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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _I386_STRING_H_
2#define _I386_STRING_H_
3
4#ifdef __KERNEL__
5#include <linux/config.h>
6/*
7 * On a 486 or Pentium, we are better off not using the
8 * byte string operations. But on a 386 or a PPro the
9 * byte string ops are faster than doing it by hand
10 * (MUCH faster on a Pentium).
11 */
12
13/*
14 * This string-include defines all string functions as inline
15 * functions. Use gcc. It also assumes ds=es=data space, this should be
16 * normal. Most of the string-functions are rather heavily hand-optimized,
17 * see especially strsep,strstr,str[c]spn. They should work, but are not
18 * very easy to understand. Everything is done entirely within the register
19 * set, making the functions fast and clean. String instructions have been
20 * used through-out, making for "slightly" unclear code :-)
21 *
22 * NO Copyright (C) 1991, 1992 Linus Torvalds,
23 * consider these trivial functions to be PD.
24 */
25
26/* AK: in fact I bet it would be better to move this stuff all out of line.
27 */
28
29#define __HAVE_ARCH_STRCPY
30static inline char * strcpy(char * dest,const char *src)
31{
32int d0, d1, d2;
33__asm__ __volatile__(
34 "1:\tlodsb\n\t"
35 "stosb\n\t"
36 "testb %%al,%%al\n\t"
37 "jne 1b"
38 : "=&S" (d0), "=&D" (d1), "=&a" (d2)
39 :"0" (src),"1" (dest) : "memory");
40return dest;
41}
42
43#define __HAVE_ARCH_STRNCPY
44static inline char * strncpy(char * dest,const char *src,size_t count)
45{
46int d0, d1, d2, d3;
47__asm__ __volatile__(
48 "1:\tdecl %2\n\t"
49 "js 2f\n\t"
50 "lodsb\n\t"
51 "stosb\n\t"
52 "testb %%al,%%al\n\t"
53 "jne 1b\n\t"
54 "rep\n\t"
55 "stosb\n"
56 "2:"
57 : "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
58 :"0" (src),"1" (dest),"2" (count) : "memory");
59return dest;
60}
61
62#define __HAVE_ARCH_STRCAT
63static inline char * strcat(char * dest,const char * src)
64{
65int d0, d1, d2, d3;
66__asm__ __volatile__(
67 "repne\n\t"
68 "scasb\n\t"
69 "decl %1\n"
70 "1:\tlodsb\n\t"
71 "stosb\n\t"
72 "testb %%al,%%al\n\t"
73 "jne 1b"
74 : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
75 : "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu):"memory");
76return dest;
77}
78
79#define __HAVE_ARCH_STRNCAT
80static inline char * strncat(char * dest,const char * src,size_t count)
81{
82int d0, d1, d2, d3;
83__asm__ __volatile__(
84 "repne\n\t"
85 "scasb\n\t"
86 "decl %1\n\t"
87 "movl %8,%3\n"
88 "1:\tdecl %3\n\t"
89 "js 2f\n\t"
90 "lodsb\n\t"
91 "stosb\n\t"
92 "testb %%al,%%al\n\t"
93 "jne 1b\n"
94 "2:\txorl %2,%2\n\t"
95 "stosb"
96 : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
97 : "0" (src),"1" (dest),"2" (0),"3" (0xffffffffu), "g" (count)
98 : "memory");
99return dest;
100}
101
102#define __HAVE_ARCH_STRCMP
103static inline int strcmp(const char * cs,const char * ct)
104{
