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
strnlen
__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 #define __HAVE_ARCH_STRCPY
  17 extern inline char * strcpy(char * dest,const char *src)
     /*  */
  18 {
  19 __asm__ __volatile__(
  20         "cld\n"
  21         "1:\tlodsb\n\t"
  22         "stosb\n\t"
  23         "testb %%al,%%al\n\t"
  24         "jne 1b"
  25         : /* no output */
  26         :"S" (src),"D" (dest):"si","di","ax","memory");
  27 return dest;
  28 }
  29 
  30 #define __HAVE_ARCH_STRNCPY
  31 extern inline char * strncpy(char * dest,const char *src,size_t count)
     /*  */
  32 {
  33 __asm__ __volatile__(
  34         "cld\n"
  35         "1:\tdecl %2\n\t"
  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         : /* no output */
  45         :"S" (src),"D" (dest),"c" (count):"si","di","ax","cx","memory");
  46 return dest;
  47 }
  48 
  49 #define __HAVE_ARCH_STRCAT
  50 extern inline char * strcat(char * dest,const char * src)
     /*  */
  51 {
  52 __asm__ __volatile__(
  53         "cld\n\t"
  54         "repne\n\t"
  55         "scasb\n\t"
  56         "decl %1\n"
  57         "1:\tlodsb\n\t"
  58         "stosb\n\t"
  59         "testb %%al,%%al\n\t"
  60         "jne 1b"
  61         : /* no output */
  62         :"S" (src),"D" (dest),"a" (0),"c" (0xffffffff):"si","di","ax","cx");
  63 return dest;
  64 }
  65 
  66 #define __HAVE_ARCH_STRNCAT
  67 extern inline char * strncat(char * dest,const char * src,size_t count)
     /*  */
  68 {
  69 __asm__ __volatile__(
  70         "cld\n\t"
  71         "repne\n\t"
  72         "scasb\n\t"
  73         "decl %1\n\t"
  74         "movl %4,%3\n"
  75         "1:\tdecl %3\n\t"
  76         "js 2f\n\t"
  77         "lodsb\n\t"
  78         "stosb\n\t"
  79         "testb %%al,%%al\n\t"
  80         "jne 1b\n"
  81         "2:\txorl %2,%2\n\t"
  82         "stosb"
  83         : /* no output */
  84         :"S" (src),"D" (dest),"a" (0),"c" (0xffffffff),"g" (count)
  85         :"si","di","ax","cx","memory");
  86 return dest;
  87 }
  88 
  89 #define __HAVE_ARCH_STRCMP
  90 extern inline int strcmp(const char * cs,const char * ct)
     /*  */
  91 {
  92 register int __res;
  93 __asm__ __volatile__(
  94         "cld\n"
  95         "1:\tlodsb\n\t"
  96         "scasb\n\t"
  97         "jne 2f\n\t"
  98         "testb %%al,%%al\n\t"
  99         "jne 1b\n\t"
 100         "xorl %%eax,%%eax\n\t"
 101         "jmp 3f\n"
 102         "2:\tsbbl %%eax,%%eax\n\t"
 103         "orb $1,%%eax\n"
 104         "3:"
 105         :"=a" (__res):"S" (cs),"D" (ct):"si","di");
 106 return __res;
 107 }
 108 
 109 #define __HAVE_ARCH_STRNCMP
 110 extern inline int strncmp(const char * cs,const char * ct,size_t count)
     /*  */
 111 {
 112 register int __res;
 113 __asm__ __volatile__(
 114         "cld\n"
 115         "1:\tdecl %3\n\t"
 116         "js 2f\n\t"
 117         "lodsb\n\t"
 118         "scasb\n\t"
 119         "jne 3f\n\t"
 120         "testb %%al,%%al\n\t"
 121         "jne 1b\n"
 122         "2:\txorl %%eax,%%eax\n\t"
 123         "jmp 4f\n"
 124         "3:\tsbbl %%eax,%%eax\n\t"
 125         "orb $1,%%al\n"
 126         "4:"
 127         :"=a" (__res):"S" (cs),"D" (ct),"c" (count):"si","di","cx");
 128 return __res;
 129 }
 130 
 131 #define __HAVE_ARCH_STRCHR
 132 extern inline char * strchr(const char * s, int c)
     /*  */
 133 {
 134 register char * __res;
 135 __asm__ __volatile__(
 136         "cld\n\t"
 137         "movb %%al,%%ah\n"
