include/asm-i386/string.h

/* */
This source file includes following definitions.
strcpy
strncpy
strcat
strncat
strcmp
strncmp
strchr
strrchr
strspn
strcspn
strpbrk
strstr
strlen
strtok
__memcpy
__constant_memcpy
memmove
memchr
__memset_generic
__constant_c_memset
__constant_c_and_count_memset
memscan
   1 #ifndef _I386_STRING_H_
   2 #define _I386_STRING_H_
   3 
   4 /*
   5  * This string-include defines all string functions as inline
   6  * functions. Use gcc. It also assumes ds=es=data space, this should be
   7  * normal. Most of the string-functions are rather heavily hand-optimized,
   8  * see especially strtok,strstr,str[c]spn. They should work, but are not
   9  * very easy to understand. Everything is done entirely within the register
  10  * set, making the functions fast and clean. String instructions have been
  11  * used through-out, making for "slightly" unclear code :-)
  12  *
  13  *              Copyright (C) 1991, 1992 Linus Torvalds
  14  */
  15  
  16 extern inline char * strcpy(char * dest,const char *src)
     /*  */
  17 {
  18 __asm__ __volatile__(
  19         "cld\n"
  20         "1:\tlodsb\n\t"
  21         "stosb\n\t"
  22         "testb %%al,%%al\n\t"
  23         "jne 1b"
  24         : /* no output */
  25         :"S" (src),"D" (dest):"si","di","ax","memory");
  26 return dest;
  27 }
  28 
  29 extern inline char * strncpy(char * dest,const char *src,size_t count)
     /*  */
  30 {
  31 __asm__ __volatile__(
  32         "cld\n"
  33         "1:\tdecl %2\n\t"
  34         "js 2f\n\t"
  35         "lodsb\n\t"
  36         "stosb\n\t"
  37         "testb %%al,%%al\n\t"
  38         "jne 1b\n\t"
  39         "rep\n\t"
  40         "stosb\n"
  41         "2:"
  42         : /* no output */
  43         :"S" (src),"D" (dest),"c" (count):"si","di","ax","cx","memory");
  44 return dest;
  45 }
  46 
  47 extern inline char * strcat(char * dest,const char * src)
     /*  */
  48 {
  49 __asm__ __volatile__(
  50         "cld\n\t"
  51         "repne\n\t"
  52         "scasb\n\t"
  53         "decl %1\n"
  54         "1:\tlodsb\n\t"
  55         "stosb\n\t"
  56         "testb %%al,%%al\n\t"
  57         "jne 1b"
  58         : /* no output */
  59         :"S" (src),"D" (dest),"a" (0),"c" (0xffffffff):"si","di","ax","cx");
  60 return dest;
  61 }
  62 
  63 extern inline char * strncat(char * dest,const char * src,size_t count)
     /*  */
  64 {
  65 __asm__ __volatile__(
  66         "cld\n\t"
  67         "repne\n\t"
  68         "scasb\n\t"
  69         "decl %1\n\t"
  70         "movl %4,%3\n"
  71         "1:\tdecl %3\n\t"
  72         "js 2f\n\t"
  73         "lodsb\n\t"
  74         "stosb\n\t"
  75         "testb %%al,%%al\n\t"
  76         "jne 1b\n"
  77         "2:\txorl %2,%2\n\t"
  78         "stosb"
  79         : /* no output */
  80         :"S" (src),"D" (dest),"a" (0),"c" (0xffffffff),"g" (count)
  81         :"si","di","ax","cx","memory");
  82 return dest;
  83 }
  84 
  85 extern inline int strcmp(const char * cs,const char * ct)
     /*  */
  86 {
  87 register int __res;
  88 __asm__ __volatile__(
  89         "cld\n"
  90         "1:\tlodsb\n\t"
  91         "scasb\n\t"
  92         "jne 2f\n\t"
  93         "testb %%al,%%al\n\t"
  94         "jne 1b\n\t"
  95         "xorl %%eax,%%eax\n\t"
  96         "jmp 3f\n"
  97         "2:\tsbbl %%eax,%%eax\n\t"
  98         "orb $1,%%eax\n"
  99         "3:"
 100         :"=a" (__res):"S" (cs),"D" (ct):"si","di");
 101 return __res;
 102 }
 103 
 104 extern inline int strncmp(const char * cs,const char * ct,size_t count)
     /*  */
 105 {
 106 register int __res;
