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Annotation of OpenXM_contrib/gmp/mpn/x86/pentium4/copyd.asm, Revision 1.1

1.1     ! ohara       1: dnl  Pentium-4 mpn_copyd -- copy limb vector, decrementing.
        !             2: dnl
        !             3:
        !             4: dnl  Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
        !             5: dnl
        !             6: dnl  This file is part of the GNU MP Library.
        !             7: dnl
        !             8: dnl  The GNU MP Library is free software; you can redistribute it and/or
        !             9: dnl  modify it under the terms of the GNU Lesser General Public License as
        !            10: dnl  published by the Free Software Foundation; either version 2.1 of the
        !            11: dnl  License, or (at your option) any later version.
        !            12: dnl
        !            13: dnl  The GNU MP Library is distributed in the hope that it will be useful,
        !            14: dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            15: dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            16: dnl  Lesser General Public License for more details.
        !            17: dnl
        !            18: dnl  You should have received a copy of the GNU Lesser General Public
        !            19: dnl  License along with the GNU MP Library; see the file COPYING.LIB.  If
        !            20: dnl  not, write to the Free Software Foundation, Inc., 59 Temple Place -
        !            21: dnl  Suite 330, Boston, MA 02111-1307, USA.
        !            22:
        !            23:
        !            24: dnl  The std/rep/movsl/cld is very slow for small blocks on pentium4.  Its
        !            25: dnl  startup time seems to be about 165 cycles.  It then copies at a rate of
        !            26: dnl  one limb per cycle.  We therefore fall back to an open-coded 2 c/l
        !            27: dnl  copying loop for smaller sizes.
        !            28:
        !            29: dnl  Ultimately, we may want to use 64-bit movq or 128-bit movdqu in some
        !            30: dnl  nifty unrolled arrangement.  Clearly, that could reach much higher
        !            31: dnl  speeds, at least for large blocks.
        !            32:
        !            33: include(`../config.m4')
        !            34:
        !            35:
        !            36: defframe(PARAM_SIZE, 12)
        !            37: defframe(PARAM_SRC, 8)
        !            38: defframe(PARAM_DST,  4)
        !            39:
        !            40:        TEXT
        !            41:        ALIGN(8)
        !            42:
        !            43: PROLOGUE(mpn_copyd)
        !            44: deflit(`FRAME',0)
        !            45:
        !            46:        movl    PARAM_SIZE, %ecx
        !            47:
        !            48:        movl    PARAM_SRC, %eax
        !            49:        movl    PARAM_DST, %edx
        !            50:        movl    %ebx, PARAM_SIZE
        !            51:        addl    $-1, %ecx
        !            52:        js      L(end)
        !            53:
        !            54: L(loop):
        !            55:        movl    (%eax,%ecx,4), %ebx
        !            56:        movl    %ebx, (%edx,%ecx,4)
        !            57:        addl    $-1, %ecx
        !            58:
        !            59:        jns     L(loop)
        !            60: L(end):
        !            61:        movl    PARAM_SIZE, %ebx
        !            62:        ret
        !            63:
        !            64: EPILOGUE()