 138         "1:\tlodsb\n\t"
 139         "cmpb %%ah,%%al\n\t"
 140         "je 2f\n\t"
 141         "testb %%al,%%al\n\t"
 142         "jne 1b\n\t"
 143         "movl $1,%1\n"
 144         "2:\tmovl %1,%0\n\t"
 145         "decl %0"
 146         :"=a" (__res):"S" (s),"0" (c):"si");
 147 return __res;
 148 }
 149 
 150 #define __HAVE_ARCH_STRRCHR
 151 extern inline char * strrchr(const char * s, int c)
     /*  */
 152 {
 153 register char * __res;
 154 __asm__ __volatile__(
 155         "cld\n\t"
 156         "movb %%al,%%ah\n"
 157         "1:\tlodsb\n\t"
 158         "cmpb %%ah,%%al\n\t"
 159         "jne 2f\n\t"
 160         "leal -1(%%esi),%0\n"
 161         "2:\ttestb %%al,%%al\n\t"
 162         "jne 1b"
 163         :"=d" (__res):"0" (0),"S" (s),"a" (c):"ax","si");
 164 return __res;
 165 }
 166 
 167 #define __HAVE_ARCH_STRSPN
 168 extern inline size_t strspn(const char * cs, const char * ct)
     /*  */
 169 {
 170 register char * __res;
 171 __asm__ __volatile__(
 172         "cld\n\t"
 173         "movl %4,%%edi\n\t"
 174         "repne\n\t"
 175         "scasb\n\t"
 176         "notl %%ecx\n\t"
 177         "decl %%ecx\n\t"
 178         "movl %%ecx,%%edx\n"
 179         "1:\tlodsb\n\t"
 180         "testb %%al,%%al\n\t"
 181         "je 2f\n\t"
 182         "movl %4,%%edi\n\t"
 183         "movl %%edx,%%ecx\n\t"
 184         "repne\n\t"
 185         "scasb\n\t"
 186         "je 1b\n"
 187         "2:\tdecl %0"
 188         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 189         :"ax","cx","dx","di");
 190 return __res-cs;
 191 }
 192 
 193 #define __HAVE_ARCH_STRCSPN
 194 extern inline size_t strcspn(const char * cs, const char * ct)
     /*  */
 195 {
 196 register char * __res;
 197 __asm__ __volatile__(
 198         "cld\n\t"
 199         "movl %4,%%edi\n\t"
 200         "repne\n\t"
 201         "scasb\n\t"
 202         "notl %%ecx\n\t"
 203         "decl %%ecx\n\t"
 204         "movl %%ecx,%%edx\n"
 205         "1:\tlodsb\n\t"
 206         "testb %%al,%%al\n\t"
 207         "je 2f\n\t"
 208         "movl %4,%%edi\n\t"
 209         "movl %%edx,%%ecx\n\t"
 210         "repne\n\t"
 211         "scasb\n\t"
 212         "jne 1b\n"
 213         "2:\tdecl %0"
 214         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 215         :"ax","cx","dx","di");
 216 return __res-cs;
 217 }
 218 
 219 #define __HAVE_ARCH_STRPBRK
 220 extern inline char * strpbrk(const char * cs,const char * ct)
     /*  */
 221 {
 222 register char * __res;
 223 __asm__ __volatile__(
 224         "cld\n\t"
 225         "movl %4,%%edi\n\t"
 226         "repne\n\t"
 227         "scasb\n\t"
 228         "notl %%ecx\n\t"
 229         "decl %%ecx\n\t"
 230         "movl %%ecx,%%edx\n"
 231         "1:\tlodsb\n\t"
 232         "testb %%al,%%al\n\t"
 233         "je 2f\n\t"
 234         "movl %4,%%edi\n\t"
 235         "movl %%edx,%%ecx\n\t"
 236         "repne\n\t"
 237         "scasb\n\t"
 238         "jne 1b\n\t"
 239         "decl %0\n\t"
 240         "jmp 3f\n"
 241         "2:\txorl %0,%0\n"
 242         "3:"
 243         :"=S" (__res):"a" (0),"c" (0xffffffff),"0" (cs),"g" (ct)
 244         :"ax","cx","dx","di");
 245 return __res;
 246 }
 247 
 248 #define __HAVE_ARCH_STRSTR
 249 extern inline char * strstr(const char * cs,const char * ct)
     /*  */
 250 {
 251 register char * __res;
 252 __asm__ __volatile__(
 253         "cld\n\t" \
 254         "movl %4,%%edi\n\t"
 255         "repne\n\t"
 256         "scasb\n\t"
 257         "notl %%ecx\n\t"