 107 __asm__ __volatile__(
 108         "cld\n"
 109         "1:\tdecl %3\n\t"
 110         "js 2f\n\t"
 111         "lodsb\n\t"
 112         "scasb\n\t"
 113         "jne 3f\n\t"
 114         "testb %%al,%%al\n\t"
 115         "jne 1b\n"
 116         "2:\txorl %%eax,%%eax\n\t"
 117         "jmp 4f\n"
 118         "3:\tsbbl %%eax,%%eax\n\t"
 119         "orb $1,%%al\n"
 120         "4:"
 121         :"=a" (__res):"S" (cs),"D" (ct),"c" (count):"si","di","cx");
 122 return __res;
 123 }
 124 
 125 extern inline char * strchr(const char * s, int c)
     /*  */
 126 {
 127 register char * __res;
 128 __asm__ __volatile__(
 129         "cld\n\t"
 130         "movb %%al,%%ah\n"
 131         "1:\tlodsb\n\t"
 132         "cmpb %%ah,%%al\n\t"
 133         "je 2f\n\t"
 134         "testb %%al,%%al\n\t"
 135         "jne 1b\n\t"
 136         "movl $1,%1\n"
 137         "2:\tmovl %1,%0\n\t"
 138         "decl %0"
 139         :"=a" (__res):"S" (s),"0" (c):"si");
 140 return __res;
 141 }
 142 
 143 extern inline char * strrchr(const char * s, int c)
     /*  */
 144 {
 145 register char * __res;
 146 __asm__ __volatile__(
 147         "cld\n\t"
 148         "movb %%al,%%ah\n"
 149         "1:\tlodsb\n\t"
 150         "cmpb %%ah,%%al\n\t"
 151         "jne 2f\n\t"
 152         "leal -1(%%esi),%0\n"
 153         "2:\ttestb %%al,%%al\n\t"
 154         "jne 1b"
 155         :"=d" (__res):"0" (0),"S" (s),"a" (c):"ax","si");
 156 return __res;
 157 }
 158 
 159 extern inline size_t strspn(const char * cs, const char * ct)
     /*  */
 160 {
 161 register char * __res;
 162 __asm__ __volatile__(
 163         "cld\n\t"
 164         "movl %4,%%edi\n\t"
 165         "repne\n\t"
 166         "scasb\n\t"
 167         "notl %%ecx\n\t"
 168         "decl %%ecx\n\t"
 169         "movl %%ecx,%%edx\n"
 170         "1:\tlodsb\n\t"
 171         "testb %%al,%%al\n\t"
 172         "je 2f\n\t"
 173         "movl %4,%%edi\n\t"
 174         "movl %%edx,%%ecx\n\t"
 175         "repne\n\t"
 176         "scasb\n\t"
 177         "je 1b\n"
 178         "2:\tdecl %0"
 179         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 180         :"ax","cx","dx","di");
 181 return __res-cs;
 182 }
 183 
 184 extern inline size_t strcspn(const char * cs, const char * ct)
     /*  */
 185 {
 186 register char * __res;
 187 __asm__ __volatile__(
 188         "cld\n\t"
 189         "movl %4,%%edi\n\t"
 190         "repne\n\t"
 191         "scasb\n\t"
 192         "notl %%ecx\n\t"
 193         "decl %%ecx\n\t"
 194         "movl %%ecx,%%edx\n"
 195         "1:\tlodsb\n\t"
 196         "testb %%al,%%al\n\t"
 197         "je 2f\n\t"
 198         "movl %4,%%edi\n\t"
 199         "movl %%edx,%%ecx\n\t"
 200         "repne\n\t"
 201         "scasb\n\t"
 202         "jne 1b\n"
 203         "2:\tdecl %0"
 204         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 205         :"ax","cx","dx","di");
 206 return __res-cs;
 207 }
 208 
 209 extern inline char * strpbrk(const char * cs,const char * ct)
     /*  */
 210 {
 211 register char * __res;
 212 __asm__ __volatile__(
 213         "cld\n\t"
 214         "movl %4,%%edi\n\t"
 215         "repne\n\t"
 216         "scasb\n\t"
 217         "notl %%ecx\n\t"
 218         "decl %%ecx\n\t"
 219         "movl %%ecx,%%edx\n"
 220         "1:\tlodsb\n\t"
 221         "testb %%al,%%al\n\t"
 222         "je 2f\n\t"
 223         "movl %4,%%edi\n\t"
 224         "movl %%edx,%%ecx\n\t"
 225         "repne\n\t"
 226         "scasb\n\t"
 227         "jne 1b\n\t"
 228         "decl %0\n\t"
 229         "jmp 3f\n"
 230         "2:\txorl %0,%0\n"
 231         "3:"
