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Annotation of OpenXM_contrib/gmp/mpn/thumb/sub_n.s, Revision 1.1

1.1     ! maekawa     1: @ ARM/Thumb __gmpn_sub -- Subtract two limb vectors of the same length > 0 and
        !             2: @ store difference in a third limb vector.
        !             3:
        !             4: @ Copyright (C) 1997, 2000 Free Software Foundation, Inc.
        !             5:
        !             6: @ This file is part of the GNU MP Library.
        !             7:
        !             8: @ The GNU MP Library is free software; you can redistribute it and/or modify
        !             9: @ it under the terms of the GNU Lesser General Public License as published by
        !            10: @ the Free Software Foundation; either version 2.1 of the License, or (at your
        !            11: @ option) any later version.
        !            12:
        !            13: @ The GNU MP Library is distributed in the hope that it will be useful, but
        !            14: @ WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            15: @ or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
        !            16: @ License for more details.
        !            17:
        !            18: @ You should have received a copy of the GNU Lesser General Public License
        !            19: @ along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
        !            20: @ the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            21: @ MA 02111-1307, USA.
        !            22:
        !            23:
        !            24: @ INPUT PARAMETERS
        !            25: @ RES_ptr      r0
        !            26: @ S1_ptr       r1
        !            27: @ S2_ptr       r2
        !            28: @ SIZE         r3
        !            29:
        !            30: @ NOT TESTED CODE
        !            31:
        !            32:        .text
        !            33:        .thumb
        !            34:        .align  0
        !            35:        .global ___gmpn_sub_n
        !            36: ___gmpn_sub_n:
        !            37:        push    {r4, r5, r6, lr}
        !            38:        mov     r6, #1                  @ init carry save register
        !            39:
        !            40: Loop:  sub     r6, #1                  @ restore carry (set iff r6 was 0)
        !            41:        ldmia   r1!, {r4}               @ load next limb from S1
        !            42:        ldmia   r2!, {r5}               @ load next limb from S2
        !            43:        sbc     r4, r5
        !            44:        stmia   r0!, {r4}               @ store result limb to RES
        !            45:        sbc     r6, r6                  @ save negated carry
        !            46:        sub     r3, #1
        !            47:        bge     Loop                    @ loop back while remaining count >= 4
        !            48:
        !            49:        mov     r0, r6
        !            50:        pop     {r4, r5, r6, pc}