The Android Open Source Project | 5b1eb06 | 2009-03-03 19:29:32 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Taken from Linux /usr/include/asm/string.h |
| 3 | * All except memcpy, memmove, memset and memcmp removed. |
| 4 | */ |
| 5 | |
| 6 | #ifndef _I386_STRING_H_ |
| 7 | #define _I386_STRING_H_ |
| 8 | |
| 9 | /* |
| 10 | * This string-include defines all string functions as inline |
| 11 | * functions. Use gcc. It also assumes ds=es=data space, this should be |
| 12 | * normal. Most of the string-functions are rather heavily hand-optimized, |
| 13 | * see especially strtok,strstr,str[c]spn. They should work, but are not |
| 14 | * very easy to understand. Everything is done entirely within the register |
| 15 | * set, making the functions fast and clean. String instructions have been |
| 16 | * used through-out, making for "slightly" unclear code :-) |
| 17 | * |
| 18 | * NO Copyright (C) 1991, 1992 Linus Torvalds, |
| 19 | * consider these trivial functions to be PD. |
| 20 | */ |
| 21 | |
| 22 | typedef int size_t; |
| 23 | |
| 24 | extern void *__memcpy(void * to, const void * from, size_t n); |
| 25 | extern void *__constant_memcpy(void * to, const void * from, size_t n); |
| 26 | extern void *memmove(void * dest,const void * src, size_t n); |
| 27 | extern void *__memset_generic(void * s, char c,size_t count); |
| 28 | extern void *__constant_c_memset(void * s, unsigned long c, size_t count); |
| 29 | extern void *__constant_c_and_count_memset(void * s, unsigned long pattern, size_t count); |
| 30 | |
| 31 | |
| 32 | extern inline void * __memcpy(void * to, const void * from, size_t n) |
| 33 | { |
| 34 | int d0, d1, d2; |
| 35 | __asm__ __volatile__( |
| 36 | "cld\n\t" |
| 37 | "rep ; movsl\n\t" |
| 38 | "testb $2,%b4\n\t" |
| 39 | "je 1f\n\t" |
| 40 | "movsw\n" |
| 41 | "1:\ttestb $1,%b4\n\t" |
| 42 | "je 2f\n\t" |
| 43 | "movsb\n" |
| 44 | "2:" |
| 45 | : "=&c" (d0), "=&D" (d1), "=&S" (d2) |
| 46 | :"0" (n/4), "q" (n),"1" ((long) to),"2" ((long) from) |
| 47 | : "memory"); |
| 48 | return (to); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * This looks horribly ugly, but the compiler can optimize it totally, |
| 53 | * as the count is constant. |
| 54 | */ |
| 55 | extern inline void * __constant_memcpy(void * to, const void * from, size_t n) |
| 56 | { |
| 57 | switch (n) { |
| 58 | case 0: |
| 59 | return to; |
| 60 | case 1: |
| 61 | *(unsigned char *)to = *(const unsigned char *)from; |
| 62 | return to; |
| 63 | case 2: |
| 64 | *(unsigned short *)to = *(const unsigned short *)from; |
| 65 | return to; |
| 66 | case 3: |
| 67 | *(unsigned short *)to = *(const unsigned short *)from; |
| 68 | *(2+(unsigned char *)to) = *(2+(const unsigned char *)from); |
| 69 | return to; |
| 70 | case 4: |
| 71 | *(unsigned long *)to = *(const unsigned long *)from; |
| 72 | return to; |
| 73 | case 6: /* for Ethernet addresses */ |
| 74 | *(unsigned long *)to = *(const unsigned long *)from; |
| 75 | *(2+(unsigned short *)to) = *(2+(const unsigned short *)from); |
| 76 | return to; |
| 77 | case 8: |
| 78 | *(unsigned long *)to = *(const unsigned long *)from; |
| 79 | *(1+(unsigned long *)to) = *(1+(const unsigned long *)from); |
| 80 | return to; |
| 81 | case 12: |
| 82 | *(unsigned long *)to = *(const unsigned long *)from; |