 232         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 233         :"ax","cx","dx","di");
 234 return __res;
 235 }
 236 
 237 extern inline char * strstr(const char * cs,const char * ct)
     /*  */
 238 {
 239 register char * __res;
 240 __asm__ __volatile__(
 241         "cld\n\t" \
 242         "movl %4,%%edi\n\t"
 243         "repne\n\t"
 244         "scasb\n\t"
 245         "notl %%ecx\n\t"
 246         "decl %%ecx\n\t"        /* NOTE! This also sets Z if searchstring='' */
 247         "movl %%ecx,%%edx\n"
 248         "1:\tmovl %4,%%edi\n\t"
 249         "movl %%esi,%%eax\n\t"
 250         "movl %%edx,%%ecx\n\t"
 251         "repe\n\t"
 252         "cmpsb\n\t"
 253         "je 2f\n\t"             /* also works for empty string, see above */
 254         "xchgl %%eax,%%esi\n\t"
 255         "incl %%esi\n\t"
 256         "cmpb $0,-1(%%eax)\n\t"
 257         "jne 1b\n\t"
 258         "xorl %%eax,%%eax\n\t"
 259         "2:"
 260         :"=a" (__res):"0" (0),"c" (0xffffffff),"S" (cs),"g" (ct)
 261         :"cx","dx","di","si");
 262 return __res;
 263 }
 264 
 265 extern inline size_t strlen(const char * s)
     /*  */
 266 {
 267 register int __res;
 268 __asm__ __volatile__(
 269         "cld\n\t"
 270         "repne\n\t"
 271         "scasb\n\t"
 272         "notl %0\n\t"
 273         "decl %0"
 274         :"=c" (__res):"D" (s),"a" (0),"0" (0xffffffff):"di");
 275 return __res;
 276 }
 277 
 278 extern char * ___strtok;
 279 
 280 extern inline char * strtok(char * s,const char * ct)
     /*  */
 281 {
 282 register char * __res;
 283 __asm__ __volatile__(
 284         "testl %1,%1\n\t"
 285         "jne 1f\n\t"
 286         "testl %0,%0\n\t"
 287         "je 8f\n\t"
 288         "movl %0,%1\n"
 289         "1:\txorl %0,%0\n\t"
 290         "movl $-1,%%ecx\n\t"
 291         "xorl %%eax,%%eax\n\t"
 292         "cld\n\t"
 293         "movl %4,%%edi\n\t"
 294         "repne\n\t"
 295         "scasb\n\t"
 296         "notl %%ecx\n\t"
 297         "decl %%ecx\n\t"
 298         "je 7f\n\t"                     /* empty delimiter-string */
 299         "movl %%ecx,%%edx\n"
 300         "2:\tlodsb\n\t"
 301         "testb %%al,%%al\n\t"
 302         "je 7f\n\t"
 303         "movl %4,%%edi\n\t"
 304         "movl %%edx,%%ecx\n\t"
 305         "repne\n\t"
 306         "scasb\n\t"
 307         "je 2b\n\t"
 308         "decl %1\n\t"
 309         "cmpb $0,(%1)\n\t"
 310         "je 7f\n\t"
 311         "movl %1,%0\n"
 312         "3:\tlodsb\n\t"
 313         "testb %%al,%%al\n\t"
 314         "je 5f\n\t"
 315         "movl %4,%%edi\n\t"
 316         "movl %%edx,%%ecx\n\t"
 317         "repne\n\t"
 318         "scasb\n\t"
 319         "jne 3b\n\t"
 320         "decl %1\n\t"
 321         "cmpb $0,(%1)\n\t"
 322         "je 5f\n\t"
 323         "movb $0,(%1)\n\t"
 324         "incl %1\n\t"
 325         "jmp 6f\n"
 326         "5:\txorl %1,%1\n"
 327         "6:\tcmpb $0,(%0)\n\t"
 328         "jne 7f\n\t"
 329         "xorl %0,%0\n"
 330         "7:\ttestl %0,%0\n\t"
 331         "jne 8f\n\t"
 332         "movl %0,%1\n"
 333         "8:"
 334         :"=b" (__res),"=S" (___strtok)
 335         :"0" (___strtok),"1" (s),"g" (ct)
 336         :"ax","cx","dx","di","memory");
 337 return __res;
 338 }
 339 
 340 extern inline void * __memcpy(void * to, const void * from, size_t n)
     /*  */
 341 {
 342 __asm__ __volatile__(
 343         "cld\n\t"
 344         "rep ; movsl\n\t"
 345         "testb $2,%b1\n\t"
 346         "je 1f\n\t"
 347         "movsw\n"
 348         "1:\ttestb $1,%b1\n\t"
 349         "je 2f\n\t"
 350         "movsb\n"
 351         "2:"
 352         : /* no output */
