xref: /linux/arch/x86/include/asm/string_32.h (revision 5bdef865eb358b6f3760e25e591ae115e9eeddef)
1 #ifndef _ASM_X86_STRING_32_H
2 #define _ASM_X86_STRING_32_H
3 
4 #ifdef __KERNEL__
5 
6 /* Let gcc decide whether to inline or use the out of line functions */
7 
8 #define __HAVE_ARCH_STRCPY
9 extern char *strcpy(char *dest, const char *src);
10 
11 #define __HAVE_ARCH_STRNCPY
12 extern char *strncpy(char *dest, const char *src, size_t count);
13 
14 #define __HAVE_ARCH_STRCAT
15 extern char *strcat(char *dest, const char *src);
16 
17 #define __HAVE_ARCH_STRNCAT
18 extern char *strncat(char *dest, const char *src, size_t count);
19 
20 #define __HAVE_ARCH_STRCMP
21 extern int strcmp(const char *cs, const char *ct);
22 
23 #define __HAVE_ARCH_STRNCMP
24 extern int strncmp(const char *cs, const char *ct, size_t count);
25 
26 #define __HAVE_ARCH_STRCHR
27 extern char *strchr(const char *s, int c);
28 
29 #define __HAVE_ARCH_STRLEN
30 extern size_t strlen(const char *s);
31 
32 static __always_inline void *__memcpy(void *to, const void *from, size_t n)
33 {
34 	int d0, d1, d2;
35 	asm volatile("rep ; movsl\n\t"
36 		     "movl %4,%%ecx\n\t"
37 		     "andl $3,%%ecx\n\t"
38 		     "jz 1f\n\t"
39 		     "rep ; movsb\n\t"
40 		     "1:"
41 		     : "=&c" (d0), "=&D" (d1), "=&S" (d2)
42 		     : "0" (n / 4), "g" (n), "1" ((long)to), "2" ((long)from)
43 		     : "memory");
44 	return to;
45 }
46 
47 /*
48  * This looks ugly, but the compiler can optimize it totally,
49  * as the count is constant.
50  */
51 static __always_inline void *__constant_memcpy(void *to, const void *from,
52 					       size_t n)
53 {
54 	long esi, edi;
55 	if (!n)
56 		return to;
57 
58 	switch (n) {
59 	case 1:
60 		*(char *)to = *(char *)from;
61 		return to;
62 	case 2:
63 		*(short *)to = *(short *)from;
64 		return to;
65 	case 4:
66 		*(int *)to = *(int *)from;
67 		return to;
68 
69 	case 3:
70 		*(short *)to = *(short *)from;
71 		*((char *)to + 2) = *((char *)from + 2);
72 		return to;
73 	case 5:
74 		*(int *)to = *(int *)from;
75 		*((char *)to + 4) = *((char *)from + 4);
76 		return to;
77 	case 6:
78 		*(int *)to = *(int *)from;
79 		*((short *)to + 2) = *((short *)from + 2);
80 		return to;
81 	case 8:
82 		*(int *)to = *(int *)from;
83 		*((int *)to + 1) = *((int *)from + 1);
84 		return to;
85 	}
86 
87 	esi = (long)from;
88 	edi = (long)to;
89 	if (n >= 5 * 4) {
90 		/* large block: use rep prefix */
91 		int ecx;
92 		asm volatile("rep ; movsl"
93 			     : "=&c" (ecx), "=&D" (edi), "=&S" (esi)
94 			     : "0" (n / 4), "1" (edi), "2" (esi)
95 			     : "memory"
96 		);
97 	} else {
98 		/* small block: don't clobber ecx + smaller code */
99 		if (n >= 4 * 4)
100 			asm volatile("movsl"
101 				     : "=&D"(edi), "=&S"(esi)
102 				     : "0"(edi), "1"(esi)
103 				     : "memory");
104 		if (n >= 3 * 4)
105 			asm volatile("movsl"
106 				     : "=&D"(edi), "=&S"(esi)
107 				     : "0"(edi), "1"(esi)
