copyi.asm
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上传日期:2022-08-06
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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()