 258         "decl %%ecx\n\t"        /* NOTE! This also sets Z if searchstring='' */
 259         "movl %%ecx,%%edx\n"
 260         "1:\tmovl %4,%%edi\n\t"
 261         "movl %%esi,%%eax\n\t"
 262         "movl %%edx,%%ecx\n\t"
 263         "repe\n\t"
 264         "cmpsb\n\t"
 265         "je 2f\n\t"             /* also works for empty string, see above */
 266         "xchgl %%eax,%%esi\n\t"
 267         "incl %%esi\n\t"
 268         "cmpb $0,-1(%%eax)\n\t"
 269         "jne 1b\n\t"
 270         "xorl %%eax,%%eax\n\t"
 271         "2:"
 272         :"=a" (__res):"0" (0),"c" (0xffffffff),"S" (cs),"g" (ct)
 273         :"cx","dx","di","si");
 274 return __res;
 275 }
 276 
 277 #define __HAVE_ARCH_STRLEN
 278 extern inline size_t strlen(const char * s)
     /*  */
 279 {
 280 register int __res;
 281 __asm__ __volatile__(
 282         "cld\n\t"
 283         "repne\n\t"
 284         "scasb\n\t"
 285         "notl %0\n\t"
 286         "decl %0"
 287         :"=c" (__res):"D" (s),"a" (0),"0" (0xffffffff):"di");
 288 return __res;
 289 }
 290 
 291 #define __HAVE_ARCH_STRTOK
 292 extern inline char * strtok(char * s,const char * ct)
     /*  */
 293 {
 294 register char * __res;
 295 __asm__ __volatile__(
 296         "testl %1,%1\n\t"
 297         "jne 1f\n\t"
 298         "testl %0,%0\n\t"
 299         "je 8f\n\t"
 300         "movl %0,%1\n"
 301         "1:\txorl %0,%0\n\t"
 302         "movl $-1,%%ecx\n\t"
 303         "xorl %%eax,%%eax\n\t"
 304         "cld\n\t"
 305         "movl %4,%%edi\n\t"
 306         "repne\n\t"
 307         "scasb\n\t"
 308         "notl %%ecx\n\t"
 309         "decl %%ecx\n\t"
 310         "je 7f\n\t"                     /* empty delimiter-string */
 311         "movl %%ecx,%%edx\n"
 312         "2:\tlodsb\n\t"
 313         "testb %%al,%%al\n\t"
 314         "je 7f\n\t"
 315         "movl %4,%%edi\n\t"
 316         "movl %%edx,%%ecx\n\t"
 317         "repne\n\t"
 318         "scasb\n\t"
 319         "je 2b\n\t"
 320         "decl %1\n\t"
 321         "cmpb $0,(%1)\n\t"
 322         "je 7f\n\t"
 323         "movl %1,%0\n"
 324         "3:\tlodsb\n\t"
 325         "testb %%al,%%al\n\t"
 326         "je 5f\n\t"
 327         "movl %4,%%edi\n\t"
 328         "movl %%edx,%%ecx\n\t"
 329         "repne\n\t"
 330         "scasb\n\t"
 331         "jne 3b\n\t"
 332         "decl %1\n\t"
 333         "cmpb $0,(%1)\n\t"
 334         "je 5f\n\t"
 335         "movb $0,(%1)\n\t"
 336         "incl %1\n\t"
 337         "jmp 6f\n"
 338         "5:\txorl %1,%1\n"
 339         "6:\tcmpb $0,(%0)\n\t"
 340         "jne 7f\n\t"
 341         "xorl %0,%0\n"
 342         "7:\ttestl %0,%0\n\t"
 343         "jne 8f\n\t"
 344         "movl %0,%1\n"
 345         "8:"
 346         :"=b" (__res),"=S" (___strtok)
 347         :"0" (___strtok),"1" (s),"g" (ct)
 348         :"ax","cx","dx","di","memory");
 349 return __res;
 350 }
 351 
 352 extern inline void * __memcpy(void * to, const void * from, size_t n)
     /*  */
 353 {
 354 __asm__ __volatile__(
 355         "cld\n\t"
 356         "rep ; movsl\n\t"
 357         "testb $2,%b1\n\t"
 358         "je 1f\n\t"
 359         "movsw\n"
 360         "1:\ttestb $1,%b1\n\t"
 361         "je 2f\n\t"
 362         "movsb\n"
 363         "2:"
 364         : /* no output */
 365         :"c" (n/4), "q" (n),"D" ((long) to),"S" ((long) from)
 366         : "cx","di","si","memory");
 367 return (to);
 368 }
 369 
 370 /*
 371  * This looks horribly ugly, but the compiler can optimize it totally,
 372  * as the count is constant.