| 83 | *(1+(unsigned long *)to) = *(1+(const unsigned long *)from); |
| 84 | *(2+(unsigned long *)to) = *(2+(const unsigned long *)from); |
| 85 | return to; |
| 86 | case 16: |
| 87 | *(unsigned long *)to = *(const unsigned long *)from; |
| 88 | *(1+(unsigned long *)to) = *(1+(const unsigned long *)from); |
| 89 | *(2+(unsigned long *)to) = *(2+(const unsigned long *)from); |
| 90 | *(3+(unsigned long *)to) = *(3+(const unsigned long *)from); |
| 91 | return to; |
| 92 | case 20: |
| 93 | *(unsigned long *)to = *(const unsigned long *)from; |
| 94 | *(1+(unsigned long *)to) = *(1+(const unsigned long *)from); |
| 95 | *(2+(unsigned long *)to) = *(2+(const unsigned long *)from); |
| 96 | *(3+(unsigned long *)to) = *(3+(const unsigned long *)from); |
| 97 | *(4+(unsigned long *)to) = *(4+(const unsigned long *)from); |
| 98 | return to; |
| 99 | } |
| 100 | #define COMMON(x) \ |
| 101 | __asm__ __volatile__( \ |
| 102 | "cld\n\t" \ |
| 103 | "rep ; movsl" \ |
| 104 | x \ |
| 105 | : "=&c" (d0), "=&D" (d1), "=&S" (d2) \ |
| 106 | : "0" (n/4),"1" ((long) to),"2" ((long) from) \ |
| 107 | : "memory"); |
| 108 | { |
| 109 | int d0, d1, d2; |
| 110 | switch (n % 4) { |
| 111 | case 0: COMMON(""); return to; |
| 112 | case 1: COMMON("\n\tmovsb"); return to; |
| 113 | case 2: COMMON("\n\tmovsw"); return to; |
| 114 | default: COMMON("\n\tmovsw\n\tmovsb"); return to; |
| 115 | } |
| 116 | } |
| 117 | |
| 118 | #undef COMMON |
| 119 | } |
| 120 | |
| 121 | #define __HAVE_ARCH_MEMCPY |
| 122 | #define memcpy(t, f, n) \ |
| 123 | (__builtin_constant_p(n) ? \ |
| 124 | __constant_memcpy((t),(f),(n)) : \ |
| 125 | __memcpy((t),(f),(n))) |
| 126 | |
| 127 | #define __HAVE_ARCH_MEMMOVE |
| 128 | extern inline void * memmove(void * dest,const void * src, size_t n) |
| 129 | { |
| 130 | int d0, d1, d2; |
| 131 | if (dest<src) |
| 132 | __asm__ __volatile__( |
| 133 | "cld\n\t" |
| 134 | "rep\n\t" |
| 135 | "movsb" |
| 136 | : "=&c" (d0), "=&S" (d1), "=&D" (d2) |
| 137 | :"0" (n),"1" (src),"2" (dest) |
| 138 | : "memory"); |
| 139 | else |
| 140 | __asm__ __volatile__( |
| 141 | "std\n\t" |
| 142 | "rep\n\t" |
| 143 | "movsb\n\t" |
| 144 | "cld" |
| 145 | : "=&c" (d0), "=&S" (d1), "=&D" (d2) |
| 146 | :"0" (n), |
| 147 | "1" (n-1+(const char *)src), |
| 148 | "2" (n-1+(char *)dest) |
| 149 | :"memory"); |
| 150 | return dest; |
| 151 | } |
| 152 | |
| 153 | #define memcmp __builtin_memcmp |
| 154 | |
| 155 | extern inline void * __memset_generic(void * s, char c,size_t count) |
| 156 | { |
| 157 | int d0, d1; |
| 158 | __asm__ __volatile__( |
| 159 | "cld\n\t" |
| 160 | "rep\n\t" |
| 161 | "stosb" |
| 162 | : "=&c" (d0), "=&D" (d1) |
| 163 | :"a" (c),"1" (s),"0" (count) |
| 164 | :"memory"); |
| 165 | return s; |
| 166 | } |
| 167 | |
| 168 | /* we might want to write optimized versions of these later */ |
| 169 | #define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count)) |
| 170 | |
| 171 | /* |
| 172 | * memset(x,0,y) is a reasonably common thing to do, so we want to fill |
| 173 | * things 32 bits at a time even when we don't know the size of the |
| 174 | * area at compile-time.. |
| 175 | */ |
| 176 | extern inline void * __constant_c_memset(void * s, unsigned long c, size_t count) |
| 177 | { |
| 178 | int d0, d1; |
| 179 | __asm__ __volatile__( |
| 180 | "cld\n\t" |
| 181 | "rep ; stosl\n\t" |
