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mpih-lshift.S
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/* PowerPC-32 lshift
*
* Copyright (C) 1995, 1998, 2002 Free Software Foundation, Inc.
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "sysdep.h"
#include "asm-syntax.h"
#ifndef USE_PPC_PATCHES
/*******************
* mpi_limb_t
* _gcry_mpih_lshift( mpi_ptr_t wp, (r3)
* mpi_ptr_t up, (r4)
* mpi_size_t usize, (r5)
* unsigned cnt) (r6)
*/
.toc
.csect .text[PR]
.align 2
.globl _gcry_mpih_lshift
.globl ._gcry_mpih_lshift
.csect _gcry_mpih_lshift[DS]
_gcry_mpih_lshift:
.long ._gcry_mpih_lshift, TOC[tc0], 0
.csect .text[PR]
._gcry_mpih_lshift:
mtctr 5 # copy size into CTR
slwi 0,5,2
add 7,3,0 # make r7 point at end of res
add 4,4,0 # make r4 point at end of s1
subfic 8,6,32
lwzu 11,-4(4) # load first s1 limb
srw 3,11,8 # compute function return value
bdz Lend1
Loop: lwzu 10,-4(4)
slw 9,11,6
srw 12,10,8
or 9,9,12
stwu 9,-4(7)
bdz Lend2
lwzu 11,-4(4)
slw 9,10,6
srw 12,11,8
or 9,9,12
stwu 9,-4(7)
bdnz Loop
Lend1: slw 0,11,6
stw 0,-4(7)
blr
Lend2: slw 0,10,6
stw 0,-4(7)
blr
#else
/* Shift a limb left, low level routine.
Copyright (C) 1996, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* mp_limb_t mpn_lshift (mp_ptr wp, mp_srcptr up, mp_size_t usize,
unsigned int cnt) */
EALIGN(_gcry_mpih_lshift,3,0)
mtctr %r5 # copy size into CTR
cmplwi %cr0,%r5,16 # is size < 16
slwi %r0,%r5,2
add %r7,%r3,%r0 # make r7 point at end of res
add %r4,%r4,%r0 # make r4 point at end of s1
lwzu %r11,-4(%r4) # load first s1 limb
subfic %r8,%r6,32
srw %r3,%r11,%r8 # compute function return value
bge %cr0,L(big) # branch if size >= 16
bdz L(end1)
0: lwzu %r10,-4(%r4)
slw %r9,%r11,%r6
srw %r12,%r10,%r8
or %r9,%r9,%r12
stwu %r9,-4(%r7)
bdz L(end2)
lwzu %r11,-4(%r4)
slw %r9,%r10,%r6
srw %r12,%r11,%r8
or %r9,%r9,%r12
stwu %r9,-4(%r7)
bdnz 0b
L(end1):slw %r0,%r11,%r6
stw %r0,-4(%r7)
blr
/* Guaranteed not to succeed. */
L(boom): tweq %r0,%r0
/* We imitate a case statement, by using (yuk!) fixed-length code chunks,
of size 4*12 bytes. We have to do this (or something) to make this PIC. */
L(big): mflr %r9
bltl- %cr0,L(boom) # Never taken, only used to set LR.
slwi %r10,%r6,4
mflr %r12
add %r10,%r12,%r10
slwi %r8,%r6,5
add %r10,%r8,%r10
mtctr %r10
addi %r5,%r5,-1
mtlr %r9
bctr
L(end2):slw %r0,%r10,%r6
stw %r0,-4(%r7)
blr
#define DO_LSHIFT(n) \
mtctr %r5; \
0: lwzu %r10,-4(%r4); \
slwi %r9,%r11,n; \
inslwi %r9,%r10,n,32-n; \
stwu %r9,-4(%r7); \
bdz- L(end2); \
lwzu %r11,-4(%r4); \
slwi %r9,%r10,n; \
inslwi %r9,%r11,n,32-n; \
stwu %r9,-4(%r7); \
bdnz 0b; \
b L(end1)
DO_LSHIFT(1)
DO_LSHIFT(2)
DO_LSHIFT(3)
DO_LSHIFT(4)
DO_LSHIFT(5)
DO_LSHIFT(6)
DO_LSHIFT(7)
DO_LSHIFT(8)
DO_LSHIFT(9)
DO_LSHIFT(10)
DO_LSHIFT(11)
DO_LSHIFT(12)
DO_LSHIFT(13)
DO_LSHIFT(14)
DO_LSHIFT(15)
DO_LSHIFT(16)
DO_LSHIFT(17)
DO_LSHIFT(18)
DO_LSHIFT(19)
DO_LSHIFT(20)
DO_LSHIFT(21)
DO_LSHIFT(22)
DO_LSHIFT(23)
DO_LSHIFT(24)
DO_LSHIFT(25)
DO_LSHIFT(26)
DO_LSHIFT(27)
DO_LSHIFT(28)
DO_LSHIFT(29)
DO_LSHIFT(30)
DO_LSHIFT(31)
END(_gcry_mpih_lshift)
#endif

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