 353         :"c" (n/4), "q" (n),"D" ((long) to),"S" ((long) from)
 354         : "cx","di","si","memory");
 355 return (to);
 356 }
 357 
 358 /*
 359  * This looks horribly ugly, but the compiler can optimize it totally,
 360  * as the count is constant.
 361  */
 362 extern inline void * __constant_memcpy(void * to, const void * from, size_t n)
     /*  */
 363 {
 364         switch (n) {
 365                 case 0:
 366                         return to;
 367                 case 1:
 368                         *(unsigned char *)to = *(unsigned char *)from;
 369                         return to;
 370                 case 2:
 371                         *(unsigned short *)to = *(unsigned short *)from;
 372                         return to;
 373                 case 3:
 374                         *(unsigned short *)to = *(unsigned short *)from;
 375                         *(2+(unsigned char *)to) = *(2+(unsigned char *)from);
 376                         return to;
 377                 case 4:
 378                         *(unsigned long *)to = *(unsigned long *)from;
 379                         return to;
 380         }
 381 #define COMMON(x) \
 382 __asm__("cld\n\t" \
 383         "rep ; movsl" \
 384         x \
 385         : /* no outputs */ \
 386         : "c" (n/4),"D" ((long) to),"S" ((long) from) \
 387         : "cx","di","si","memory");
 388 
 389         switch (n % 4) {
 390                 case 0: COMMON(""); return to;
 391                 case 1: COMMON("\n\tmovsb"); return to;
 392                 case 2: COMMON("\n\tmovsw"); return to;
 393                 case 3: COMMON("\n\tmovsw\n\tmovsb"); return to;
 394         }
 395 #undef COMMON
 396 }
 397 
 398 #define memcpy(t, f, n) \
 399 (__builtin_constant_p(n) ? \
 400  __constant_memcpy((t),(f),(n)) : \
 401  __memcpy((t),(f),(n)))
 402 
 403 extern inline void * memmove(void * dest,const void * src, size_t n)
     /*  */
 404 {
 405 if (dest<src)
 406 __asm__ __volatile__(
 407         "cld\n\t"
 408         "rep\n\t"
 409         "movsb"
 410         : /* no output */
 411         :"c" (n),"S" (src),"D" (dest)
 412         :"cx","si","di");
 413 else
 414 __asm__ __volatile__(
 415         "std\n\t"
 416         "rep\n\t"
 417         "movsb\n\t"
 418         "cld"
 419         : /* no output */
 420         :"c" (n),
 421          "S" (n-1+(const char *)src),
 422          "D" (n-1+(char *)dest)
 423         :"cx","si","di","memory");
 424 return dest;
 425 }
 426 
 427 #define memcmp __builtin_memcmp
 428 
 429 extern inline void * memchr(const void * cs,int c,size_t count)
     /*  */
 430 {
 431 register void * __res;
 432 if (!count)
 433         return NULL;
 434 __asm__ __volatile__(
 435         "cld\n\t"
 436         "repne\n\t"
 437         "scasb\n\t"
 438         "je 1f\n\t"
 439         "movl $1,%0\n"
 440         "1:\tdecl %0"
 441         :"=D" (__res):"a" (c),"D" (cs),"c" (count)
 442         :"cx");
 443 return __res;
 444 }
 445 
 446 extern inline void * __memset_generic(void * s, char c,size_t count)
     /*  */
 447 {
 448 __asm__ __volatile__(
 449         "cld\n\t"
 450         "rep\n\t"
 451         "stosb"
 452         : /* no output */
 453         :"a" (c),"D" (s),"c" (count)
 454         :"cx","di","memory");
 455 return s;
 456 }
 457 
 458 /* we might want to write optimized versions of these later */
 459 #define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))
 460 
 461 /*
 462  * memset(x,0,y) is a reasonably common thing to do, so we want to fill
 463  * things 32 bits at a time even when we don't know the size of the
 464  * area at compile-time..
