Commit | Line | Data |
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b520b85a AK |
1 | /* |
2 | * Most of the string-functions are rather heavily hand-optimized, | |
3 | * see especially strsep,strstr,str[c]spn. They should work, but are not | |
4 | * very easy to understand. Everything is done entirely within the register | |
5 | * set, making the functions fast and clean. String instructions have been | |
6 | * used through-out, making for "slightly" unclear code :-) | |
7 | * | |
8 | * AK: On P4 and K7 using non string instruction implementations might be faster | |
9 | * for large memory blocks. But most of them are unlikely to be used on large | |
10 | * strings. | |
11 | */ | |
12 | ||
13 | #include <linux/string.h> | |
14 | #include <linux/module.h> | |
15 | ||
16 | #ifdef __HAVE_ARCH_STRCPY | |
8cf36d2b | 17 | char *strcpy(char *dest, const char *src) |
b520b85a AK |
18 | { |
19 | int d0, d1, d2; | |
8cf36d2b | 20 | asm volatile("1:\tlodsb\n\t" |
b520b85a AK |
21 | "stosb\n\t" |
22 | "testb %%al,%%al\n\t" | |
23 | "jne 1b" | |
24 | : "=&S" (d0), "=&D" (d1), "=&a" (d2) | |
3492cdf0 | 25 | : "0" (src), "1" (dest) : "memory"); |
b520b85a AK |
26 | return dest; |
27 | } | |
28 | EXPORT_SYMBOL(strcpy); | |
29 | #endif | |
30 | ||
31 | #ifdef __HAVE_ARCH_STRNCPY | |
8cf36d2b | 32 | char *strncpy(char *dest, const char *src, size_t count) |
b520b85a AK |
33 | { |
34 | int d0, d1, d2, d3; | |
8cf36d2b | 35 | asm volatile("1:\tdecl %2\n\t" |
b520b85a AK |
36 | "js 2f\n\t" |
37 | "lodsb\n\t" | |
38 | "stosb\n\t" | |
39 | "testb %%al,%%al\n\t" | |
40 | "jne 1b\n\t" | |
41 | "rep\n\t" | |
42 | "stosb\n" | |
43 | "2:" | |
44 | : "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3) | |
3492cdf0 | 45 | : "0" (src), "1" (dest), "2" (count) : "memory"); |
b520b85a AK |
46 | return dest; |
47 | } | |
48 | EXPORT_SYMBOL(strncpy); | |
49 | #endif | |
50 | ||
51 | #ifdef __HAVE_ARCH_STRCAT | |
8cf36d2b | 52 | char *strcat(char *dest, const char *src) |
b520b85a AK |
53 | { |
54 | int d0, d1, d2, d3; | |
8cf36d2b | 55 | asm volatile("repne\n\t" |
b520b85a AK |
56 | "scasb\n\t" |
57 | "decl %1\n" | |
58 | "1:\tlodsb\n\t" | |
59 | "stosb\n\t" | |
60 | "testb %%al,%%al\n\t" | |
61 | "jne 1b" | |
62 | : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3) | |
3492cdf0 | 63 | : "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu) : "memory"); |
b520b85a AK |
64 | return dest; |
65 | } | |
66 | EXPORT_SYMBOL(strcat); | |
67 | #endif | |
68 | ||
69 | #ifdef __HAVE_ARCH_STRNCAT | |
8cf36d2b | 70 | char *strncat(char *dest, const char *src, size_t count) |
b520b85a AK |
71 | { |
72 | int d0, d1, d2, d3; | |
8cf36d2b | 73 | asm volatile("repne\n\t" |
b520b85a AK |
74 | "scasb\n\t" |
75 | "decl %1\n\t" | |
76 | "movl %8,%3\n" | |
77 | "1:\tdecl %3\n\t" | |
78 | "js 2f\n\t" | |
79 | "lodsb\n\t" | |
80 | "stosb\n\t" | |
81 | "testb %%al,%%al\n\t" | |
82 | "jne 1b\n" | |
83 | "2:\txorl %2,%2\n\t" | |
84 | "stosb" | |
85 | : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3) | |
8cf36d2b | 86 | : "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu), "g" (count) |
b520b85a AK |
87 | : "memory"); |
88 | return dest; | |
89 | } | |
90 | EXPORT_SYMBOL(strncat); | |
91 | #endif | |
92 | ||
93 | #ifdef __HAVE_ARCH_STRCMP | |
8cf36d2b | 94 | int strcmp(const char *cs, const char *ct) |
b520b85a AK |
95 | { |
96 | int d0, d1; | |
97 | int res; | |
8cf36d2b | 98 | asm volatile("1:\tlodsb\n\t" |
b520b85a AK |
99 | "scasb\n\t" |
100 | "jne 2f\n\t" | |
101 | "testb %%al,%%al\n\t" | |
102 | "jne 1b\n\t" | |
103 | "xorl %%eax,%%eax\n\t" | |
104 | "jmp 3f\n" | |
105 | "2:\tsbbl %%eax,%%eax\n\t" | |
106 | "orb $1,%%al\n" | |
107 | "3:" | |
3492cdf0 PC |
