source/libs/gmp/gmp-src/mpn/x86/pentium4/copyi.asm

   1 dnl  Pentium-4 mpn_copyi -- copy limb vector, incrementing.
   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 rep/movsl is very slow for small blocks on pentium4.  Its startup
  33 dnl  time seems to be about 110 cycles.  It then copies at a rate of one
  34 dnl  limb per cycle.  We therefore fall back to an open-coded 2 c/l copying
  35 dnl  loop for smaller sizes.
  36
  37 dnl  Ultimately, we may want to use 64-bit movd or 128-bit movdqu in some
  38 dnl  nifty unrolled arrangement.  Clearly, that could reach much higher
  39 dnl  speeds, at least for large blocks.
  40
  41 include(`../config.m4')
  42
  43
  44 defframe(PARAM_SIZE, 12)
  45 defframe(PARAM_SRC, 8)
  46 defframe(PARAM_DST,  4)
  47
  48         TEXT
  49         ALIGN(8)
  50
  51 PROLOGUE(mpn_copyi)
  52 deflit(`FRAME',0)
  53
  54         movl    PARAM_SIZE, %ecx
  55         cmpl    $150, %ecx
  56         jg      L(replmovs)
  57
  58         movl    PARAM_SRC, %eax
  59         movl    PARAM_DST, %edx
  60         movl    %ebx, PARAM_SIZE
  61         testl   %ecx, %ecx
  62         jz      L(end)
  63
  64 L(loop):
  65         movl    (%eax), %ebx
  66         leal    4(%eax), %eax
  67         addl    $-1, %ecx
  68         movl    %ebx, (%edx)
  69         leal    4(%edx), %edx
  70
  71         jnz     L(loop)
  72
  73 L(end):
  74         movl    PARAM_SIZE, %ebx
  75         ret
  76
  77 L(replmovs):
  78         cld     C better safe than sorry, see mpn/x86/README
  79
  80         movl    %esi, %eax
  81         movl    PARAM_SRC, %esi
  82         movl    %edi, %edx
  83         movl    PARAM_DST, %edi
  84
  85         rep
  86         movsl
  87
  88         movl    %eax, %esi
  89         movl    %edx, %edi
  90
  91         ret
  92
  93 EPILOGUE()