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1/*
2 * Optimized string functions
3 *
4 * S390 version
5 * Copyright IBM Corp. 2004
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
7 */
8
9#define IN_ARCH_STRING_C 1
10
11#include <linux/types.h>
12#include <linux/module.h>
13
14/*
15 * Helper functions to find the end of a string
16 */
17static inline char *__strend(const char *s)
18{
19 register unsigned long r0 asm("0") = 0;
20
21 asm volatile ("0: srst %0,%1\n"
22 " jo 0b"
23 : "+d" (r0), "+a" (s) : : "cc" );
24 return (char *) r0;
25}
26
27static inline char *__strnend(const char *s, size_t n)
28{
29 register unsigned long r0 asm("0") = 0;
30 const char *p = s + n;
31
32 asm volatile ("0: srst %0,%1\n"
33 " jo 0b"
34 : "+d" (p), "+a" (s) : "d" (r0) : "cc" );
35 return (char *) p;
36}
37
38/**
39 * strlen - Find the length of a string
40 * @s: The string to be sized
41 *
42 * returns the length of @s
43 */
44size_t strlen(const char *s)
45{
46 return __strend(s) - s;
47}
48EXPORT_SYMBOL(strlen);
49
50/**
51 * strnlen - Find the length of a length-limited string
52 * @s: The string to be sized
53 * @n: The maximum number of bytes to search
54 *
55 * returns the minimum of the length of @s and @n
56 */
57size_t strnlen(const char * s, size_t n)
58{
59 return __strnend(s, n) - s;
60}
61EXPORT_SYMBOL(strnlen);
62
63/**
64 * strcpy - Copy a %NUL terminated string
65 * @dest: Where to copy the string to
66 * @src: Where to copy the string from
67 *
68 * returns a pointer to @dest
69 */
70char *strcpy(char *dest, const char *src)
71{
72 register int r0 asm("0") = 0;
73 char *ret = dest;
74
75 asm volatile ("0: mvst %0,%1\n"
76 " jo 0b"
77 : "+&a" (dest), "+&a" (src) : "d" (r0)
78 : "cc", "memory" );
79 return ret;
80}
81EXPORT_SYMBOL(strcpy);
82
83/**
84 * strlcpy - Copy a %NUL terminated string into a sized buffer
85 * @dest: Where to copy the string to
86 * @src: Where to copy the string from
87 * @size: size of destination buffer
88 *
89 * Compatible with *BSD: the result is always a valid
90 * NUL-terminated string that fits in the buffer (unless,
91 * of course, the buffer size is zero). It does not pad
92 * out the result like strncpy() does.
93 */
94size_t strlcpy(char *dest, const char *src, size_t size)
95{
96 size_t ret = __strend(src) - src;
97
98 if (size) {
99 size_t len = (ret >= size) ? size-1 : ret;
100 dest[len] = '\0';
101 memcpy(dest, src, len);
102 }
103 return ret;
104}
105EXPORT_SYMBOL(strlcpy);
106
107/**
108 * strncpy - Copy a length-limited, %NUL-terminated string
109 * @dest: Where to copy the string to
110 * @src: Where to copy the string from
111 * @n: The maximum number of bytes to copy
112 *
113 * The result is not %NUL-terminated if the source exceeds
114 * @n bytes.
115 */
116char *strncpy(char *dest, const char *src, size_t n)
117{
118 size_t len = __strnend(src, n) - src;
119 memset(dest + len, 0, n - len);
120 memcpy(dest, src, len);
121 return dest;
122}
123EXPORT_SYMBOL(strncpy);
124
125/**
126 * strcat - Append one %NUL-terminated string to another
127 * @dest: The string to be appended to
128 * @src: The string to append to it
129 *
130 * returns a pointer to @dest
131 */
132char *strcat(char *dest, const char *src)
133{
134 register int r0 asm("0") = 0;
135 unsigned long dummy;
136 char *ret = dest;
137
138 asm volatile ("0: srst %0,%1\n"
139 " jo 0b\n"
140 "1: mvst %0,%2\n"
141 " jo 1b"
142 : "=&a" (dummy), "+a" (dest), "+a" (src)
143 : "d" (r0), "0" (0UL) : "cc", "memory" );
144 return ret;
145}
146EXPORT_SYMBOL(strcat);
147
148/**
149 * strlcat - Append a length-limited, %NUL-terminated string to another
150 * @dest: The string to be appended to
151 * @src: The string to append to it
152 * @n: The size of the destination buffer.
