78 lines
1.8 KiB
ArmAsm
78 lines
1.8 KiB
ArmAsm
/* ARM sub_n -- Subtract two limb vectors of the same length > 0 and store
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* sum in a third limb vector.
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*
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* Copyright (C) 2013 Jussi Kivilinna <jussi.kivilinna@iki.fi>
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*
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* This file is part of Libgcrypt.
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*
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* Libgcrypt is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* Libgcrypt is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, see <http://www.gnu.org/licenses/>.
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*
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* Note: This code is heavily based on the GNU MP Library (version 4.2.1).
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*/
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#include "sysdep.h"
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#include "asm-syntax.h"
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.syntax unified
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.arm
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/*******************
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* mpi_limb_t
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* _gcry_mpih_sub_n( mpi_ptr_t res_ptr, r0
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* mpi_ptr_t s1_ptr, r1
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* mpi_ptr_t s2_ptr, r2
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* mpi_size_t size) r3
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*/
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.text
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.globl _gcry_mpih_sub_n
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.type _gcry_mpih_sub_n,%function
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_gcry_mpih_sub_n:
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push {r4, r5, r6, r7, r8, r9, r10, lr};
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cmp r0, #0; /* prepare carry flag for sub */
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tst r3, #3;
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beq .Large_loop;
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.Loop:
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ldr r4, [r1], #4;
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sub r3, #1;
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ldr lr, [r2], #4;
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sbcs r4, lr;
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tst r3, #3;
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str r4, [r0], #4;
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bne .Loop;
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teq r3, #0;
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beq .Lend;
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.Large_loop:
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ldm r1!, {r4, r6, r8, r10};
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sub r3, #4;
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ldm r2!, {r5, r7, r9, lr};
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sbcs r4, r5;
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sbcs r6, r7;
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sbcs r8, r9;
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sbcs r10, lr;
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teq r3, #0;
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stm r0!, {r4, r6, r8, r10};
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bne .Large_loop;
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.Lend:
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sbc r0, r3, #0;
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neg r0, r0;
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pop {r4, r5, r6, r7, r8, r9, r10, pc};
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.size _gcry_mpih_sub_n,.-_gcry_mpih_sub_n;
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