1/* MIPS __mpn_submul_1 -- Multiply a limb vector with a single limb and
2subtract the product from a second limb vector.
3
4Copyright (C) 1995-2022 Free Software Foundation, Inc.
5
6This file is part of the GNU MP Library.
7
8The GNU MP Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 2.1 of the License, or (at your
11option) any later version.
12
13The GNU MP Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MP Library. If not, see
20<https://www.gnu.org/licenses/>. */
21
22#include <sysdep.h>
23
24/* INPUT PARAMETERS
25 res_ptr $4
26 s1_ptr $5
27 size $6
28 s2_limb $7
29*/
30#ifdef __PIC__
31 .option pic2
32#endif
33ENTRY (__mpn_submul_1)
34 .set noreorder
35#ifdef __PIC__
36 .cpload t9
37#endif
38 .set nomacro
39
40 /* warm up phase 0 */
41 lw $8,0($5)
42
43 /* warm up phase 1 */
44 addiu $5,$5,4
45#if __mips_isa_rev < 6
46 multu $8,$7
47#else
48 mulu $11,$8,$7
49 muhu $12,$8,$7
50#endif
51
52 addiu $6,$6,-1
53 beq $6,$0,L(LC0)
54 move $2,$0 /* zero cy2 */
55
56 addiu $6,$6,-1
57 beq $6,$0,L(LC1)
58 lw $8,0($5) /* load new s1 limb as early as possible */
59
60L(Loop): lw $10,0($4)
61#if __mips_isa_rev < 6
62 mflo $3
63 mfhi $9
64#else
65 move $3,$11
66 move $9,$12
67#endif
68 addiu $5,$5,4
69 addu $3,$3,$2 /* add old carry limb to low product limb */
70#if __mips_isa_rev < 6
71 multu $8,$7
72#else
73 mulu $11,$8,$7
74 muhu $12,$8,$7
75#endif
76 lw $8,0($5) /* load new s1 limb as early as possible */
77 addiu $6,$6,-1 /* decrement loop counter */
78 sltu $2,$3,$2 /* carry from previous addition -> $2 */
79 subu $3,$10,$3
80 sgtu $10,$3,$10
81 addu $2,$2,$10
82 sw $3,0($4)
83 addiu $4,$4,4
84 bne $6,$0,L(Loop) /* should be "bnel" */
85 addu $2,$9,$2 /* add high product limb and carry from addition */
86
87 /* cool down phase 1 */
88L(LC1): lw $10,0($4)
89#if __mips_isa_rev < 6
90 mflo $3
91 mfhi $9
92#else
93 move $3,$11
94 move $9,$12
95#endif
96 addu $3,$3,$2
97 sltu $2,$3,$2
98#if __mips_isa_rev < 6
99 multu $8,$7
100#else
101 mulu $11,$8,$7
102 muhu $12,$8,$7
103#endif
104 subu $3,$10,$3
105 sgtu $10,$3,$10
106 addu $2,$2,$10
107 sw $3,0($4)
108 addiu $4,$4,4
109 addu $2,$9,$2 /* add high product limb and carry from addition */
110
111 /* cool down phase 0 */
112L(LC0): lw $10,0($4)
113#if __mips_isa_rev < 6
114 mflo $3
115 mfhi $9
116#else
117 move $3,$11
118 move $9,$12
119#endif
120 addu $3,$3,$2
121 sltu $2,$3,$2
122 subu $3,$10,$3
123 sgtu $10,$3,$10
124 addu $2,$2,$10
125 sw $3,0($4)
126 j $31
127 addu $2,$9,$2 /* add high product limb and carry from addition */
128 END (__mpn_submul_1)
129

source code of glibc/sysdeps/mips/submul_1.S