153 */
154size_t strlcat(char *dest, const char *src, size_t n)
155{
156 size_t dsize = __strend(dest) - dest;
157 size_t len = __strend(src) - src;
158 size_t res = dsize + len;
159
160 if (dsize < n) {
161 dest += dsize;
162 n -= dsize;
163 if (len >= n)
164 len = n - 1;
165 dest[len] = '\0';
166 memcpy(dest, src, len);
167 }
168 return res;
169}
170EXPORT_SYMBOL(strlcat);
171
172/**
173 * strncat - Append a length-limited, %NUL-terminated string to another
174 * @dest: The string to be appended to
175 * @src: The string to append to it
176 * @n: The maximum numbers of bytes to copy
177 *
178 * returns a pointer to @dest
179 *
180 * Note that in contrast to strncpy, strncat ensures the result is
181 * terminated.
182 */
183char *strncat(char *dest, const char *src, size_t n)
184{
185 size_t len = __strnend(src, n) - src;
186 char *p = __strend(dest);
187
188 p[len] = '\0';
189 memcpy(p, src, len);
190 return dest;
191}
192EXPORT_SYMBOL(strncat);
193
194/**
195 * strcmp - Compare two strings
196 * @cs: One string
197 * @ct: Another string
198 *
199 * returns 0 if @cs and @ct are equal,
200 * < 0 if @cs is less than @ct
201 * > 0 if @cs is greater than @ct
202 */
203int strcmp(const char *cs, const char *ct)
204{
205 register int r0 asm("0") = 0;
206 int ret = 0;
207
208 asm volatile ("0: clst %2,%3\n"
209 " jo 0b\n"
210 " je 1f\n"
211 " ic %0,0(%2)\n"
212 " ic %1,0(%3)\n"
213 " sr %0,%1\n"
214 "1:"
215 : "+d" (ret), "+d" (r0), "+a" (cs), "+a" (ct)
216 : : "cc" );
217 return ret;
218}
219EXPORT_SYMBOL(strcmp);
220
221/**
222 * strrchr - Find the last occurrence of a character in a string
223 * @s: The string to be searched
224 * @c: The character to search for
225 */
226char * strrchr(const char * s, int c)
227{
228 size_t len = __strend(s) - s;
229
230 if (len)
231 do {
232 if (s[len] == (char) c)
233 return (char *) s + len;
234 } while (--len > 0);
235 return NULL;
236}
237EXPORT_SYMBOL(strrchr);
238
239/**
240 * strstr - Find the first substring in a %NUL terminated string
241 * @s1: The string to be searched
242 * @s2: The string to search for
243 */
244char * strstr(const char * s1,const char * s2)
245{
246 int l1, l2;
247
248 l2 = __strend(s2) - s2;
249 if (!l2)
250 return (char *) s1;
251 l1 = __strend(s1) - s1;
252 while (l1-- >= l2) {
253 register unsigned long r2 asm("2") = (unsigned long) s1;
254 register unsigned long r3 asm("3") = (unsigned long) l2;
255 register unsigned long r4 asm("4") = (unsigned long) s2;
256 register unsigned long r5 asm("5") = (unsigned long) l2;
257 int cc;
258
259 asm volatile ("0: clcle %1,%3,0\n"
260 " jo 0b\n"
261 " ipm %0\n"
262 " srl %0,28"
263 : "=&d" (cc), "+a" (r2), "+a" (r3),
264 "+a" (r4), "+a" (r5) : : "cc" );
265 if (!cc)
266 return (char *) s1;
267 s1++;
268 }
269 return NULL;
270}
271EXPORT_SYMBOL(strstr);
272
273/**
274 * memchr - Find a character in an area of memory.
275 * @s: The memory area
276 * @c: The byte to search for
277 * @n: The size of the area.