| 182 | "testb $2,%b3\n\t" |
| 183 | "je 1f\n\t" |
| 184 | "stosw\n" |
| 185 | "1:\ttestb $1,%b3\n\t" |
| 186 | "je 2f\n\t" |
| 187 | "stosb\n" |
| 188 | "2:" |
| 189 | : "=&c" (d0), "=&D" (d1) |
| 190 | :"a" (c), "q" (count), "0" (count/4), "1" ((long) s) |
| 191 | :"memory"); |
| 192 | return (s); |
| 193 | } |
| 194 | |
| 195 | /* |
| 196 | * This looks horribly ugly, but the compiler can optimize it totally, |
| 197 | * as we by now know that both pattern and count is constant.. |
| 198 | */ |
| 199 | extern inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count) |
| 200 | { |
| 201 | switch (count) { |
| 202 | case 0: |
| 203 | return s; |
| 204 | case 1: |
| 205 | *(unsigned char *)s = pattern; |
| 206 | return s; |
| 207 | case 2: |
| 208 | *(unsigned short *)s = pattern; |
| 209 | return s; |
| 210 | case 3: |
| 211 | *(unsigned short *)s = pattern; |
| 212 | *(2+(unsigned char *)s) = pattern; |
| 213 | return s; |
| 214 | case 4: |
| 215 | *(unsigned long *)s = pattern; |
| 216 | return s; |
| 217 | } |
| 218 | #define COMMON(x) \ |
| 219 | __asm__ __volatile__("cld\n\t" \ |
| 220 | "rep ; stosl" \ |
| 221 | x \ |
| 222 | : "=&c" (d0), "=&D" (d1) \ |
| 223 | : "a" (pattern),"0" (count/4),"1" ((long) s) \ |
| 224 | : "memory") |
| 225 | { |
| 226 | int d0, d1; |
| 227 | switch (count % 4) { |
| 228 | case 0: COMMON(""); return s; |
| 229 | case 1: COMMON("\n\tstosb"); return s; |
| 230 | case 2: COMMON("\n\tstosw"); return s; |
| 231 | default: COMMON("\n\tstosw\n\tstosb"); return s; |
| 232 | } |
| 233 | } |
| 234 | |
| 235 | #undef COMMON |
| 236 | } |
| 237 | |
| 238 | #define __constant_c_x_memset(s, c, count) \ |
| 239 | (__builtin_constant_p(count) ? \ |
| 240 | __constant_c_and_count_memset((s),(c),(count)) : \ |
| 241 | __constant_c_memset((s),(c),(count))) |
| 242 | |
| 243 | #define __memset(s, c, count) \ |
| 244 | (__builtin_constant_p(count) ? \ |
| 245 | __constant_count_memset((s),(c),(count)) : \ |
| 246 | __memset_generic((s),(c),(count))) |
| 247 | |
| 248 | #define __HAVE_ARCH_MEMSET |
| 249 | #define memset(s, c, count) \ |
| 250 | (__builtin_constant_p(c) ? \ |
| 251 | __constant_c_x_memset((s),(c),(count)) : \ |
| 252 | __memset((s),(c),(count))) |
| 253 | |
| 254 | #define __HAVE_ARCH_STRNCMP |
| 255 | static inline int strncmp(const char * cs,const char * ct,size_t count) |
| 256 | { |
| 257 | register int __res; |
| 258 | int d0, d1, d2; |
| 259 | __asm__ __volatile__( |
| 260 | "1:\tdecl %3\n\t" |
| 261 | "js 2f\n\t" |
| 262 | "lodsb\n\t" |
| 263 | "scasb\n\t" |
| 264 | "jne 3f\n\t" |
| 265 | "testb %%al,%%al\n\t" |
| 266 | "jne 1b\n" |
| 267 | "2:\txorl %%eax,%%eax\n\t" |
| 268 | "jmp 4f\n" |
| 269 | "3:\tsbbl %%eax,%%eax\n\t" |
| 270 | "orb $1,%%al\n" |
| 271 | "4:" |
| 272 | :"=a" (__res), "=&S" (d0), "=&D" (d1), "=&c" (d2) |
| 273 | :"1" (cs),"2" (ct),"3" (count)); |
| 274 | return __res; |
| 275 | } |
| 276 | |
| 277 | #define __HAVE_ARCH_STRLEN |
| 278 | static inline size_t strlen(const char * s) |
| 279 | { |
| 280 | int d0; |
| 281 | register int __res; |
| 282 | __asm__ __volatile__( |
| 283 | "repne\n\t" |
| 284 | "scasb\n\t" |
| 285 | "notl %0\n\t" |
| 286 | "decl %0" |
| 287 | :"=c" (__res), "=&D" (d0) :"1" (s),"a" (0), "0" (0xffffffff)); |
| 288 | return __res; |
| 289 | } |
| 290 | |
| 291 | #endif |