1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * memscan.S: Optimized memscan for the Sparc.
4 *
5 * Copyright (C) 1996 David S. Miller (davem@c
6 */
7
8 #include <linux/export.h>
9
10 /* In essence, this is just a fancy strlen. */
11
12 #define LO_MAGIC 0x01010101
13 #define HI_MAGIC 0x80808080
14
15 .text
16 .align 4
17 .globl __memscan_zero, __memscan_gene
18 .globl memscan
19 EXPORT_SYMBOL(__memscan_zero)
20 EXPORT_SYMBOL(__memscan_generic)
21 __memscan_zero:
22 /* %o0 = addr, %o1 = size */
23 cmp %o1, 0
24 bne,a 1f
25 andcc %o0, 3, %g0
26
27 retl
28 nop
29
30 1:
31 be mzero_scan_word
32 sethi %hi(HI_MAGIC), %g2
33
34 ldsb [%o0], %g3
35 mzero_still_not_word_aligned:
36 cmp %g3, 0
37 bne 1f
38 add %o0, 1, %o0
39
40 retl
41 sub %o0, 1, %o0
42
43 1:
44 subcc %o1, 1, %o1
45 bne,a 1f
46 andcc %o0, 3, %g0
47
48 retl
49 nop
50
51 1:
52 bne,a mzero_still_not_word_aligned
53 ldsb [%o0], %g3
54
55 sethi %hi(HI_MAGIC), %g2
56 mzero_scan_word:
57 or %g2, %lo(HI_MAGIC), %o3
58 sethi %hi(LO_MAGIC), %g3
59 or %g3, %lo(LO_MAGIC), %o2
60 mzero_next_word:
61 ld [%o0], %g2
62 mzero_next_word_preloaded:
63 sub %g2, %o2, %g2
64 mzero_next_word_preloaded_next:
65 andcc %g2, %o3, %g0
66 bne mzero_byte_zero
67 add %o0, 4, %o0
68
69 mzero_check_out_of_fuel:
70 subcc %o1, 4, %o1
71 bg,a 1f
72 ld [%o0], %g2
73
74 retl
75 nop
76
77 1:
78 b mzero_next_word_preloaded_next
79 sub %g2, %o2, %g2
80
81 /* Check every byte. */
82 mzero_byte_zero:
83 ldsb [%o0 - 4], %g2
84 cmp %g2, 0
85 bne mzero_byte_one
86 sub %o0, 4, %g3
87
88 retl
89 mov %g3, %o0
90
91 mzero_byte_one:
92 ldsb [%o0 - 3], %g2
93 cmp %g2, 0
94 bne,a mzero_byte_two_and_three
95 ldsb [%o0 - 2], %g2
96
97 retl
98 sub %o0, 3, %o0
99
100 mzero_byte_two_and_three:
101 cmp %g2, 0
102 bne,a 1f
103 ldsb [%o0 - 1], %g2
104
105 retl
106 sub %o0, 2, %o0
107
108 1:
109 cmp %g2, 0
110 bne,a mzero_next_word_preloaded
111 ld [%o0], %g2
112
113 retl
114 sub %o0, 1, %o0
115
116 mzero_found_it:
117 retl
118 sub %o0, 2, %o0
119
120 memscan:
121 __memscan_generic:
122 /* %o0 = addr, %o1 = c, %o2 = size */
123 cmp %o2, 0
124 bne,a 0f
125 ldub [%o0], %g2
126
127 b,a 2f
128 1:
129 ldub [%o0], %g2
130 0:
131 cmp %g2, %o1
132 be 2f
133 addcc %o2, -1, %o2
134 bne 1b
135 add %o0, 1, %o0
136 2:
137 retl
138 nop
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