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1/*
2 * memscan.S: Optimized memscan for the Sparc.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 */
6
7/* In essence, this is just a fancy strlen. */
8
9#define LO_MAGIC 0x01010101
10#define HI_MAGIC 0x80808080
11
12 .text
13 .align 4
14 .globl __memscan_zero, __memscan_generic
15 .globl memscan
16__memscan_zero:
17 /* %o0 = addr, %o1 = size */
18 cmp %o1, 0
19 bne,a 1f
20 andcc %o0, 3, %g0
21
22 retl
23 nop
24
251:
26 be mzero_scan_word
27 sethi %hi(HI_MAGIC), %g2
28
29 ldsb [%o0], %g3
30mzero_still_not_word_aligned:
31 cmp %g3, 0
32 bne 1f
33 add %o0, 1, %o0
34
35 retl
36 sub %o0, 1, %o0
37
381:
39 subcc %o1, 1, %o1
40 bne,a 1f
41 andcc %o0, 3, %g0
42
43 retl
44 nop
45
461:
47 bne,a mzero_still_not_word_aligned
48 ldsb [%o0], %g3
49
50 sethi %hi(HI_MAGIC), %g2
51mzero_scan_word:
52 or %g2, %lo(HI_MAGIC), %o3
53 sethi %hi(LO_MAGIC), %g3
54 or %g3, %lo(LO_MAGIC), %o2
55mzero_next_word:
56 ld [%o0], %g2
57mzero_next_word_preloaded:
58 sub %g2, %o2, %g2
59mzero_next_word_preloaded_next:
60 andcc %g2, %o3, %g0
61 bne mzero_byte_zero
62 add %o0, 4, %o0
63
64mzero_check_out_of_fuel:
65 subcc %o1, 4, %o1
66 bg,a 1f
67 ld [%o0], %g2
68
69 retl
70 nop
71
721:
73 b mzero_next_word_preloaded_next
74 sub %g2, %o2, %g2
75
76 /* Check every byte. */
77mzero_byte_zero:
78 ldsb [%o0 - 4], %g2
79 cmp %g2, 0
80 bne mzero_byte_one
81 sub %o0, 4, %g3
82
83 retl
84 mov %g3, %o0
85
86mzero_byte_one:
87 ldsb [%o0 - 3], %g2
88 cmp %g2, 0
89 bne,a mzero_byte_two_and_three
90 ldsb [%o0 - 2], %g2
91
92 retl
93 sub %o0, 3, %o0
94
95mzero_byte_two_and_three:
96 cmp %g2, 0
97 bne,a 1f
98 ldsb [%o0 - 1], %g2
99
100 retl
101 sub %o0, 2, %o0
102
1031:
104 cmp %g2, 0
105 bne,a mzero_next_word_preloaded
106 ld [%o0], %g2
107
108 retl
109 sub %o0, 1, %o0
110
111mzero_found_it:
112 retl
113 sub %o0, 2, %o0
114
115memscan:
116__memscan_generic:
117 /* %o0 = addr, %o1 = c, %o2 = size */
118 cmp %o2, 0
119 bne,a 0f
120 ldub [%o0], %g2
121
122 b,a 2f
1231:
124 ldub [%o0], %g2
1250:
126 cmp %g2, %o1
127 be 2f
128 addcc %o2, -1, %o2
129 bne 1b
130 add %o0, 1, %o0
1312:
132 retl
133 nop
1/*
2 * memscan.S: Optimized memscan for the Sparc.
3 *
4 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
5 */
6
7/* In essence, this is just a fancy strlen. */
8
9#define LO_MAGIC 0x01010101
10#define HI_MAGIC 0x80808080
11
12 .text
13 .align 4
14 .globl __memscan_zero, __memscan_generic
15 .globl memscan
16__memscan_zero:
17 /* %o0 = addr, %o1 = size */
18 cmp %o1, 0
19 bne,a 1f
20 andcc %o0, 3, %g0
21
22 retl
23 nop
24
251:
26 be mzero_scan_word
27 sethi %hi(HI_MAGIC), %g2
28
29 ldsb [%o0], %g3
30mzero_still_not_word_aligned:
31 cmp %g3, 0
32 bne 1f
33 add %o0, 1, %o0
34
35 retl
36 sub %o0, 1, %o0
37
381:
39 subcc %o1, 1, %o1
40 bne,a 1f
41 andcc %o0, 3, %g0
42
43 retl
44 nop
45
461:
47 bne,a mzero_still_not_word_aligned
48 ldsb [%o0], %g3
49
50 sethi %hi(HI_MAGIC), %g2
51mzero_scan_word:
52 or %g2, %lo(HI_MAGIC), %o3
53 sethi %hi(LO_MAGIC), %g3
54 or %g3, %lo(LO_MAGIC), %o2
55mzero_next_word:
56 ld [%o0], %g2
57mzero_next_word_preloaded:
58 sub %g2, %o2, %g2
59mzero_next_word_preloaded_next:
60 andcc %g2, %o3, %g0
61 bne mzero_byte_zero
62 add %o0, 4, %o0
63
64mzero_check_out_of_fuel:
65 subcc %o1, 4, %o1
66 bg,a 1f
67 ld [%o0], %g2
68
69 retl
70 nop
71
721:
73 b mzero_next_word_preloaded_next
74 sub %g2, %o2, %g2
75
76 /* Check every byte. */
77mzero_byte_zero:
78 ldsb [%o0 - 4], %g2
79 cmp %g2, 0
80 bne mzero_byte_one
81 sub %o0, 4, %g3
82
83 retl
84 mov %g3, %o0
85
86mzero_byte_one:
87 ldsb [%o0 - 3], %g2
88 cmp %g2, 0
89 bne,a mzero_byte_two_and_three
90 ldsb [%o0 - 2], %g2
91
92 retl
93 sub %o0, 3, %o0
94
95mzero_byte_two_and_three:
96 cmp %g2, 0
97 bne,a 1f
98 ldsb [%o0 - 1], %g2
99
100 retl
101 sub %o0, 2, %o0
102
1031:
104 cmp %g2, 0
105 bne,a mzero_next_word_preloaded
106 ld [%o0], %g2
107
108 retl
109 sub %o0, 1, %o0
110
111mzero_found_it:
112 retl
113 sub %o0, 2, %o0
114
115memscan:
116__memscan_generic:
117 /* %o0 = addr, %o1 = c, %o2 = size */
118 cmp %o2, 0
119 bne,a 0f
120 ldub [%o0], %g2
121
122 b,a 2f
1231:
124 ldub [%o0], %g2
1250:
126 cmp %g2, %o1
127 be 2f
128 addcc %o2, -1, %o2
129 bne 1b
130 add %o0, 1, %o0
1312:
132 retl
133 nop