1 /* SPDX-License-Identifier: GPL-2.0-only */ !! 1 /* SPDX-License-Identifier: GPL-2.0 */
>> 2 /* strlen.S: Sparc optimized strlen code
>> 3 * Hand optimized from GNU libc's strlen
>> 4 * Copyright (C) 1991,1996 Free Software Foundation
>> 5 * Copyright (C) 1996,2008 David S. Miller (davem@davemloft.net)
>> 6 * Copyright (C) 1996, 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
>> 7 */
2 8
>> 9 #include <linux/export.h>
3 #include <linux/linkage.h> 10 #include <linux/linkage.h>
4 #include <asm/asm.h> 11 #include <asm/asm.h>
5 #include <asm/alternative-macros.h> <<
6 #include <asm/hwcap.h> <<
7 <<
8 /* int strlen(const char *s) */ <<
9 SYM_FUNC_START(strlen) <<
10 12
11 ALTERNATIVE("nop", "j strlen_zbb", 0, !! 13 #define LO_MAGIC 0x01010101
>> 14 #define HI_MAGIC 0x80808080
12 15
13 /* !! 16 .text
14 * Returns !! 17 ENTRY(strlen)
15 * a0 - string length !! 18 mov %o0, %o1
16 * !! 19 andcc %o0, 3, %g0
17 * Parameters !! 20 BRANCH32(be, pt, 9f)
18 * a0 - String to measure !! 21 sethi %hi(HI_MAGIC), %o4
19 * !! 22 ldub [%o0], %o5
20 * Clobbers: !! 23 BRANCH_REG_ZERO(pn, %o5, 11f)
21 * t0, t1 !! 24 add %o0, 1, %o0
22 */ !! 25 andcc %o0, 3, %g0
23 mv t1, a0 !! 26 BRANCH32(be, pn, 4f)
24 1: !! 27 or %o4, %lo(HI_MAGIC), %o3
25 lbu t0, 0(t1) !! 28 ldub [%o0], %o5
26 beqz t0, 2f !! 29 BRANCH_REG_ZERO(pn, %o5, 12f)
27 addi t1, t1, 1 !! 30 add %o0, 1, %o0
28 j 1b !! 31 andcc %o0, 3, %g0
>> 32 BRANCH32(be, pt, 5f)
>> 33 sethi %hi(LO_MAGIC), %o4
>> 34 ldub [%o0], %o5
>> 35 BRANCH_REG_ZERO(pn, %o5, 13f)
>> 36 add %o0, 1, %o0
>> 37 BRANCH32(ba, pt, 8f)
>> 38 or %o4, %lo(LO_MAGIC), %o2
>> 39 9:
>> 40 or %o4, %lo(HI_MAGIC), %o3
>> 41 4:
>> 42 sethi %hi(LO_MAGIC), %o4
>> 43 5:
>> 44 or %o4, %lo(LO_MAGIC), %o2
>> 45 8:
>> 46 ld [%o0], %o5
29 2: 47 2:
30 sub a0, t1, a0 !! 48 sub %o5, %o2, %o4
31 ret !! 49 andcc %o4, %o3, %g0
32 !! 50 BRANCH32(be, pt, 8b)
33 /* !! 51 add %o0, 4, %o0
34 * Variant of strlen using the ZBB extension i !! 52
35 */ !! 53 /* Check every byte. */
36 #ifdef CONFIG_RISCV_ISA_ZBB !! 54 srl %o5, 24, %g7
37 strlen_zbb: !! 55 andcc %g7, 0xff, %g0
38 !! 56 BRANCH32(be, pn, 1f)
39 #ifdef CONFIG_CPU_BIG_ENDIAN !! 57 add %o0, -4, %o4
40 # define CZ clz !! 58 srl %o5, 16, %g7
41 # define SHIFT sll !! 59 andcc %g7, 0xff, %g0
42 #else !! 60 BRANCH32(be, pn, 1f)
43 # define CZ ctz !! 61 add %o4, 1, %o4
44 # define SHIFT srl !! 62 srl %o5, 8, %g7
45 #endif !! 63 andcc %g7, 0xff, %g0
46 !! 64 BRANCH32(be, pn, 1f)
47 .option push !! 65 add %o4, 1, %o4
48 .option arch,+zbb !! 66 andcc %o5, 0xff, %g0
49 !! 67 BRANCH32_ANNUL(bne, pt, 2b)
50 /* !! 68 ld [%o0], %o5
51 * Returns !! 69 add %o4, 1, %o4
52 * a0 - string length <<
53 * <<
54 * Parameters <<
55 * a0 - String to measure <<
56 * <<
57 * Clobbers <<
58 * t0, t1, t2, t3 <<
59 */ <<
60 <<
61 /* Number of irrelevant bytes in the f <<
62 andi t2, a0, SZREG-1 <<
63 <<
64 /* Align pointer. */ <<
65 andi t0, a0, -SZREG <<
66 <<
67 li t3, SZREG <<
68 sub t3, t3, t2 <<
69 slli t2, t2, 3 <<
70 <<
71 /* Get the first word. */ <<
72 REG_L t1, 0(t0) <<
73 <<
74 /* <<
75 * Shift away the partial data we load <<
76 * preceding the string with the effec <<
77 * end of the string's first word. <<
78 */ <<
79 SHIFT t1, t1, t2 <<
80 <<
81 /* Convert non-NUL into 0xff and NUL i <<
82 orc.b t1, t1 <<
83 <<
84 /* Convert non-NUL into 0x00 and NUL i <<
85 not t1, t1 <<
86 <<
87 /* <<
88 * Search for the first set bit (corre <<
89 * original chunk). <<
90 */ <<
91 CZ t1, t1 <<
92 <<
93 /* <<
94 * The first chunk is special: compare <<
95 * of valid bytes in this chunk. <<
96 */ <<
97 srli a0, t1, 3 <<
98 bgtu t3, a0, 2f <<
99 <<
100 /* Prepare for the word comparison loo <<
101 addi t2, t0, SZREG <<
102 li t3, -1 <<
103 <<
104 /* <<
105 * Our critical loop is 4 instructions <<
106 * 4 byte or 8 byte chunks. <<
107 */ <<
108 .p2align 3 <<
109 1: 70 1:
110 REG_L t1, SZREG(t0) !! 71 retl
111 addi t0, t0, SZREG !! 72 sub %o4, %o1, %o0
112 orc.b t1, t1 !! 73 11:
113 beq t1, t3, 1b !! 74 retl
114 !! 75 mov 0, %o0
115 not t1, t1 !! 76 12:
116 CZ t1, t1 !! 77 retl
117 srli t1, t1, 3 !! 78 mov 1, %o0
118 !! 79 13:
119 /* Get number of processed bytes. */ !! 80 retl
120 sub t2, t0, t2 !! 81 mov 2, %o0
121 !! 82 ENDPROC(strlen)
122 /* Add number of characters in the fir <<
123 add a0, a0, t2 <<
124 <<
125 /* Add number of characters in the las <<
126 add a0, a0, t1 <<
127 2: <<
128 ret <<
129 <<
130 .option pop <<
131 #endif <<
132 SYM_FUNC_END(strlen) <<
133 SYM_FUNC_ALIAS(__pi_strlen, strlen) <<
134 EXPORT_SYMBOL(strlen) 83 EXPORT_SYMBOL(strlen)
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