submul_1.asm

a very popular packet of cryptography tools,it encloses the most common used algorithm and protocols

dnl  S/390 mpn_submul_1 -- Multiply a limb vector with a limb and subtract the
dnl  result from a second limb vector.

dnl  Copyright 2001 Free Software Foundation, Inc.

dnl  This file is part of the GNU MP Library.

dnl  The GNU MP Library is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU Lesser General Public License as published
dnl  by the Free Software Foundation; either version 2.1 of the License, or (at
dnl  your option) any later version.

dnl  The GNU MP Library is distributed in the hope that it will be useful, but
dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
dnl  License for more details.

dnl  You should have received a copy of the GNU Lesser General Public License
dnl  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
dnl  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
dnl  MA 02111-1307, USA.

include(`../config.m4')

define(`rp',2)
define(`up',3)
define(`n',4)
define(`vlimb',5)
define(`cylimb',7)

ASM_START()
PROLOGUE(mpn_submul_1)
	stm	6,7,24(15)
	slr	cylimb,cylimb	# clear cylimb
	ltr	vlimb,vlimb
	jnl	.Loopp

.Loopn:	l	1,0(up)		# load from u
	lr	6,1		#
	mr	0,vlimb		# multiply signed
	alr	0,6		# add vlimb to phi
	sra	6,31		# make mask
	nr	6,vlimb		# 0 or vlimb
	alr	0,6		# conditionally add vlimb to phi
	alr	1,cylimb	# add carry limb to plo
	brc	8+4,+8		# branch if not carry
	ahi	0,1		# increment phi
	l	6,0(rp)		# load r limb
	slr	6,1		# add u limb to plo
	brc	2+1,+8		# branch if not carry
	ahi	0,1		# increment phi
	lr	cylimb,0	# new cylimb
	st	6,0(rp)		# store
	la	up,4(,up)
	la	rp,4(,rp)
	brct	n,.Loopn

	lr	2,cylimb
	lm	6,7,24(15)
	br	14

.Loopp:	l	1,0(up)		# load from u
	lr	6,1		#
	mr	0,vlimb		# multiply signed
	sra	6,31		# make mask
	nr	6,vlimb		# 0 or vlimb
	alr	0,6		# conditionally add vlimb to phi
	alr	1,cylimb	# add carry limb to plo
	brc	8+4,+8		# branch if not carry
	ahi	0,1		# increment phi
	l	6,0(rp)		# load r limb
	slr	6,1		# add u limb to plo
	brc	2+1,+8		# branch if not carry
	ahi	0,1		# increment phi
	lr	cylimb,0	# new cylimb
	st	6,0(rp)		# store
	la	up,4(,up)
	la	rp,4(,rp)
	brct	n,.Loopp

	lr	2,cylimb
	lm	6,7,24(15)
	br	14
EPILOGUE(mpn_submul_1)