278 *
279 * returns the address of the first occurrence of @c, or %NULL
280 * if @c is not found
281 */
282void *memchr(const void *s, int c, size_t n)
283{
284 register int r0 asm("0") = (char) c;
285 const void *ret = s + n;
286
287 asm volatile ("0: srst %0,%1\n"
288 " jo 0b\n"
289 " jl 1f\n"
290 " la %0,0\n"
291 "1:"
292 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
293 return (void *) ret;
294}
295EXPORT_SYMBOL(memchr);
296
297/**
298 * memcmp - Compare two areas of memory
299 * @cs: One area of memory
300 * @ct: Another area of memory
301 * @count: The size of the area.
302 */
303int memcmp(const void *cs, const void *ct, size_t n)
304{
305 register unsigned long r2 asm("2") = (unsigned long) cs;
306 register unsigned long r3 asm("3") = (unsigned long) n;
307 register unsigned long r4 asm("4") = (unsigned long) ct;
308 register unsigned long r5 asm("5") = (unsigned long) n;
309 int ret;
310
311 asm volatile ("0: clcle %1,%3,0\n"
312 " jo 0b\n"
313 " ipm %0\n"
314 " srl %0,28"
315 : "=&d" (ret), "+a" (r2), "+a" (r3), "+a" (r4), "+a" (r5)
316 : : "cc" );
317 if (ret)
318 ret = *(char *) r2 - *(char *) r4;
319 return ret;
320}
321EXPORT_SYMBOL(memcmp);
322
323/**
324 * memscan - Find a character in an area of memory.
325 * @s: The memory area
326 * @c: The byte to search for
327 * @n: The size of the area.
328 *
329 * returns the address of the first occurrence of @c, or 1 byte past
330 * the area if @c is not found
331 */
332void *memscan(void *s, int c, size_t n)
333{
334 register int r0 asm("0") = (char) c;
335 const void *ret = s + n;
336
337 asm volatile ("0: srst %0,%1\n"
338 " jo 0b\n"
339 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
340 return (void *) ret;
341}
342EXPORT_SYMBOL(memscan);
1/*
2 * arch/s390/lib/string.c
3 * Optimized string functions
4 *
5 * S390 version
6 * Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
8 */
9
10#define IN_ARCH_STRING_C 1
11
12#include <linux/types.h>
13#include <linux/module.h>
14
15/*
16 * Helper functions to find the end of a string
17 */
18static inline char *__strend(const char *s)
19{
20 register unsigned long r0 asm("0") = 0;
21
22 asm volatile ("0: srst %0,%1\n"
23 " jo 0b"
24 : "+d" (r0), "+a" (s) : : "cc" );
25 return (char *) r0;
26}
27
28static inline char *__strnend(const char *s, size_t n)
29{
30 register unsigned long r0 asm("0") = 0;
31 const char *p = s + n;
32
33 asm volatile ("0: srst %0,%1\n"
34 " jo 0b"
35 : "+d" (p), "+a" (s) : "d" (r0) : "cc" );
36 return (char *) p;
37}
38
39/**
40 * strlen - Find the length of a string
41 * @s: The string to be sized
42 *
43 * returns the length of @s
44 */
45size_t strlen(const char *s)
46{
47#if __GNUC__ < 4
48 return __strend(s) - s;
49#else
50 return __builtin_strlen(s);
51#endif
52}
53EXPORT_SYMBOL(strlen);
54
55/**
56 * strnlen - Find the length of a length-limited string
57 * @s: The string to be sized
58 * @n: The maximum number of bytes to search
59 *
60 * returns the minimum of the length of @s and @n
61 */
62size_t strnlen(const char * s, size_t n)
63{
64 return __strnend(s, n) - s;
65}
66EXPORT_SYMBOL(strnlen);
67
68/**
69 * strcpy - Copy a %NUL terminated string
70 * @dest: Where to copy the string to
71 * @src: Where to copy the string from
72 *
73 * returns a pointer to @dest
74 */
75char *strcpy(char *dest, const char *src)
76{
77#if __GNUC__ < 4
78 register int r0 asm("0") = 0;
79 char *ret = dest;
80
81 asm volatile ("0: mvst %0,%1\n"
82 " jo 0b"
83 : "+&a" (dest), "+&a" (src) : "d" (r0)
84 : "cc", "memory" );
85 return ret;
86#else
87 return __builtin_strcpy(dest, src);
88#endif
89}
90EXPORT_SYMBOL(strcpy);
91
92/**
93 * strlcpy - Copy a %NUL terminated string into a sized buffer
94 * @dest: Where to copy the string to
95 * @src: Where to copy the string from
96 * @size: size of destination buffer
97 *
98 * Compatible with *BSD: the result is always a valid
99 * NUL-terminated string that fits in the buffer (unless,
100 * of course, the buffer size is zero). It does not pad
101 * out the result like strncpy() does.
