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/* hppa1.1 submul_1 -- Multiply a limb vector with a limb and add
* the result to a second limb vector.
*
* Copyright (C) 1992, 1993, 1994, 1998,
* 2001, 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
*
* 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.
*/
/*******************
* mpi_limb_t
* _gcry_mpih_submul_1( mpi_ptr_t res_ptr, (r26)
* mpi_ptr_t s1_ptr, (r25)
* mpi_size_t s1_size, (r24)
* mpi_limb_t s2_limb) (r23)
*
*
* This runs at 12 cycles/limb on a PA7000. With the used instructions, it
* can not become faster due to data cache contention after a store. On the
* PA7100 it runs at 11 cycles/limb, and that can not be improved either,
* since only the xmpyu does not need the integer pipeline, so the only
* dual-issue we will get are addc+xmpyu. Unrolling could gain a cycle/limb
* on the PA7100.
*
* There are some ideas described in mul1.S that applies to this code too.
*
* It seems possible to make this run as fast as addmul_1, if we use
* sub,>>= %r29,%r19,%r22
* addi 1,%r28,%r28
* but that requires reworking the hairy software pipeline...
*/
.level 1.1
.code
.export _gcry_mpih_submul_1
.label _gcry_mpih_submul_1
.proc
.callinfo frame=64,no_calls
.entry
ldo 64(%r30),%r30
fldws,ma 4(%r25),%fr5
stw %r23,-16(%r30) ; move s2_limb ...
addib,= -1,%r24,L$just_one_limb
fldws -16(%r30),%fr4 ; ... into fr4
add %r0,%r0,%r0 ; clear carry
xmpyu %fr4,%fr5,%fr6
fldws,ma 4(%r25),%fr7
fstds %fr6,-16(%r30)
xmpyu %fr4,%fr7,%fr8
ldw -12(%r30),%r19 ; least significant limb in product
ldw -16(%r30),%r28
fstds %fr8,-16(%r30)
addib,= -1,%r24,L$end
ldw -12(%r30),%r1
; Main loop
.label L$loop
ldws 0(%r26),%r29
fldws,ma 4(%r25),%fr5
sub %r29,%r19,%r22
add %r22,%r19,%r0
stws,ma %r22,4(%r26)
addc %r28,%r1,%r19
xmpyu %fr4,%fr5,%fr6
ldw -16(%r30),%r28
fstds %fr6,-16(%r30)
addc %r0,%r28,%r28
addib,<> -1,%r24,L$loop
ldw -12(%r30),%r1
.label L$end
ldw 0(%r26),%r29
sub %r29,%r19,%r22
add %r22,%r19,%r0
stws,ma %r22,4(%r26)
addc %r28,%r1,%r19
ldw -16(%r30),%r28
ldws 0(%r26),%r29
addc %r0,%r28,%r28
sub %r29,%r19,%r22
add %r22,%r19,%r0
stws,ma %r22,4(%r26)
addc %r0,%r28,%r28
bv 0(%r2)
ldo -64(%r30),%r30
.label L$just_one_limb
xmpyu %fr4,%fr5,%fr6
ldw 0(%r26),%r29
fstds %fr6,-16(%r30)
ldw -12(%r30),%r1
ldw -16(%r30),%r28
sub %r29,%r1,%r22
add %r22,%r1,%r0
stw %r22,0(%r26)
addc %r0,%r28,%r28
bv 0(%r2)
ldo -64(%r30),%r30
.exit
.procend
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