about summary refs log tree commit diff
path: root/sysdeps/alpha/alphaev5/sub_n.S
blob: c24e6ae67fab287aac19555dff34450b13bf3c8b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
 # Alpha __mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
 # store difference in a third limb vector.

 # Copyright (C) 1995-2021 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 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.

 # 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 Lesser General Public
 # License for more details.

 # You should have received a copy of the GNU Lesser General Public License
 # along with the GNU MP Library.  If not, see <https://www.gnu.org/licenses/>.


 # 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