65 lines
1.9 KiB
ArmAsm
65 lines
1.9 KiB
ArmAsm
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/* IBM POWER rshift
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*
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* Copyright (C) 1992, 1994, 1999, 2002 Free Software Foundation, Inc.
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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, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include "sysdep.h"
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#include "asm-syntax.h"
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/*
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# INPUT PARAMETERS
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# res_ptr r3
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# s_ptr r4
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# size r5
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# cnt r6
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*/
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.toc
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.extern _gcry_mpih_rshift[DS]
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.extern ._gcry_mpih_rshift
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.csect [PR]
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.align 2
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.globl _gcry_mpih_rshift
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.globl ._gcry_mpih_rshift
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.csect _gcry_mpih_rshift[DS]
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_gcry_mpih_rshift:
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.long ._gcry_mpih_rshift, TOC[tc0], 0
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.csect [PR]
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._gcry_mpih_rshift:
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sfi 8,6,32
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mtctr 5 # put limb count in CTR loop register
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l 0,0(4) # read least significant limb
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ai 9,3,-4 # adjust res_ptr since it's offset in the stu:s
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sle 3,0,8 # compute carry limb, and init MQ register
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bdz Lend2 # if just one limb, skip loop
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lu 0,4(4) # read 2:nd least significant limb
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sleq 7,0,8 # compute least significant limb of result
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bdz Lend # if just two limb, skip loop
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Loop: lu 0,4(4) # load next higher limb
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stu 7,4(9) # store previous result during read latency
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sleq 7,0,8 # compute result limb
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bdn Loop # loop back until CTR is zero
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Lend: stu 7,4(9) # store 2:nd most significant limb
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Lend2: sre 7,0,6 # compute most significant limb
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st 7,4(9) # store it
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br
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