105int d0, d1;
106register int __res;
107__asm__ __volatile__(
108 "1:\tlodsb\n\t"
109 "scasb\n\t"
110 "jne 2f\n\t"
111 "testb %%al,%%al\n\t"
112 "jne 1b\n\t"
113 "xorl %%eax,%%eax\n\t"
114 "jmp 3f\n"
115 "2:\tsbbl %%eax,%%eax\n\t"
116 "orb $1,%%al\n"
117 "3:"
118 :"=a" (__res), "=&S" (d0), "=&D" (d1)
119 :"1" (cs),"2" (ct));
120return __res;
121}
122
123#define __HAVE_ARCH_STRNCMP
124static inline int strncmp(const char * cs,const char * ct,size_t count)
125{
126register int __res;
127int d0, d1, d2;
128__asm__ __volatile__(
129 "1:\tdecl %3\n\t"
130 "js 2f\n\t"
131 "lodsb\n\t"
132 "scasb\n\t"
133 "jne 3f\n\t"
134 "testb %%al,%%al\n\t"
135 "jne 1b\n"
136 "2:\txorl %%eax,%%eax\n\t"
137 "jmp 4f\n"
138 "3:\tsbbl %%eax,%%eax\n\t"
139 "orb $1,%%al\n"
140 "4:"
141 :"=a" (__res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
142 :"1" (cs),"2" (ct),"3" (count));
143return __res;
144}
145
146#define __HAVE_ARCH_STRCHR
147static inline char * strchr(const char * s, int c)
148{
149int d0;
150register char * __res;
151__asm__ __volatile__(
152 "movb %%al,%%ah\n"
153 "1:\tlodsb\n\t"
154 "cmpb %%ah,%%al\n\t"
155 "je 2f\n\t"
156 "testb %%al,%%al\n\t"
157 "jne 1b\n\t"
158 "movl $1,%1\n"
159 "2:\tmovl %1,%0\n\t"
160 "decl %0"
161 :"=a" (__res), "=&S" (d0) : "1" (s),"0" (c));
162return __res;
163}
164
165#define __HAVE_ARCH_STRRCHR
166static inline char * strrchr(const char * s, int c)
167{
168int d0, d1;
169register char * __res;
170__asm__ __volatile__(
171 "movb %%al,%%ah\n"
172 "1:\tlodsb\n\t"
173 "cmpb %%ah,%%al\n\t"
174 "jne 2f\n\t"
175 "leal -1(%%esi),%0\n"
176 "2:\ttestb %%al,%%al\n\t"
177 "jne 1b"
178 :"=g" (__res), "=&S" (d0), "=&a" (d1) :"0" (0),"1" (s),"2" (c));
179return __res;
180}
181
182#define __HAVE_ARCH_STRLEN
183static inline size_t strlen(const char * s)
184{
185int d0;
186register int __res;
187__asm__ __volatile__(
188 "repne\n\t"
189 "scasb\n\t"
190 "notl %0\n\t"
191 "decl %0"
192 :"=c" (__res), "=&D" (d0) :"1" (s),"a" (0), "0" (0xffffffffu));
193return __res;
194}
195
196static inline void * __memcpy(void * to, const void * from, size_t n)
197{
198int d0, d1, d2;
199__asm__ __volatile__(
200 "rep ; movsl\n\t"
Denis Vlasenkod5b63d72005-05-01 08:58:48 -0700201 "movl %4,%%ecx\n\t"
202 "andl $3,%%ecx\n\t"
203#if 1 /* want to pay 2 byte penalty for a chance to skip microcoded rep? */
204 "jz 1f\n\t"
205#endif
206 "rep ; movsb\n\t"
207 "1:"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 : "=&c" (d0), "=&D" (d1), "=&S" (d2)
Denis Vlasenkod5b63d72005-05-01 08:58:48 -0700209 : "0" (n/4), "g" (n), "1" ((long) to), "2" ((long) from)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210 : "memory");
211return (to);
212}
213
214/*
Denis Vlasenkod5b63d72005-05-01 08:58:48 -0700215 * This looks ugly, but the compiler can optimize it totally,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 * as the count is constant.
