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Annotation of OpenXM_contrib/gmp/mpn/m68k/rshift.asm, Revision 1.1

1.1     ! ohara       1: dnl  mc68020 mpn_rshift -- mpn right shift.
        !             2: dnl
        !             3: dnl            cycles/limb
        !             4: dnl         shift==1  shift>1
        !             5: dnl  68040:    7.0      9.5
        !             6:
        !             7: dnl  Copyright 1996, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
        !             8: dnl
        !             9: dnl  This file is part of the GNU MP Library.
        !            10: dnl
        !            11: dnl  The GNU MP Library is free software; you can redistribute it and/or
        !            12: dnl  modify it under the terms of the GNU Lesser General Public License as
        !            13: dnl  published by the Free Software Foundation; either version 2.1 of the
        !            14: dnl  License, or (at your option) any later version.
        !            15: dnl
        !            16: dnl  The GNU MP Library is distributed in the hope that it will be useful,
        !            17: dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            18: dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            19: dnl  Lesser General Public License for more details.
        !            20: dnl
        !            21: dnl  You should have received a copy of the GNU Lesser General Public
        !            22: dnl  License along with the GNU MP Library; see the file COPYING.LIB.  If
        !            23: dnl  not, write to the Free Software Foundation, Inc., 59 Temple Place -
        !            24: dnl  Suite 330, Boston, MA 02111-1307, USA.
        !            25:
        !            26: include(`../config.m4')
        !            27:
        !            28:
        !            29: C INPUT PARAMETERS
        !            30: C res_ptr      (sp + 4)
        !            31: C s_ptr                (sp + 8)
        !            32: C s_size       (sp + 16)
        !            33: C cnt          (sp + 12)
        !            34:
        !            35: define(res_ptr, `a1')
        !            36: define(s_ptr,   `a0')
        !            37: define(s_size,  `d6')
        !            38: define(cnt,     `d4')
        !            39:
        !            40: PROLOGUE(mpn_rshift)
        !            41: C Save used registers on the stack.
        !            42:        moveml  d2-d6/a2, M(-,sp)
        !            43:
        !            44: C Copy the arguments to registers.
        !            45:        movel   M(sp,28), res_ptr
        !            46:        movel   M(sp,32), s_ptr
        !            47:        movel   M(sp,36), s_size
        !            48:        movel   M(sp,40), cnt
        !            49:
        !            50:        moveql  #1, d5
        !            51:        cmpl    d5, cnt
        !            52:        bne     L(Lnormal)
        !            53:        cmpl    res_ptr, s_ptr
        !            54:        bls     L(Lspecial)             C jump if res_ptr >= s_ptr
        !            55:
        !            56: ifelse(scale_available_p,1,`
        !            57:        lea     M(res_ptr,s_size,l,4), a2
        !            58: ',`
        !            59:        movel   s_size, d0
        !            60:        asll    #2, d0
        !            61:        lea     M(res_ptr,d0,l), a2
        !            62: ')
        !            63:        cmpl    s_ptr, a2
        !            64:        bls     L(Lspecial)             C jump if s_ptr >= res_ptr + s_size
        !            65:
        !            66: L(Lnormal:)
        !            67:        moveql  #32, d5
        !            68:        subl    cnt, d5
        !            69:        movel   M(s_ptr,+), d2
        !            70:        movel   d2, d0
        !            71:        lsll    d5, d0          C compute carry limb
        !            72:
        !            73:        lsrl    cnt, d2
        !            74:        movel   d2, d1
        !            75:        subql   #1, s_size
        !            76:        beq     L(Lend)
        !            77:        lsrl    #1, s_size
        !            78:        bcs     L(L1)
        !            79:        subql   #1, s_size
        !            80:
        !            81: L(Loop:)
        !            82:        movel   M(s_ptr,+), d2
        !            83:        movel   d2, d3
        !            84:        lsll    d5, d3
        !            85:        orl     d3, d1
        !            86:        movel   d1, M(res_ptr,+)
        !            87:        lsrl    cnt, d2
        !            88: L(L1:)
        !            89:        movel   M(s_ptr,+), d1
        !            90:        movel   d1, d3
        !            91:        lsll    d5, d3
        !            92:        orl     d3, d2
        !            93:        movel   d2, M(res_ptr,+)
        !            94:        lsrl    cnt, d1
        !            95:
        !            96:        dbf     s_size, L(Loop)
        !            97:        subl    #0x10000, s_size
        !            98:        bcc     L(Loop)
        !            99:
        !           100: L(Lend:)
        !           101:        movel   d1, M(res_ptr)  C store most significant limb
        !           102:
        !           103: C Restore used registers from stack frame.
        !           104:        moveml  M(sp,+), d2-d6/a2
        !           105:        rts
        !           106:
        !           107: C We loop from most significant end of the arrays, which is only permissable
        !           108: C if the source and destination don't overlap, since the function is
        !           109: C documented to work for overlapping source and destination.
        !           110:
        !           111: L(Lspecial:)
        !           112: ifelse(scale_available_p,1,`
        !           113:        lea     M(s_ptr,s_size,l,4), s_ptr
        !           114:        lea     M(res_ptr,s_size,l,4), res_ptr
        !           115: ',`
        !           116:        movel   s_size, d0
        !           117:        asll    #2, d0
        !           118:        addl    d0, s_ptr
        !           119:        addl    d0, res_ptr
        !           120: ')
        !           121:
        !           122:        clrl    d0                      C initialize carry
        !           123:        eorw    #1, s_size
        !           124:        lsrl    #1, s_size
        !           125:        bcc     L(LL1)
        !           126:        subql   #1, s_size
        !           127:
        !           128: L(LLoop:)
        !           129:        movel   M(-,s_ptr), d2
        !           130:        roxrl   #1, d2
        !           131:        movel   d2, M(-,res_ptr)
        !           132: L(LL1:)
        !           133:        movel   M(-,s_ptr), d2
        !           134:        roxrl   #1, d2
        !           135:        movel   d2, M(-,res_ptr)
        !           136:
        !           137:        dbf     s_size, L(LLoop)
        !           138:        roxrl   #1, d0          C save cy in msb
        !           139:        subl    #0x10000, s_size
        !           140:        bcs     L(LLend)
        !           141:        addl    d0, d0          C restore cy
        !           142:        bra     L(LLoop)
        !           143:
        !           144: L(LLend:)
        !           145: C Restore used registers from stack frame.
        !           146:        moveml  M(sp,+), d2-d6/a2
        !           147:        rts
        !           148:
        !           149: EPILOGUE(mpn_rshift)