108 				     : "memory");
109 		if (n >= 2 * 4)
110 			asm volatile("movsl"
111 				     : "=&D"(edi), "=&S"(esi)
112 				     : "0"(edi), "1"(esi)
113 				     : "memory");
114 		if (n >= 1 * 4)
115 			asm volatile("movsl"
116 				     : "=&D"(edi), "=&S"(esi)
117 				     : "0"(edi), "1"(esi)
118 				     : "memory");
119 	}
120 	switch (n % 4) {
121 		/* tail */
122 	case 0:
123 		return to;
124 	case 1:
125 		asm volatile("movsb"
126 			     : "=&D"(edi), "=&S"(esi)
127 			     : "0"(edi), "1"(esi)
128 			     : "memory");
129 		return to;
130 	case 2:
131 		asm volatile("movsw"
132 			     : "=&D"(edi), "=&S"(esi)
133 			     : "0"(edi), "1"(esi)
134 			     : "memory");
135 		return to;
136 	default:
137 		asm volatile("movsw\n\tmovsb"
138 			     : "=&D"(edi), "=&S"(esi)
139 			     : "0"(edi), "1"(esi)
140 			     : "memory");
141 		return to;
142 	}
143 }
144 
145 #define __HAVE_ARCH_MEMCPY
146 
147 #ifdef CONFIG_X86_USE_3DNOW
148 
149 #include <asm/mmx.h>
150 
151 /*
152  *	This CPU favours 3DNow strongly (eg AMD Athlon)
153  */
154 
155 static inline void *__constant_memcpy3d(void *to, const void *from, size_t len)
156 {
157 	if (len < 512)
158 		return __constant_memcpy(to, from, len);
159 	return _mmx_memcpy(to, from, len);
160 }
161 
162 static inline void *__memcpy3d(void *to, const void *from, size_t len)
163 {
164 	if (len < 512)
165 		return __memcpy(to, from, len);
166 	return _mmx_memcpy(to, from, len);
167 }
168 
169 #define memcpy(t, f, n)				\
170 	(__builtin_constant_p((n))		\
171 	 ? __constant_memcpy3d((t), (f), (n))	\
172 	 : __memcpy3d((t), (f), (n)))
173 
174 #else
175 
176 /*
177  *	No 3D Now!
178  */
179 
180 #ifndef CONFIG_KMEMCHECK
181 #define memcpy(t, f, n)				\
182 	(__builtin_constant_p((n))		\
183 	 ? __constant_memcpy((t), (f), (n))	\
184 	 : __memcpy((t), (f), (n)))
185 #else
186 /*
187  * kmemcheck becomes very happy if we use the REP instructions unconditionally,
188  * because it means that we know both memory operands in advance.
189  */
190 #define memcpy(t, f, n) __memcpy((t), (f), (n))
191 #endif
192 
193 #endif
194 
195 #define __HAVE_ARCH_MEMMOVE
196 void *memmove(void *dest, const void *src, size_t n);
197 
198 #define memcmp __builtin_memcmp
199 
200 #define __HAVE_ARCH_MEMCHR
201 extern void *memchr(const void *cs, int c, size_t count);
202 
203 static inline void *__memset_generic(void *s, char c, size_t count)
204 {
205 	int d0, d1;
206 	asm volatile("rep\n\t"
207 		     "stosb"
208 		     : "=&c" (d0), "=&D" (d1)
209 		     : "a" (c), "1" (s), "0" (count)
210 		     : "memory");
211 	return s;
212 }
213 
214 /* we might want to write optimized versions of these later */
215 #define __constant_count_memset(s, c, count) __memset_generic((s), (c), (count))
216 
217 /*
218  * memset(x, 0, y) is a reasonably common thing to do, so we want to fill
219  * things 32 bits at a time even when we don't know the size of the
220  * area at compile-time..
