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dnl AMD K7 mpn_copyi -- copy limb vector, incrementing.
dnl Copyright 1999, 2000, 2002, 2003 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/.
include(`../config.m4')
C alignment dst/src, A=0mod8 N=4mod8
C A/A A/N N/A N/N
C K7 0.75 1.0 1.0 0.75
C void mpn_copyi (mp_ptr dst, mp_srcptr src, mp_size_t size);
C
C Copy src,size to dst,size.
C
C This code at 0.75 or 1.0 c/l is always faster than a plain rep movsl at
C 1.33 c/l.
C
C The K7 can do a 64-bit load and 64-bit store in one cycle (optimization
C guile 22007 appendix B), so 0.5 c/l should be possible, however nothing
C under 0.7 c/l is known. Apparently only two 32-bit stores can be done in
C one cycle, so perhaps some scheduling is needed to ensure it's a
C load+store in each cycle, not store+store.
C
C If both source and destination are unaligned then one limb is processed at
C the start to make them aligned and so get 0.75 c/l, whereas if they'd been
C used unaligned it would be 1.5 c/l.
defframe(PARAM_SIZE,12)
defframe(PARAM_SRC, 8)
defframe(PARAM_DST, 4)
dnl parameter space reused
define(SAVE_EBX,`PARAM_SIZE')
dnl minimum 5 since the unrolled code can't handle less than 5
deflit(UNROLL_THRESHOLD, 5)
TEXT
ALIGN(32)
PROLOGUE(mpn_copyi)
deflit(`FRAME',0)
movl PARAM_SIZE, %ecx
movl %ebx, SAVE_EBX
movl PARAM_SRC, %eax
movl PARAM_DST, %edx
cmpl $UNROLL_THRESHOLD, %ecx
jae L(unroll)
orl %ecx, %ecx
jz L(simple_done)
L(simple):
C eax src, incrementing
C ebx scratch
C ecx counter
C edx dst, incrementing
C
C this loop is 2 cycles/limb
movl (%eax), %ebx
movl %ebx, (%edx)
decl %ecx
leal 4(%eax), %eax
leal 4(%edx), %edx
jnz L(simple)
L(simple_done):
movl SAVE_EBX, %ebx
ret
L(unroll):
movl %eax, %ebx
leal -12(%eax,%ecx,4), %eax C src end - 12
subl $3, %ecx C size-3
andl %edx, %ebx
leal (%edx,%ecx,4), %edx C dst end - 12
negl %ecx
testl $4, %ebx C testl to pad code closer to 16 bytes for L(top)
jz L(aligned)
C both src and dst unaligned, process one limb to align them
movl (%eax,%ecx,4), %ebx
movl %ebx, (%edx,%ecx,4)
incl %ecx
L(aligned):
ALIGN(16)
L(top):
C eax src end - 12
C ebx
C ecx counter, negative, limbs
C edx dst end - 12
movq (%eax,%ecx,4), %mm0
movq 8(%eax,%ecx,4), %mm1
addl $4, %ecx
movq %mm0, -16(%edx,%ecx,4)
movq %mm1, -16+8(%edx,%ecx,4)
ja L(top) C jump no carry and not zero
C now %ecx is 0 to 3 representing respectively 3 to 0 limbs remaining
testb $2, %cl
jnz L(finish_not_two)
movq (%eax,%ecx,4), %mm0
movq %mm0, (%edx,%ecx,4)
L(finish_not_two):
testb $1, %cl
jnz L(done)
movl 8(%eax), %ebx
movl %ebx, 8(%edx)
L(done):
movl SAVE_EBX, %ebx
emms
ret
EPILOGUE()
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