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()