221  */
222 static __always_inline
223 void *__constant_c_memset(void *s, unsigned long c, size_t count)
224 {
225 	int d0, d1;
226 	asm volatile("rep ; stosl\n\t"
227 		     "testb $2,%b3\n\t"
228 		     "je 1f\n\t"
229 		     "stosw\n"
230 		     "1:\ttestb $1,%b3\n\t"
231 		     "je 2f\n\t"
232 		     "stosb\n"
233 		     "2:"
234 		     : "=&c" (d0), "=&D" (d1)
235 		     : "a" (c), "q" (count), "0" (count/4), "1" ((long)s)
236 		     : "memory");
237 	return s;
238 }
239 
240 /* Added by Gertjan van Wingerde to make minix and sysv module work */
241 #define __HAVE_ARCH_STRNLEN
242 extern size_t strnlen(const char *s, size_t count);
243 /* end of additional stuff */
244 
245 #define __HAVE_ARCH_STRSTR
246 extern char *strstr(const char *cs, const char *ct);
247 
248 /*
249  * This looks horribly ugly, but the compiler can optimize it totally,
250  * as we by now know that both pattern and count is constant..
251  */
252 static __always_inline
253 void *__constant_c_and_count_memset(void *s, unsigned long pattern,
254 				    size_t count)
255 {
256 	switch (count) {
257 	case 0:
258 		return s;
259 	case 1:
260 		*(unsigned char *)s = pattern & 0xff;
261 		return s;
262 	case 2:
263 		*(unsigned short *)s = pattern & 0xffff;
264 		return s;
265 	case 3:
266 		*(unsigned short *)s = pattern & 0xffff;
267 		*((unsigned char *)s + 2) = pattern & 0xff;
268 		return s;
269 	case 4:
270 		*(unsigned long *)s = pattern;
271 		return s;
272 	}
273 
274 #define COMMON(x)							\
275 	asm volatile("rep ; stosl"					\
276 		     x							\
277 		     : "=&c" (d0), "=&D" (d1)				\
278 		     : "a" (eax), "0" (count/4), "1" ((long)s)	\
279 		     : "memory")
280 
281 	{
282 		int d0, d1;
283 #if __GNUC__ == 4 && __GNUC_MINOR__ == 0
284 		/* Workaround for broken gcc 4.0 */
285 		register unsigned long eax asm("%eax") = pattern;
286 #else
287 		unsigned long eax = pattern;
288 #endif
289 
290 		switch (count % 4) {
291 		case 0:
292 			COMMON("");
293 			return s;
294 		case 1:
295 			COMMON("\n\tstosb");
296 			return s;
297 		case 2:
298 			COMMON("\n\tstosw");
299 			return s;
300 		default:
301 			COMMON("\n\tstosw\n\tstosb");
302 			return s;
303 		}
304 	}
305 
306 #undef COMMON
307 }
308 
309 #define __constant_c_x_memset(s, c, count)			\
310 	(__builtin_constant_p(count)				\
311 	 ? __constant_c_and_count_memset((s), (c), (count))	\
312 	 : __constant_c_memset((s), (c), (count)))
313 
314 #define __memset(s, c, count)				\
315 	(__builtin_constant_p(count)			\
316 	 ? __constant_count_memset((s), (c), (count))	\
317 	 : __memset_generic((s), (c), (count)))
318 
319 #define __HAVE_ARCH_MEMSET
320 #define memset(s, c, count)						\
321 	(__builtin_constant_p(c)					\
322 	 ? __constant_c_x_memset((s), (0x01010101UL * (unsigned char)(c)), \
323 				 (count))				\
324 	 : __memset((s), (c), (count)))
325 
326 /*
327  * find the first occurrence of byte 'c', or 1 past the area if none
328  */
329 #define __HAVE_ARCH_MEMSCAN
330 extern void *memscan(void *addr, int c, size_t size);
331 
332 #endif /* __KERNEL__ */
333 
334 #endif /* _ASM_X86_STRING_32_H */
335