dnl  x86 mpn_copyi -- copy limb vector, incrementing.

dnl  Copyright 1999-2002 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/.

include(`../config.m4')

C     cycles/limb  startup (approx)

C P5	  1.0	      35

C P6	  0.75	      45

C K6	  1.0	      30

C K7	  1.3	      65

C P4	  1.0	     120

C

C (Startup time includes some function call overheads.)

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 P6 -  An MMX based copy was tried, but was found to be slower than a rep

C       movs in all cases.  The fastest MMX found was 0.8 cycles/limb (when

C       fully aligned).  A rep movs seems to have a startup time of about 15

C       cycles, but doing something special for small sizes could lead to a

C       branch misprediction that would destroy any saving.  For now a plain

C       rep movs seems ok.

C

C K62 - We used to have a big chunk of code doing an MMX copy at 0.56 c/l if

C       aligned or a 1.0 rep movs if not.  But that seemed excessive since

C       it only got an advantage half the time, and even then only showed it

C       above 50 limbs or so.

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

	rep

	movsl

	movl	%eax, %esi

	movl	%edx, %edi

	ret

EPILOGUE()