1 # Alpha __mpn_add_n -- Add two limb vectors of the same length > 0 and
2 # store sum in a third limb vector.
3
4 # Copyright (C) 1995-2022 Free Software Foundation, Inc.
5
6 # This file is part of the GNU MP Library.
7
8 # The GNU MP Library is free software; you can redistribute it and/or modify
9 # it under the terms of the GNU Lesser General Public License as published by
10 # the Free Software Foundation; either version 2.1 of the License, or (at your
11 # option) any later version.
12
13 # The GNU MP Library is distributed in the hope that it will be useful, but
14 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16 # License for more details.
17
18 # You should have received a copy of the GNU Lesser General Public License
19 # along with the GNU MP Library. If not, see <https://www.gnu.org/licenses/>.
20
21
22 # INPUT PARAMETERS
23 # res_ptr $16
24 # s1_ptr $17
25 # s2_ptr $18
26 # size $19
27
28 .set noreorder
29 .set noat
30.text
31 .align 3
32 .globl __mpn_add_n
33 .ent __mpn_add_n
34__mpn_add_n:
35 .frame $30,0,$26,0
36
37 or $31,$31,$25 # clear cy
38 subq $19,4,$19 # decr loop cnt
39 blt $19,.Lend2 # if less than 4 limbs, goto 2nd loop
40 # Start software pipeline for 1st loop
41 ldq $0,0($18)
42 ldq $1,8($18)
43 ldq $4,0($17)
44 ldq $5,8($17)
45 addq $17,32,$17 # update s1_ptr
46 ldq $2,16($18)
47 addq $0,$4,$20 # 1st main add
48 ldq $3,24($18)
49 subq $19,4,$19 # decr loop cnt
50 ldq $6,-16($17)
51 cmpult $20,$0,$25 # compute cy from last add
52 ldq $7,-8($17)
53 addq $1,$25,$28 # cy add
54 addq $18,32,$18 # update s2_ptr
55 addq $5,$28,$21 # 2nd main add
56 cmpult $28,$25,$8 # compute cy from last add
57 blt $19,.Lend1 # if less than 4 limbs remain, jump
58 # 1st loop handles groups of 4 limbs in a software pipeline
59 .align 4
60.Loop: cmpult $21,$28,$25 # compute cy from last add
61 ldq $0,0($18)
62 or $8,$25,$25 # combine cy from the two adds
63 ldq $1,8($18)
64 addq $2,$25,$28 # cy add
65 ldq $4,0($17)
66 addq $28,$6,$22 # 3rd main add
67 ldq $5,8($17)
68 cmpult $28,$25,$8 # compute cy from last add
69 cmpult $22,$28,$25 # compute cy from last add
70 stq $20,0($16)
71 or $8,$25,$25 # combine cy from the two adds
72 stq $21,8($16)
73 addq $3,$25,$28 # cy add
74 addq $28,$7,$23 # 4th main add
75 cmpult $28,$25,$8 # compute cy from last add
76 cmpult $23,$28,$25 # compute cy from last add
77 addq $17,32,$17 # update s1_ptr
78 or $8,$25,$25 # combine cy from the two adds
79 addq $16,32,$16 # update res_ptr
80 addq $0,$25,$28 # cy add
81 ldq $2,16($18)
82 addq $4,$28,$20 # 1st main add
83 ldq $3,24($18)
84 cmpult $28,$25,$8 # compute cy from last add
85 ldq $6,-16($17)
86 cmpult $20,$28,$25 # compute cy from last add
87 ldq $7,-8($17)
88 or $8,$25,$25 # combine cy from the two adds
89 subq $19,4,$19 # decr loop cnt
90 stq $22,-16($16)
91 addq $1,$25,$28 # cy add
92 stq $23,-8($16)
93 addq $5,$28,$21 # 2nd main add
94 addq $18,32,$18 # update s2_ptr
95 cmpult $28,$25,$8 # compute cy from last add
96 bge $19,.Loop
97 # Finish software pipeline for 1st loop
98.Lend1: cmpult $21,$28,$25 # compute cy from last add
99 or $8,$25,$25 # combine cy from the two adds
100 addq $2,$25,$28 # cy add
101 addq $28,$6,$22 # 3rd main add
102 cmpult $28,$25,$8 # compute cy from last add
103 cmpult $22,$28,$25 # compute cy from last add
104 stq $20,0($16)
105 or $8,$25,$25 # combine cy from the two adds
106 stq $21,8($16)
107 addq $3,$25,$28 # cy add
108 addq $28,$7,$23 # 4th main add
109 cmpult $28,$25,$8 # compute cy from last add
110 cmpult $23,$28,$25 # compute cy from last add
111 or $8,$25,$25 # combine cy from the two adds
112 addq $16,32,$16 # update res_ptr
113 stq $22,-16($16)
114 stq $23,-8($16)
115.Lend2: addq $19,4,$19 # restore loop cnt
116 beq $19,.Lret
117 # Start software pipeline for 2nd loop
118 ldq $0,0($18)
119 ldq $4,0($17)
120 subq $19,1,$19
121 beq $19,.Lend0
122 # 2nd loop handles remaining 1-3 limbs
123 .align 4
124.Loop0: addq $0,$25,$28 # cy add
125 ldq $0,8($18)
126 addq $4,$28,$20 # main add
127 ldq $4,8($17)
128 addq $18,8,$18
129 cmpult $28,$25,$8 # compute cy from last add
130 addq $17,8,$17
131 stq $20,0($16)
132 cmpult $20,$28,$25 # compute cy from last add
133 subq $19,1,$19 # decr loop cnt
134 or $8,$25,$25 # combine cy from the two adds
135 addq $16,8,$16
136 bne $19,.Loop0
137.Lend0: addq $0,$25,$28 # cy add
138 addq $4,$28,$20 # main add
139 cmpult $28,$25,$8 # compute cy from last add
140 cmpult $20,$28,$25 # compute cy from last add
141 stq $20,0($16)
142 or $8,$25,$25 # combine cy from the two adds
143
144.Lret: or $25,$31,$0 # return cy
145 ret $31,($26),1
146 .end __mpn_add_n
147

source code of glibc/sysdeps/alpha/alphaev5/add_n.S