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 2.1 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
dnl License along with the GNU MP Library; see the file COPYING.LIB. If
dnl not, write to the Free Software Foundation, Inc., 59 Temple Place -
dnl Suite 330, Boston, MA 02111-1307, USA.
include(`../config.m4')
C void mpn_copyi (mp_ptr dst, mp_srcptr src, mp_size_t size);
C
C Copy src,size to dst,size, working from low to high addresses.
C
C The code here is very generic and can be expected to be reasonable on all
C the x86 family.
C
C P5 - 1.0 cycles/limb.
C
C P6 - 0.75 cycles/limb. An MMX based copy was tried, but was found to be
C slower than a rep movs in all cases. The fastest MMX found was 0.8
C cycles/limb (when fully aligned). A rep movs seems to have a startup
C time of about 15 cycles, but doing something special for small sizes
C could lead to a branch misprediction that would destroy any saving.
C For now a plain rep movs seems ok for P6.
defframe(PARAM_SIZE,12)
defframe(PARAM_SRC, 8)
defframe(PARAM_DST, 4)
deflit(`FRAME',0)
.text
ALIGN(32)
C eax saved esi
C ebx
C ecx counter
C edx saved edi
C esi src
C edi dst
C ebp
PROLOGUE(mpn_copyi)
movl PARAM_SIZE, %ecx
movl %esi, %eax
movl PARAM_SRC, %esi
movl %edi, %edx
movl PARAM_DST, %edi
cld C better safe than sorry, see mpn/x86/README.family
rep
movsl
movl %eax, %esi
movl %edx, %edi
ret
EPILOGUE()
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