/* PowerPC-32 rshift
*
* 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_rshift( 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_rshift
.globl ._gcry_mpih_rshift
.csect _gcry_mpih_rshift[DS]
_gcry_mpih_rshift:
.long ._gcry_mpih_rshift, TOC[tc0], 0
.csect .text[PR]
._gcry_mpih_rshift:
mtctr 5 # copy size into CTR
addi 7,3,-4 # move adjusted res_ptr to free return reg
subfic 8,6,32
lwz 11,0(4) # load first s1 limb
slw 3,11,8 # compute function return value
bdz Lend1
Loop: lwzu 10,4(4)
srw 9,11,6
slw 12,10,8
or 9,9,12
stwu 9,4(7)
bdz Lend2
lwzu 11,4(4)
srw 9,10,6
slw 12,11,8
or 9,9,12
stwu 9,4(7)
bdnz Loop
Lend1: srw 0,11,6
stw 0,4(7)
blr
Lend2: srw 0,10,6
stw 0,4(7)
blr
#else
/* Shift a limb right, low level routine.
Copyright (C) 1995, 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. */
/* INPUT PARAMETERS
res_ptr r3
s1_ptr r4
size r5
cnt r6 */
ENTRY(_gcry_mpih_rshift)
mtctr 5 # copy size into CTR
addi 7,3,-4 # move adjusted res_ptr to free return reg
subfic 8,6,32
lwz 11,0(4) # load first s1 limb
slw 3,11,8 # compute function return value
bdz 1f
0: lwzu 10,4(4)
srw 9,11,6
slw 12,10,8
or 9,9,12
stwu 9,4(7)
bdz 2f
lwzu 11,4(4)
srw 9,10,6
slw 12,11,8
or 9,9,12
stwu 9,4(7)
bdnz 0b
1: srw 0,11,6
stw 0,4(7)
blr
2: srw 0,10,6
stw 0,4(7)
blr
END(_gcry_mpih_rshift)
#endif
