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+ # Alpha __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
+ # store difference in a third limb vector.
+
+ # Copyright (C) 1995 Free Software Foundation, Inc.
+
+ # This file is part of the GNU MP Library.
+
+ # The GNU MP 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 MP 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 MP Library; see the file COPYING.LIB.  If not, write to
+ # the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+
+ # INPUT PARAMETERS
+ # res_ptr	$16
+ # s1_ptr	$17
+ # s2_ptr	$18
+ # size		$19
+
+	.set	noreorder
+	.set	noat
+.text
+	.align	3
+	.globl	__mpn_sub_n
+	.ent	__mpn_sub_n
+__mpn_sub_n:
+	.frame	$30,0,$26,0
+
+	or	$31,$31,$25		# clear cy
+	subq	$19,4,$19		# decr loop cnt
+	blt	$19,.Lend2		# if less than 4 limbs, goto 2nd loop
+ # Start software pipeline for 1st loop
+	ldq	$0,0($18)
+	ldq	$1,8($18)
+	ldq	$4,0($17)
+	ldq	$5,8($17)
+	addq	$17,32,$17		# update s1_ptr
+	ldq	$2,16($18)
+	subq	$4,$0,$20		# 1st main sub
+	ldq	$3,24($18)
+	subq	$19,4,$19		# decr loop cnt
+	ldq	$6,-16($17)
+	cmpult	$4,$20,$25		# compute cy from last sub
+	ldq	$7,-8($17)
+	addq	$1,$25,$28		# cy add
+	addq	$18,32,$18		# update s2_ptr
+	subq	$5,$28,$21		# 2nd main sub
+	cmpult	$28,$25,$8		# compute cy from last add
+	blt	$19,.Lend1		# if less than 4 limbs remain, jump
+ # 1st loop handles groups of 4 limbs in a software pipeline
+	.align	4
+.Loop:	cmpult	$5,$21,$25		# compute cy from last add
+	ldq	$0,0($18)
+	or	$8,$25,$25		# combine cy from the two adds
+	ldq	$1,8($18)
+	addq	$2,$25,$28		# cy add
+	ldq	$4,0($17)
+	subq	$6,$28,$22		# 3rd main sub
+	ldq	$5,8($17)
+	cmpult	$28,$25,$8		# compute cy from last add
+	cmpult	$6,$22,$25		# compute cy from last add
+	stq	$20,0($16)
+	or	$8,$25,$25		# combine cy from the two adds
+	stq	$21,8($16)
+	addq	$3,$25,$28		# cy add
+	subq	$7,$28,$23		# 4th main sub
+	cmpult	$28,$25,$8		# compute cy from last add
+	cmpult	$7,$23,$25		# compute cy from last add
+	addq	$17,32,$17		# update s1_ptr
+	or	$8,$25,$25		# combine cy from the two adds
+	addq	$16,32,$16		# update res_ptr
+	addq	$0,$25,$28		# cy add
+	ldq	$2,16($18)
+	subq	$4,$28,$20		# 1st main sub
+	ldq	$3,24($18)
+	cmpult	$28,$25,$8		# compute cy from last add
+	ldq	$6,-16($17)
+	cmpult	$4,$20,$25		# compute cy from last add
+	ldq	$7,-8($17)
+	or	$8,$25,$25		# combine cy from the two adds
+	subq	$19,4,$19		# decr loop cnt
+	stq	$22,-16($16)
+	addq	$1,$25,$28		# cy add
+	stq	$23,-8($16)
+	subq	$5,$28,$21		# 2nd main sub
+	addq	$18,32,$18		# update s2_ptr
+	cmpult	$28,$25,$8		# compute cy from last add
+	bge	$19,.Loop
+ # Finish software pipeline for 1st loop
+.Lend1:	cmpult	$5,$21,$25		# compute cy from last add
+	or	$8,$25,$25		# combine cy from the two adds
+	addq	$2,$25,$28		# cy add
+	subq	$6,$28,$22		# 3rd main sub
+	cmpult	$28,$25,$8		# compute cy from last add
+	cmpult	$6,$22,$25		# compute cy from last add
+	stq	$20,0($16)
+	or	$8,$25,$25		# combine cy from the two adds
+	stq	$21,8($16)
+	addq	$3,$25,$28		# cy add
+	subq	$7,$28,$23		# 4th main sub
+	cmpult	$28,$25,$8		# compute cy from last add
+	cmpult	$7,$23,$25		# compute cy from last add
+	or	$8,$25,$25		# combine cy from the two adds
+	addq	$16,32,$16		# update res_ptr
+	stq	$22,-16($16)
+	stq	$23,-8($16)
+.Lend2:	addq	$19,4,$19		# restore loop cnt
+	beq	$19,.Lret
+ # Start software pipeline for 2nd loop
+	ldq	$0,0($18)
+	ldq	$4,0($17)
+	subq	$19,1,$19
+	beq	$19,.Lend0
+ # 2nd loop handles remaining 1-3 limbs
+	.align	4
+.Loop0:	addq	$0,$25,$28		# cy add
+	ldq	$0,8($18)
+	subq	$4,$28,$20		# main sub
+	ldq	$1,8($17)
+	addq	$18,8,$18
+	cmpult	$28,$25,$8		# compute cy from last add
+	addq	$17,8,$17
+	stq	$20,0($16)
+	cmpult	$4,$20,$25		# compute cy from last add
+	subq	$19,1,$19		# decr loop cnt
+	or	$8,$25,$25		# combine cy from the two adds
+	addq	$16,8,$16
+	or	$1,$31,$4
+	bne	$19,.Loop0
+.Lend0:	addq	$0,$25,$28		# cy add
+	subq	$4,$28,$20		# main sub
+	cmpult	$28,$25,$8		# compute cy from last add
+	cmpult	$4,$20,$25		# compute cy from last add
+	stq	$20,0($16)
+	or	$8,$25,$25		# combine cy from the two adds
+
+.Lret:	or	$25,$31,$0		# return cy
+	ret	$31,($26),1
+	.end	__mpn_sub_n