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Annotation of OpenXM_contrib/gmp/mpn/x86/k7/mmx/com_n.asm, Revision 1.1

1.1     ! ohara       1: dnl  AMD Athlon mpn_com_n -- mpn bitwise one's complement.
        !             2:
        !             3: dnl  Copyright 2002 Free Software Foundation, Inc.
        !             4: dnl
        !             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
        !             8: dnl  modify it under the terms of the GNU Lesser General Public License as
        !             9: dnl  published by the Free Software Foundation; either version 2.1 of the
        !            10: dnl  License, or (at your option) any later version.
        !            11: dnl
        !            12: dnl  The GNU MP Library is distributed in the hope that it will be useful,
        !            13: dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            14: dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            15: dnl  Lesser General Public License for more details.
        !            16: dnl
        !            17: dnl  You should have received a copy of the GNU Lesser General Public
        !            18: dnl  License along with the GNU MP Library; see the file COPYING.LIB.  If
        !            19: dnl  not, write to the Free Software Foundation, Inc., 59 Temple Place -
        !            20: dnl  Suite 330, Boston, MA 02111-1307, USA.
        !            21:
        !            22: include(`../config.m4')
        !            23:
        !            24:
        !            25: C K7: 1.0 cycles/limb
        !            26:
        !            27:
        !            28: C void mpn_com_n (mp_ptr dst, mp_srcptr src, mp_size_t size);
        !            29: C
        !            30: C The loop form below is necessary for the claimed speed.  It needs to be
        !            31: C aligned to a 16 byte boundary and only 16 bytes long.  Maybe that's so it
        !            32: C fits in a BTB entry.  The adjustments to %eax and %edx avoid offsets on
        !            33: C the movq's and achieve the necessary size.
        !            34: C
        !            35: C If both src and dst are 4mod8, the loop runs at 1.5 c/l.  So long as one
        !            36: C of the two is 0mod8, it runs at 1.0 c/l.  On that basis dst is checked
        !            37: C (offset by the size, as per the loop addressing) and one high limb
        !            38: C processed separately to get alignment.
        !            39: C
        !            40: C The padding for the nails case is unattractive, but shouldn't cost any
        !            41: C cycles.  Explicit .byte's guarantee the desired instructions, at a point
        !            42: C where we're probably stalled waiting for loads anyway.
        !            43: C
        !            44: C Enhancements:
        !            45: C
        !            46: C The combination load/pxor/store might be able to be unrolled to approach
        !            47: C 0.5 c/l if desired.
        !            48:
        !            49: defframe(PARAM_SIZE,12)
        !            50: defframe(PARAM_SRC, 8)
        !            51: defframe(PARAM_DST, 4)
        !            52:
        !            53:        TEXT
        !            54:        ALIGN(16)
        !            55:
        !            56: PROLOGUE(mpn_com_n)
        !            57: deflit(`FRAME',0)
        !            58:
        !            59:        movl    PARAM_DST, %edx
        !            60:        movl    PARAM_SIZE, %ecx
        !            61:        pcmpeqd %mm7, %mm7
        !            62:
        !            63:        leal    (%edx,%ecx,4), %eax
        !            64:        andl    $4, %eax
        !            65: ifelse(GMP_NAIL_BITS,0,,
        !            66: `      psrld   $GMP_NAIL_BITS, %mm7')          C GMP_NUMB_MASK
        !            67:
        !            68:        movl    PARAM_SRC, %eax
        !            69:        movd    -4(%eax,%ecx,4), %mm0           C src high limb
        !            70:
        !            71: ifelse(GMP_NAIL_BITS,0,,
        !            72: `      C padding for alignment below
        !            73:        .byte   0x8d, 0xb6, 0x00, 0x00, 0x00, 0x00      C lea 0(%esi),%esi
        !            74:        .byte   0x8d, 0xbf, 0x00, 0x00, 0x00, 0x00      C lea 0(%edi),%edi
        !            75: ')
        !            76:
        !            77:        jz      L(aligned)
        !            78:
        !            79:        pxor    %mm7, %mm0
        !            80:        movd    %mm0, -4(%edx,%ecx,4)           C dst high limb
        !            81:        decl    %ecx
        !            82:        jz      L(done)
        !            83: L(aligned):
        !            84:
        !            85:        addl    $4, %eax
        !            86:        addl    $4, %edx
        !            87:        decl    %ecx
        !            88:        jz      L(one)
        !            89:
        !            90:        C offset 0x30 for no nails, or 0x40 for nails
        !            91:        ALIGN(16)
        !            92: L(top):
        !            93:        C eax   src
        !            94:        C ebx
        !            95:        C ecx   counter
        !            96:        C edx   dst
        !            97:
        !            98:        subl    $2, %ecx
        !            99:        movq    (%eax,%ecx,4), %mm0
        !           100:        pxor    %mm7, %mm0
        !           101:        movq    %mm0, (%edx,%ecx,4)
        !           102:        jg      L(top)
        !           103:
        !           104:        jnz     L(done)                         C if size even
        !           105:
        !           106: L(one):
        !           107:        movd    -4(%eax), %mm0                  C src low limb
        !           108:        pxor    %mm7, %mm0
        !           109:        movd    %mm0, -4(%edx)                  C dst low limb
        !           110:
        !           111: L(done):
        !           112:        emms
        !           113:
        !           114:        ret
        !           115:
        !           116: EPILOGUE()