 373  */
 374 extern inline void * __constant_memcpy(void * to, const void * from, size_t n)
     /*  */
 375 {
 376         switch (n) {
 377                 case 0:
 378                         return to;
 379                 case 1:
 380                         *(unsigned char *)to = *(const unsigned char *)from;
 381                         return to;
 382                 case 2:
 383                         *(unsigned short *)to = *(const unsigned short *)from;
 384                         return to;
 385                 case 3:
 386                         *(unsigned short *)to = *(const unsigned short *)from;
 387                         *(2+(unsigned char *)to) = *(2+(const unsigned char *)from);
 388                         return to;
 389                 case 4:
 390                         *(unsigned long *)to = *(const unsigned long *)from;
 391                         return to;
 392         }
 393 #define COMMON(x) \
 394 __asm__("cld\n\t" \
 395         "rep ; movsl" \
 396         x \
 397         : /* no outputs */ \
 398         : "c" (n/4),"D" ((long) to),"S" ((long) from) \
 399         : "cx","di","si","memory");
 400 
 401         switch (n % 4) {
 402                 case 0: COMMON(""); return to;
 403                 case 1: COMMON("\n\tmovsb"); return to;
 404                 case 2: COMMON("\n\tmovsw"); return to;
 405                 case 3: COMMON("\n\tmovsw\n\tmovsb"); return to;
 406         }
 407 #undef COMMON
 408 }
 409 
 410 #define __HAVE_ARCH_MEMCPY
 411 #define memcpy(t, f, n) \
 412 (__builtin_constant_p(n) ? \
 413  __constant_memcpy((t),(f),(n)) : \
 414  __memcpy((t),(f),(n)))
 415 
 416 #define __HAVE_ARCH_MEMMOVE
 417 extern inline void * memmove(void * dest,const void * src, size_t n)
     /*  */
 418 {
 419 if (dest<src)
 420 __asm__ __volatile__(
 421         "cld\n\t"
 422         "rep\n\t"
 423         "movsb"
 424         : /* no output */
 425         :"c" (n),"S" (src),"D" (dest)
 426         :"cx","si","di");
 427 else
 428 __asm__ __volatile__(
 429         "std\n\t"
 430         "rep\n\t"
 431         "movsb\n\t"
 432         "cld"
 433         : /* no output */
 434         :"c" (n),
 435          "S" (n-1+(const char *)src),
 436          "D" (n-1+(char *)dest)
 437         :"cx","si","di","memory");
 438 return dest;
 439 }
 440 
 441 #define memcmp __builtin_memcmp
 442 
 443 #define __HAVE_ARCH_MEMCHR
 444 extern inline void * memchr(const void * cs,int c,size_t count)
     /*  */
 445 {
 446 register void * __res;
 447 if (!count)
 448         return NULL;
 449 __asm__ __volatile__(
 450         "cld\n\t"
 451         "repne\n\t"
 452         "scasb\n\t"
 453         "je 1f\n\t"
 454         "movl $1,%0\n"
 455         "1:\tdecl %0"
 456         :"=D" (__res):"a" (c),"D" (cs),"c" (count)
 457         :"cx");
 458 return __res;
 459 }
 460 
 461 extern inline void * __memset_generic(void * s, char c,size_t count)
     /*  */
 462 {
 463 __asm__ __volatile__(
 464         "cld\n\t"
 465         "rep\n\t"
 466         "stosb"
 467         : /* no output */
 468         :"a" (c),"D" (s),"c" (count)
 469         :"cx","di","memory");
 470 return s;
 471 }
 472 
 473 /* we might want to write optimized versions of these later */
 474 #define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))
 475 
 476 /*
 477  * memset(x,0,y) is a reasonably common thing to do, so we want to fill
 478  * things 32 bits at a time even when we don't know the size of the
 479  * area at compile-time..
