github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/x86/pentium4/copyd.asm (about)

     1  dnl  Pentium-4 mpn_copyd -- copy limb vector, decrementing.
     2  
     3  dnl  Copyright 1999-2001 Free Software Foundation, Inc.
     4  
     5  dnl  This file is part of the GNU MP Library.
     6  dnl
     7  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
     8  dnl  it under the terms of either:
     9  dnl
    10  dnl    * the GNU Lesser General Public License as published by the Free
    11  dnl      Software Foundation; either version 3 of the License, or (at your
    12  dnl      option) any later version.
    13  dnl
    14  dnl  or
    15  dnl
    16  dnl    * the GNU General Public License as published by the Free Software
    17  dnl      Foundation; either version 2 of the License, or (at your option) any
    18  dnl      later version.
    19  dnl
    20  dnl  or both in parallel, as here.
    21  dnl
    22  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
    23  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    24  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    25  dnl  for more details.
    26  dnl
    27  dnl  You should have received copies of the GNU General Public License and the
    28  dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
    29  dnl  see https://www.gnu.org/licenses/.
    30  
    31  
    32  dnl  The std/rep/movsl/cld is very slow for small blocks on pentium4.  Its
    33  dnl  startup time seems to be about 165 cycles.  It then needs 2.6 c/l.
    34  dnl  We therefore use an open-coded 2 c/l copying loop.
    35  
    36  dnl  Ultimately, we may want to use 64-bit movq or 128-bit movdqu in some
    37  dnl  nifty unrolled arrangement.  Clearly, that could reach much higher
    38  dnl  speeds, at least for large blocks.
    39  
    40  include(`../config.m4')
    41  
    42  
    43  defframe(PARAM_SIZE, 12)
    44  defframe(PARAM_SRC, 8)
    45  defframe(PARAM_DST,  4)
    46  
    47  	TEXT
    48  	ALIGN(8)
    49  
    50  PROLOGUE(mpn_copyd)
    51  deflit(`FRAME',0)
    52  
    53  	movl	PARAM_SIZE, %ecx
    54  
    55  	movl	PARAM_SRC, %eax
    56  	movl	PARAM_DST, %edx
    57  	movl	%ebx, PARAM_SIZE
    58  	addl	$-1, %ecx
    59  	js	L(end)
    60  
    61  L(loop):
    62  	movl	(%eax,%ecx,4), %ebx
    63  	movl	%ebx, (%edx,%ecx,4)
    64  	addl	$-1, %ecx
    65  
    66  	jns	L(loop)
    67  L(end):
    68  	movl	PARAM_SIZE, %ebx
    69  	ret
    70  
    71  EPILOGUE()