217 */
218static inline void * __constant_memcpy(void * to, const void * from, size_t n)
219{
Denis Vlasenkod5b63d72005-05-01 08:58:48 -0700220 long esi, edi;
221 if (!n) return to;
222#if 1 /* want to do small copies with non-string ops? */
223 switch (n) {
224 case 1: *(char*)to = *(char*)from; return to;
225 case 2: *(short*)to = *(short*)from; return to;
226 case 4: *(int*)to = *(int*)from; return to;
227#if 1 /* including those doable with two moves? */
228 case 3: *(short*)to = *(short*)from;
229 *((char*)to+2) = *((char*)from+2); return to;
230 case 5: *(int*)to = *(int*)from;
231 *((char*)to+4) = *((char*)from+4); return to;
232 case 6: *(int*)to = *(int*)from;
233 *((short*)to+2) = *((short*)from+2); return to;
234 case 8: *(int*)to = *(int*)from;
235 *((int*)to+1) = *((int*)from+1); return to;
236#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 }
Denis Vlasenkod5b63d72005-05-01 08:58:48 -0700238#endif
239 esi = (long) from;
240 edi = (long) to;
241 if (n >= 5*4) {
242 /* large block: use rep prefix */
243 int ecx;
244 __asm__ __volatile__(
245 "rep ; movsl"
246 : "=&c" (ecx), "=&D" (edi), "=&S" (esi)
247 : "0" (n/4), "1" (edi),"2" (esi)
248 : "memory"
249 );
250 } else {
251 /* small block: don't clobber ecx + smaller code */
252 if (n >= 4*4) __asm__ __volatile__("movsl"
253 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
254 if (n >= 3*4) __asm__ __volatile__("movsl"
255 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
256 if (n >= 2*4) __asm__ __volatile__("movsl"
257 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
258 if (n >= 1*4) __asm__ __volatile__("movsl"
259 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
260 }
261 switch (n % 4) {
262 /* tail */
263 case 0: return to;
264 case 1: __asm__ __volatile__("movsb"
265 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
266 return to;
267 case 2: __asm__ __volatile__("movsw"
268 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
269 return to;
270 default: __asm__ __volatile__("movsw\n\tmovsb"
271 :"=&D"(edi),"=&S"(esi):"0"(edi),"1"(esi):"memory");
272 return to;
273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274}
275
276#define __HAVE_ARCH_MEMCPY
277
278#ifdef CONFIG_X86_USE_3DNOW
279
280#include <asm/mmx.h>
281
282/*
283 * This CPU favours 3DNow strongly (eg AMD Athlon)
284 */
285
286static inline void * __constant_memcpy3d(void * to, const void * from, size_t len)
287{
288 if (len < 512)
289 return __constant_memcpy(to, from, len);
290 return _mmx_memcpy(to, from, len);
291}
292
293static __inline__ void *__memcpy3d(void *to, const void *from, size_t len)
294{
295 if (len < 512)
296 return __memcpy(to, from, len);
297 return _mmx_memcpy(to, from, len);
298}
299
300#define memcpy(t, f, n) \
301(__builtin_constant_p(n) ? \
302 __constant_memcpy3d((t),(f),(n)) : \
303 __memcpy3d((t),(f),(n)))
304
305#else
306
307/*
308 * No 3D Now!
309 */
310
311#define memcpy(t, f, n) \
312(__builtin_constant_p(n) ? \
313 __constant_memcpy((t),(f),(n)) : \
314 __memcpy((t),(f),(n)))
315
316#endif
317
318#define __HAVE_ARCH_MEMMOVE
319void *memmove(void * dest,const void * src, size_t n);
320
321#define memcmp __builtin_memcmp
322
323#define __HAVE_ARCH_MEMCHR
324static inline void * memchr(const void * cs,int c,size_t count)
325{
326int d0;
327register void * __res;
328if (!count)
329 return NULL;
330__asm__ __volatile__(
331 "repne\n\t"
332 "scasb\n\t"
333 "je 1f\n\t"
334 "movl $1,%0\n"
335 "1:\tdecl %0"
336 :"=D" (__res), "=&c" (d0) : "a" (c),"0" (cs),"1" (count));
337return __res;
338}
339
340static inline void * __memset_generic(void * s, char c,size_t count)
341{
342int d0, d1;
343__asm__ __volatile__(
344 "rep\n\t"
345 "stosb"
346 : "=&c" (d0), "=&D" (d1)
347 :"a" (c),"1" (s),"0" (count)
348 :"memory");
349return s;
350}
351
352/* we might want to write optimized versions of these later */
353#define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))
354
355/*
356 * memset(x,0,y) is a reasonably common thing to do, so we want to fill
357 * things 32 bits at a time even when we don't know the size of the
358 * area at compile-time..
