2002-06-29 16:15:02 +02:00
|
|
|
/* alpha rshift
|
|
|
|
|
* Copyright (C) 1994, 1995, 1998, 1999,
|
|
|
|
|
* 2000, 2001 Free Software Foundation, Inc.
|
|
|
|
|
*
|
|
|
|
|
* This file is part of GNUPG.
|
|
|
|
|
*
|
|
|
|
|
* GNUPG is free software; you can redistribute it and/or modify
|
|
|
|
|
* it under the terms of the GNU General Public License as published by
|
|
|
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
|
|
|
* (at your option) any later version.
|
|
|
|
|
*
|
|
|
|
|
* GNUPG 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 General Public License for more details.
|
|
|
|
|
*
|
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
|
|
|
* along with this program; if not, write to the Free Software
|
2005-05-31 10:39:18 +02:00
|
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
|
|
|
|
|
* USA.
|
2002-06-29 16:15:02 +02:00
|
|
|
*
|
|
|
|
|
* Note: This code is heavily based on the GNU MP Library.
|
|
|
|
|
* Actually it's the same code with only minor changes in the
|
|
|
|
|
* way the data is stored; this is to support the abstraction
|
|
|
|
|
* of an optional secure memory allocation which may be used
|
|
|
|
|
* to avoid revealing of sensitive data due to paging etc.
|
|
|
|
|
* The GNU MP Library itself is published under the LGPL;
|
|
|
|
|
* however I decided to publish this code under the plain GPL.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/*******************
|
|
|
|
|
* mpi_limb_t
|
|
|
|
|
* mpihelp_rshift( mpi_ptr_t wp, (r16)
|
|
|
|
|
* mpi_ptr_t up, (r17)
|
|
|
|
|
* mpi_size_t usize, (r18)
|
|
|
|
|
* unsigned cnt) (r19)
|
|
|
|
|
*
|
|
|
|
|
* This code runs at 4.8 cycles/limb on the 21064. With infinite unrolling,
|
|
|
|
|
* it would take 4 cycles/limb. It should be possible to get down to 3
|
|
|
|
|
* cycles/limb since both ldq and stq can be paired with the other used
|
|
|
|
|
* instructions. But there are many restrictions in the 21064 pipeline that
|
|
|
|
|
* makes it hard, if not impossible, to get down to 3 cycles/limb:
|
|
|
|
|
*
|
|
|
|
|
* 1. ldq has a 3 cycle delay, srl and sll have a 2 cycle delay.
|
|
|
|
|
* 2. Only aligned instruction pairs can be paired.
|
|
|
|
|
* 3. The store buffer or silo might not be able to deal with the bandwidth.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
.set noreorder
|
|
|
|
|
.set noat
|
|
|
|
|
.text
|
|
|
|
|
.align 3
|
|
|
|
|
.globl mpihelp_rshift
|
|
|
|
|
.ent mpihelp_rshift
|
|
|
|
|
mpihelp_rshift:
|
|
|
|
|
.frame $30,0,$26,0
|
|
|
|
|
|
|
|
|
|
ldq $4,0($17) # load first limb
|
|
|
|
|
addq $17,8,$17
|
|
|
|
|
subq $31,$19,$7
|
|
|
|
|
subq $18,1,$18
|
|
|
|
|
and $18,4-1,$20 # number of limbs in first loop
|
|
|
|
|
sll $4,$7,$0 # compute function result
|
|
|
|
|
|
|
|
|
|
beq $20,.R0
|
|
|
|
|
subq $18,$20,$18
|
|
|
|
|
|
|
|
|
|
.align 3
|
|
|
|
|
.Roop0:
|
|
|
|
|
ldq $3,0($17)
|
|
|
|
|
addq $16,8,$16
|
|
|
|
|
addq $17,8,$17
|
|
|
|
|
subq $20,1,$20
|
|
|
|
|
srl $4,$19,$5
|
|
|
|
|
sll $3,$7,$6
|
|
|
|
|
bis $3,$3,$4
|
|
|
|
|
bis $5,$6,$8
|
|
|
|
|
stq $8,-8($16)
|
|
|
|
|
bne $20,.Roop0
|
|
|
|
|
|
|
|
|
|
.R0: beq $18,.Rend
|
|
|
|
|
|
|
|
|
|
.align 3
|
|
|
|
|
.Roop: ldq $3,0($17)
|
|
|
|
|
addq $16,32,$16
|
|
|
|
|
subq $18,4,$18
|
|
|
|
|
srl $4,$19,$5
|
|
|
|
|
sll $3,$7,$6
|
|
|
|
|
|
|
|
|
|
ldq $4,8($17)
|
|
|
|
|
srl $3,$19,$1
|
|
|
|
|
bis $5,$6,$8
|
|
|
|
|
stq $8,-32($16)
|
|
|
|
|
sll $4,$7,$2
|
|
|
|
|
|
|
|
|
|
ldq $3,16($17)
|
|
|
|
|
srl $4,$19,$5
|
|
|
|
|
bis $1,$2,$8
|
|
|
|
|
stq $8,-24($16)
|
|
|
|
|
sll $3,$7,$6
|
|
|
|
|
|
|
|
|
|
ldq $4,24($17)
|
|
|
|
|
srl $3,$19,$1
|
|
|
|
|
bis $5,$6,$8
|
|
|
|
|
stq $8,-16($16)
|
|
|
|
|
sll $4,$7,$2
|
|
|
|
|
|
|
|
|
|
addq $17,32,$17
|
|
|
|
|
bis $1,$2,$8
|
|
|
|
|
stq $8,-8($16)
|
|
|
|
|
|
|
|
|
|
bgt $18,.Roop
|
|
|
|
|
|
|
|
|
|
.Rend: srl $4,$19,$8
|
|
|
|
|
stq $8,0($16)
|
|
|
|
|
ret $31,($26),1
|
|
|
|
|
.end mpihelp_rshift
|
|
|
|
|
|
