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Annotation of OpenXM_contrib/gmp/mpn/x86/k6/diveby3.asm, Revision 1.1

1.1     ! maekawa     1: dnl  AMD K6 mpn_divexact_by3 -- mpn division by 3, expecting no remainder.
        !             2: dnl
        !             3: dnl  K6: 11.0 cycles/limb
        !             4:
        !             5:
        !             6: dnl  Copyright (C) 2000 Free Software Foundation, Inc.
        !             7: dnl
        !             8: dnl  This file is part of the GNU MP Library.
        !             9: dnl
        !            10: dnl  The GNU MP Library is free software; you can redistribute it and/or
        !            11: dnl  modify it under the terms of the GNU Lesser General Public License as
        !            12: dnl  published by the Free Software Foundation; either version 2.1 of the
        !            13: dnl  License, or (at your option) any later version.
        !            14: dnl
        !            15: dnl  The GNU MP Library is distributed in the hope that it will be useful,
        !            16: dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            17: dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            18: dnl  Lesser General Public License for more details.
        !            19: dnl
        !            20: dnl  You should have received a copy of the GNU Lesser General Public
        !            21: dnl  License along with the GNU MP Library; see the file COPYING.LIB.  If
        !            22: dnl  not, write to the Free Software Foundation, Inc., 59 Temple Place -
        !            23: dnl  Suite 330, Boston, MA 02111-1307, USA.
        !            24:
        !            25:
        !            26: include(`../config.m4')
        !            27:
        !            28:
        !            29: C mp_limb_t mpn_divexact_by3c (mp_ptr dst, mp_srcptr src, mp_size_t size,
        !            30: C                              mp_limb_t carry);
        !            31: C
        !            32: C Using %esi in (%esi,%ecx,4) or 0(%esi,%ecx,4) addressing modes doesn't
        !            33: C lead to vector decoding, unlike plain (%esi) does.
        !            34:
        !            35: defframe(PARAM_CARRY,16)
        !            36: defframe(PARAM_SIZE, 12)
        !            37: defframe(PARAM_SRC,   8)
        !            38: defframe(PARAM_DST,   4)
        !            39:
        !            40: dnl  multiplicative inverse of 3, modulo 2^32
        !            41: deflit(INVERSE_3, 0xAAAAAAAB)
        !            42:
        !            43:        .text
        !            44:        ALIGN(32)
        !            45:
        !            46: PROLOGUE(mpn_divexact_by3c)
        !            47: deflit(`FRAME',0)
        !            48:
        !            49:        movl    PARAM_SIZE, %ecx
        !            50:        pushl   %esi            defframe_pushl(SAVE_ESI)
        !            51:
        !            52:        movl    PARAM_SRC, %esi
        !            53:        pushl   %edi            defframe_pushl(SAVE_EDI)
        !            54:
        !            55:        movl    PARAM_DST, %edi
        !            56:        pushl   %ebx            defframe_pushl(SAVE_EBX)
        !            57:
        !            58:        movl    PARAM_CARRY, %ebx
        !            59:        leal    (%esi,%ecx,4), %esi
        !            60:
        !            61:        pushl   $3              defframe_pushl(VAR_THREE)
        !            62:        leal    (%edi,%ecx,4), %edi
        !            63:
        !            64:        negl    %ecx
        !            65:
        !            66:
        !            67:        C Need 32 alignment for claimed speed, to avoid the movl store
        !            68:        C opcode/modrm crossing a cache line boundary
        !            69:
        !            70:        ALIGN(32)
        !            71: L(top):
        !            72:        C eax   scratch, low product
        !            73:        C ebx   carry limb (0 to 3)
        !            74:        C ecx   counter, limbs, negative
        !            75:        C edx   scratch, high product
        !            76:        C esi   &src[size]
        !            77:        C edi   &dst[size]
        !            78:        C ebp
        !            79:        C
        !            80:        C The 0(%esi,%ecx,4) form pads so the finishup "movl %ebx, %eax"
        !            81:        C doesn't cross a 32 byte boundary, saving a couple of cycles
        !            82:        C (that's a fixed couple, not per loop).
        !            83:
        !            84: Zdisp( movl,   0,(%esi,%ecx,4), %eax)
        !            85:        subl    %ebx, %eax
        !            86:
        !            87:        setc    %bl
        !            88:
        !            89:        imull   $INVERSE_3, %eax
        !            90:
        !            91:        movl    %eax, (%edi,%ecx,4)
        !            92:        addl    $2, %ecx
        !            93:
        !            94:        mull    VAR_THREE
        !            95:
        !            96:        addl    %edx, %ebx
        !            97:        loop    L(top)
        !            98:
        !            99:
        !           100:        movl    SAVE_ESI, %esi
        !           101:        movl    %ebx, %eax
        !           102:
        !           103:        movl    SAVE_EBX, %ebx
        !           104:
        !           105:        movl    SAVE_EDI, %edi
        !           106:        addl    $FRAME, %esp
        !           107:
        !           108:        ret
        !           109:
        !           110: EPILOGUE()