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Annotation of OpenXM_contrib/gmp/mpn/thumb/sub_n.s, Revision 1.1.1.1

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}