359 */
360static inline void * __constant_c_memset(void * s, unsigned long c, size_t count)
361{
362int d0, d1;
363__asm__ __volatile__(
364 "rep ; stosl\n\t"
365 "testb $2,%b3\n\t"
366 "je 1f\n\t"
367 "stosw\n"
368 "1:\ttestb $1,%b3\n\t"
369 "je 2f\n\t"
370 "stosb\n"
371 "2:"
372 : "=&c" (d0), "=&D" (d1)
373 :"a" (c), "q" (count), "0" (count/4), "1" ((long) s)
374 :"memory");
375return (s);
376}
377
378/* Added by Gertjan van Wingerde to make minix and sysv module work */
379#define __HAVE_ARCH_STRNLEN
380static inline size_t strnlen(const char * s, size_t count)
381{
382int d0;
383register int __res;
384__asm__ __volatile__(
385 "movl %2,%0\n\t"
386 "jmp 2f\n"
387 "1:\tcmpb $0,(%0)\n\t"
388 "je 3f\n\t"
389 "incl %0\n"
390 "2:\tdecl %1\n\t"
391 "cmpl $-1,%1\n\t"
392 "jne 1b\n"
393 "3:\tsubl %2,%0"
394 :"=a" (__res), "=&d" (d0)
395 :"c" (s),"1" (count));
396return __res;
397}
398/* end of additional stuff */
399
400#define __HAVE_ARCH_STRSTR
401
402extern char *strstr(const char *cs, const char *ct);
403
404/*
405 * This looks horribly ugly, but the compiler can optimize it totally,
406 * as we by now know that both pattern and count is constant..
407 */
408static inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
409{
410 switch (count) {
411 case 0:
412 return s;
413 case 1:
414 *(unsigned char *)s = pattern;
415 return s;
416 case 2:
417 *(unsigned short *)s = pattern;
418 return s;
419 case 3:
420 *(unsigned short *)s = pattern;
421 *(2+(unsigned char *)s) = pattern;
422 return s;
423 case 4:
424 *(unsigned long *)s = pattern;
425 return s;
426 }
427#define COMMON(x) \
428__asm__ __volatile__( \
429 "rep ; stosl" \
430 x \
431 : "=&c" (d0), "=&D" (d1) \
432 : "a" (pattern),"0" (count/4),"1" ((long) s) \
433 : "memory")
434{
435 int d0, d1;
436 switch (count % 4) {
437 case 0: COMMON(""); return s;
438 case 1: COMMON("\n\tstosb"); return s;
439 case 2: COMMON("\n\tstosw"); return s;
440 default: COMMON("\n\tstosw\n\tstosb"); return s;
441 }
442}
443
444#undef COMMON
445}
446
447#define __constant_c_x_memset(s, c, count) \
448(__builtin_constant_p(count) ? \
449 __constant_c_and_count_memset((s),(c),(count)) : \
450 __constant_c_memset((s),(c),(count)))
451
452#define __memset(s, c, count) \
453(__builtin_constant_p(count) ? \
454 __constant_count_memset((s),(c),(count)) : \
455 __memset_generic((s),(c),(count)))
456
457#define __HAVE_ARCH_MEMSET
458#define memset(s, c, count) \
459(__builtin_constant_p(c) ? \
460 __constant_c_x_memset((s),(0x01010101UL*(unsigned char)(c)),(count)) : \
461 __memset((s),(c),(count)))
462
463/*
464 * find the first occurrence of byte 'c', or 1 past the area if none
465 */
466#define __HAVE_ARCH_MEMSCAN
467static inline void * memscan(void * addr, int c, size_t size)
468{
469 if (!size)
470 return addr;
471 __asm__("repnz; scasb\n\t"
472 "jnz 1f\n\t"
473 "dec %%edi\n"
474 "1:"
475 : "=D" (addr), "=c" (size)
476 : "0" (addr), "1" (size), "a" (c));
477 return addr;
478}
479
480#endif /* __KERNEL__ */
481
482#endif