 480  */
 481 extern inline void * __constant_c_memset(void * s, unsigned long c, size_t count)
     /*  */
 482 {
 483 __asm__ __volatile__(
 484         "cld\n\t"
 485         "rep ; stosl\n\t"
 486         "testb $2,%b1\n\t"
 487         "je 1f\n\t"
 488         "stosw\n"
 489         "1:\ttestb $1,%b1\n\t"
 490         "je 2f\n\t"
 491         "stosb\n"
 492         "2:"
 493         : /* no output */
 494         :"a" (c), "q" (count), "c" (count/4), "D" ((long) s)
 495         :"cx","di","memory");
 496 return (s);     
 497 }
 498 
 499 /* Added by Gertjan van Wingerde to make minix and sysv module work */
 500 #define __HAVE_ARCH_STRNLEN
 501 extern inline size_t strnlen(const char * s, size_t count)
     /*  */
 502 {
 503 register int __res;
 504 __asm__ __volatile__(
 505         "movl %1,%0\n\t"
 506         "jmp 2f\n"
 507         "1:\tcmpb $0,(%0)\n\t"
 508         "je 3f\n\t"
 509         "incl %0\n"
 510         "2:\tdecl %2\n\t"
 511         "cmpl $-1,%2\n\t"
 512         "jne 1b\n"
 513         "3:\tsubl %1,%0"
 514         :"=a" (__res):"c" (s),"d" (count));
 515 return __res;
 516 }
 517 /* end of additional stuff */
 518 
 519 /*
 520  * This looks horribly ugly, but the compiler can optimize it totally,
 521  * as we by now know that both pattern and count is constant..
 522  */
 523 extern inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
     /*  */
 524 {
 525         switch (count) {
 526                 case 0:
 527                         return s;
 528                 case 1:
 529                         *(unsigned char *)s = pattern;
 530                         return s;
 531                 case 2:
 532                         *(unsigned short *)s = pattern;
 533                         return s;
 534                 case 3:
 535                         *(unsigned short *)s = pattern;
 536                         *(2+(unsigned char *)s) = pattern;
 537                         return s;
 538                 case 4:
 539                         *(unsigned long *)s = pattern;
 540                         return s;
 541         }
 542 #define COMMON(x) \
 543 __asm__("cld\n\t" \
 544         "rep ; stosl" \
 545         x \
 546         : /* no outputs */ \
 547         : "a" (pattern),"c" (count/4),"D" ((long) s) \
 548         : "cx","di","memory")
 549 
 550         switch (count % 4) {
 551                 case 0: COMMON(""); return s;
 552                 case 1: COMMON("\n\tstosb"); return s;
 553                 case 2: COMMON("\n\tstosw"); return s;
 554                 case 3: COMMON("\n\tstosw\n\tstosb"); return s;
 555         }
 556 #undef COMMON
 557 }
 558 
 559 #define __constant_c_x_memset(s, c, count) \
 560 (__builtin_constant_p(count) ? \
 561  __constant_c_and_count_memset((s),(c),(count)) : \
 562  __constant_c_memset((s),(c),(count)))
 563 
 564 #define __memset(s, c, count) \
 565 (__builtin_constant_p(count) ? \
 566  __constant_count_memset((s),(c),(count)) : \
 567  __memset_generic((s),(c),(count)))
 568 
 569 #define __HAVE_ARCH_MEMSET
 570 #define memset(s, c, count) \
 571 (__builtin_constant_p(c) ? \
 572  __constant_c_x_memset((s),(0x01010101UL*(unsigned char)c),(count)) : \
 573  __memset((s),(c),(count)))
 574 
 575 /*
 576  * find the first occurrence of byte 'c', or 1 past the area if none
 577  */
 578 #define __HAVE_ARCH_MEMSCAN
 579 extern inline void * memscan(void * addr, int c, size_t size)
     /*  */
 580 {
 581         if (!size)
 582                 return addr;
 583         __asm__("cld
 584                 repnz; scasb
 585                 jnz 1f
 586                 dec %%edi
 587 1:              "
 588                 : "=D" (addr), "=c" (size)
 589                 : "0" (addr), "1" (size), "a" (c));
 590         return addr;
 591 }
 592 
 593 #endif
/* */
root/include/asm-i386/string.h

INCLUDED FROM

DEFINITIONS
