1dnl ARM/Thumb mpn_sub_n. 2 3dnl Copyright 1997, 2000, 2012 Free Software Foundation, Inc. 4 5dnl This file is part of the GNU MP Library. 6 7dnl The GNU MP Library is free software; you can redistribute it and/or modify 8dnl it under the terms of the GNU Lesser General Public License as published by 9dnl the Free Software Foundation; either version 3 of the License, or (at your 10dnl option) any later version. 11 12dnl The GNU MP Library is distributed in the hope that it will be useful, but 13dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 14dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 15dnl License for more details. 16 17dnl You should have received a copy of the GNU Lesser General Public License 18dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. 19 20include(`../config.m4') 21 22C INPUT PARAMETERS 23define(`rp', r0) 24define(`up', r1) 25define(`vp', r2) 26define(`n', r3) 27 28ASM_START() 29 .thumb 30PROLOGUE(mpn_sub_nc) 31 push {r4, r5, r6} 32 ldr r6, [sp, #12] C init carry save register 33 neg r6, r6 34 b L(top) 35EPILOGUE() 36PROLOGUE(mpn_sub_n) 37 push {r4, r5, r6} 38 mov r6, n C init carry save register 39 40L(top): ldmia up!, {r4} C load next limb from S1 41 cmp n, r6 C tricky carry restore 42 ldmia vp!, {r5} C load next limb from S2 43 sbc r4, r5 44 stmia rp!, {r4} C store result limb to RES 45 sbc r6, r6 C save negated carry 46 sub n, #1 47 bne L(top) 48 49 neg r0, r6 50 pop {r4, r5, r6} 51 bx lr 52EPILOGUE() 53