 465  */
 466 extern inline void * __constant_c_memset(void * s, unsigned long c, size_t count)
     /*  */
 467 {
 468 __asm__ __volatile__(
 469         "cld\n\t"
 470         "rep ; stosl\n\t"
 471         "testb $2,%b1\n\t"
 472         "je 1f\n\t"
 473         "stosw\n"
 474         "1:\ttestb $1,%b1\n\t"
 475         "je 2f\n\t"
 476         "stosb\n"
 477         "2:"
 478         : /* no output */
 479         :"a" (c), "q" (count), "c" (count/4), "D" ((long) s)
 480         :"cx","di","memory");
 481 return (s);     
 482 }
 483 
 484 
 485 /*
 486  * This looks horribly ugly, but the compiler can optimize it totally,
 487  * as we by now know that both pattern and count is constant..
 488  */
 489 extern inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
     /*  */
 490 {
 491         switch (count) {
 492                 case 0:
 493                         return s;
 494                 case 1:
 495                         *(unsigned char *)s = pattern;
 496                         return s;
 497                 case 2:
 498                         *(unsigned short *)s = pattern;
 499                         return s;
 500                 case 3:
 501                         *(unsigned short *)s = pattern;
 502                         *(2+(unsigned char *)s) = pattern;
 503                         return s;
 504                 case 4:
 505                         *(unsigned long *)s = pattern;
 506                         return s;
 507         }
 508 #define COMMON(x) \
 509 __asm__("cld\n\t" \
 510         "rep ; stosl" \
 511         x \
 512         : /* no outputs */ \
 513         : "a" (pattern),"c" (count/4),"D" ((long) s) \
 514         : "cx","di","memory")
 515 
 516         switch (count % 4) {
 517                 case 0: COMMON(""); return s;
 518                 case 1: COMMON("\n\tstosb"); return s;
 519                 case 2: COMMON("\n\tstosw"); return s;
 520                 case 3: COMMON("\n\tstosw\n\tstosb"); return s;
 521         }
 522 #undef COMMON
 523 }
 524 
 525 #define __constant_c_x_memset(s, c, count) \
 526 (__builtin_constant_p(count) ? \
 527  __constant_c_and_count_memset((s),(c),(count)) : \
 528  __constant_c_memset((s),(c),(count)))
 529 
 530 #define __memset(s, c, count) \
 531 (__builtin_constant_p(count) ? \
 532  __constant_count_memset((s),(c),(count)) : \
 533  __memset_generic((s),(c),(count)))
 534 
 535 #define memset(s, c, count) \
 536 (__builtin_constant_p(c) ? \
 537  __constant_c_x_memset((s),(0x01010101UL*(unsigned char)c),(count)) : \
 538  __memset((s),(c),(count)))
 539 
 540 /*
 541  * find the first occurrence of byte 'c', or 1 past the area if none
 542  */
 543 extern inline void * memscan(void * addr, int c, size_t size)
     /*  */
 544 {
 545         if (!size)
 546                 return addr;
 547         __asm__("cld
 548                 repnz; scasb
 549                 jnz 1f
 550                 dec %%edi
 551 1:              "
 552                 : "=D" (addr), "=c" (size)
 553                 : "0" (addr), "1" (size), "a" (c));
 554         return addr;
 555 }
 556 
 557 #endif
/* */
root/include/asm-i386/string.h

INCLUDED FROM

DEFINITIONS