108 | : "=a" (res), "=&S" (d0), "=&D" (d1) |
109 | : "1" (cs), "2" (ct) | |
110 | : "memory"); | |
b520b85a AK |
111 | return res; |
112 | } | |
113 | EXPORT_SYMBOL(strcmp); | |
114 | #endif | |
115 | ||
116 | #ifdef __HAVE_ARCH_STRNCMP | |
8cf36d2b | 117 | int strncmp(const char *cs, const char *ct, size_t count) |
b520b85a AK |
118 | { |
119 | int res; | |
120 | int d0, d1, d2; | |
8cf36d2b | 121 | asm volatile("1:\tdecl %3\n\t" |
b520b85a AK |
122 | "js 2f\n\t" |
123 | "lodsb\n\t" | |
124 | "scasb\n\t" | |
125 | "jne 3f\n\t" | |
126 | "testb %%al,%%al\n\t" | |
127 | "jne 1b\n" | |
128 | "2:\txorl %%eax,%%eax\n\t" | |
129 | "jmp 4f\n" | |
130 | "3:\tsbbl %%eax,%%eax\n\t" | |
131 | "orb $1,%%al\n" | |
132 | "4:" | |
3492cdf0 PC |
133 | : "=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2) |
134 | : "1" (cs), "2" (ct), "3" (count) | |
135 | : "memory"); | |
b520b85a AK |
136 | return res; |
137 | } | |
138 | EXPORT_SYMBOL(strncmp); | |
139 | #endif | |
140 | ||
141 | #ifdef __HAVE_ARCH_STRCHR | |
8cf36d2b | 142 | char *strchr(const char *s, int c) |
b520b85a AK |
143 | { |
144 | int d0; | |
8cf36d2b PC |
145 | char *res; |
146 | asm volatile("movb %%al,%%ah\n" | |
b520b85a AK |
147 | "1:\tlodsb\n\t" |
148 | "cmpb %%ah,%%al\n\t" | |
149 | "je 2f\n\t" | |
150 | "testb %%al,%%al\n\t" | |
151 | "jne 1b\n\t" | |
152 | "movl $1,%1\n" | |
153 | "2:\tmovl %1,%0\n\t" | |
154 | "decl %0" | |
3492cdf0 PC |
155 | : "=a" (res), "=&S" (d0) |
156 | : "1" (s), "0" (c) | |
157 | : "memory"); | |
b520b85a AK |
158 | return res; |
159 | } | |
160 | EXPORT_SYMBOL(strchr); | |
161 | #endif | |
162 | ||
b520b85a | 163 | #ifdef __HAVE_ARCH_STRLEN |
8cf36d2b | 164 | size_t strlen(const char *s) |
b520b85a AK |
165 | { |
166 | int d0; | |
890890cb | 167 | size_t res; |
8cf36d2b | 168 | asm volatile("repne\n\t" |
890890cb | 169 | "scasb" |
3492cdf0 PC |
170 | : "=c" (res), "=&D" (d0) |
171 | : "1" (s), "a" (0), "0" (0xffffffffu) | |
172 | : "memory"); | |
890890cb | 173 | return ~res - 1; |
b520b85a AK |
174 | } |
175 | EXPORT_SYMBOL(strlen); | |
176 | #endif | |
177 | ||
178 | #ifdef __HAVE_ARCH_MEMCHR | |
8cf36d2b | 179 | void *memchr(const void *cs, int c, size_t count) |
b520b85a AK |
180 | { |
181 | int d0; | |
182 | void *res; | |
183 | if (!count) | |
184 | return NULL; | |
8cf36d2b | 185 | asm volatile("repne\n\t" |
b520b85a AK |
186 | "scasb\n\t" |
187 | "je 1f\n\t" | |
188 | "movl $1,%0\n" | |
189 | "1:\tdecl %0" | |
3492cdf0 PC |
190 | : "=D" (res), "=&c" (d0) |
191 | : "a" (c), "0" (cs), "1" (count) | |
192 | : "memory"); | |
b520b85a AK |
193 | return res; |
194 | } | |
195 | EXPORT_SYMBOL(memchr); | |
196 | #endif | |
197 | ||
198 | #ifdef __HAVE_ARCH_MEMSCAN | |
8cf36d2b | 199 | void *memscan(void *addr, int c, size_t size) |
b520b85a AK |
200 | { |
201 | if (!size) | |
202 | return addr; | |
203 | asm volatile("repnz; scasb\n\t" | |
204 | "jnz 1f\n\t" | |
205 | "dec %%edi\n" | |
206 | "1:" | |
207 | : "=D" (addr), "=c" (size) | |
208 | : "0" (addr), "1" (size), "a" (c) | |
209 | : "memory"); | |
210 | return addr; | |
211 | } | |
212 | EXPORT_SYMBOL(memscan); | |
213 | #endif | |
214 | ||
215 | #ifdef __HAVE_ARCH_STRNLEN | |
216 | size_t strnlen(const char *s, size_t count) | |
217 | { | |
218 | int d0; | |
219 | int res; | |
8cf36d2b | 220 | asm volatile("movl %2,%0\n\t" |
b520b85a AK |
221 | "jmp 2f\n" |
222 | "1:\tcmpb $0,(%0)\n\t" | |
223 | "je 3f\n\t" | |
224 | "incl %0\n" | |
225 | "2:\tdecl %1\n\t" | |
226 | "cmpl $-1,%1\n\t" | |
227 | "jne 1b\n" | |
228 | "3:\tsubl %2,%0" | |
3492cdf0 PC |
229 | : "=a" (res), "=&d" (d0) |
230 | : "c" (s), "1" (count) | |
231 | : "memory"); | |
b520b85a AK |
232 | return res; |
233 | } | |
234 | EXPORT_SYMBOL(strnlen); | |
235 | #endif |