dnl Pentium-4 mpn_copyi -- copy limb vector, incrementing. dnl Copyright 1999-2001 Free Software Foundation, Inc. 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 modify dnl it under the terms of either: dnl dnl * the GNU Lesser General Public License as published by the Free dnl Software Foundation; either version 3 of the License, or (at your dnl option) any later version. dnl dnl or dnl dnl * the GNU General Public License as published by the Free Software dnl Foundation; either version 2 of the License, or (at your option) any dnl later version. dnl dnl or both in parallel, as here. dnl dnl The GNU MP Library is distributed in the hope that it will be useful, but dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License dnl for more details. dnl dnl You should have received copies of the GNU General Public License and the dnl GNU Lesser General Public License along with the GNU MP Library. If not, dnl see https://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() |