102 */
103size_t strlcpy(char *dest, const char *src, size_t size)
104{
105 size_t ret = __strend(src) - src;
106
107 if (size) {
108 size_t len = (ret >= size) ? size-1 : ret;
109 dest[len] = '\0';
110 __builtin_memcpy(dest, src, len);
111 }
112 return ret;
113}
114EXPORT_SYMBOL(strlcpy);
115
116/**
117 * strncpy - Copy a length-limited, %NUL-terminated string
118 * @dest: Where to copy the string to
119 * @src: Where to copy the string from
120 * @n: The maximum number of bytes to copy
121 *
122 * The result is not %NUL-terminated if the source exceeds
123 * @n bytes.
124 */
125char *strncpy(char *dest, const char *src, size_t n)
126{
127 size_t len = __strnend(src, n) - src;
128 __builtin_memset(dest + len, 0, n - len);
129 __builtin_memcpy(dest, src, len);
130 return dest;
131}
132EXPORT_SYMBOL(strncpy);
133
134/**
135 * strcat - Append one %NUL-terminated string to another
136 * @dest: The string to be appended to
137 * @src: The string to append to it
138 *
139 * returns a pointer to @dest
140 */
141char *strcat(char *dest, const char *src)
142{
143 register int r0 asm("0") = 0;
144 unsigned long dummy;
145 char *ret = dest;
146
147 asm volatile ("0: srst %0,%1\n"
148 " jo 0b\n"
149 "1: mvst %0,%2\n"
150 " jo 1b"
151 : "=&a" (dummy), "+a" (dest), "+a" (src)
152 : "d" (r0), "0" (0UL) : "cc", "memory" );
153 return ret;
154}
155EXPORT_SYMBOL(strcat);
156
157/**
158 * strlcat - Append a length-limited, %NUL-terminated string to another
159 * @dest: The string to be appended to
160 * @src: The string to append to it
161 * @n: The size of the destination buffer.
162 */
163size_t strlcat(char *dest, const char *src, size_t n)
164{
165 size_t dsize = __strend(dest) - dest;
166 size_t len = __strend(src) - src;
167 size_t res = dsize + len;
168
169 if (dsize < n) {
170 dest += dsize;
171 n -= dsize;
172 if (len >= n)
173 len = n - 1;
174 dest[len] = '\0';
175 __builtin_memcpy(dest, src, len);
176 }
177 return res;
178}
179EXPORT_SYMBOL(strlcat);
180
181/**
182 * strncat - Append a length-limited, %NUL-terminated string to another
183 * @dest: The string to be appended to
184 * @src: The string to append to it
185 * @n: The maximum numbers of bytes to copy
186 *
187 * returns a pointer to @dest
188 *
189 * Note that in contrast to strncpy, strncat ensures the result is
190 * terminated.
191 */
192char *strncat(char *dest, const char *src, size_t n)
193{
194 size_t len = __strnend(src, n) - src;
195 char *p = __strend(dest);
196
197 p[len] = '\0';
198 __builtin_memcpy(p, src, len);
199 return dest;
200}
201EXPORT_SYMBOL(strncat);
202
203/**
204 * strcmp - Compare two strings
205 * @cs: One string
206 * @ct: Another string
207 *
208 * returns 0 if @cs and @ct are equal,
209 * < 0 if @cs is less than @ct
210 * > 0 if @cs is greater than @ct
211 */
212int strcmp(const char *cs, const char *ct)
213{
214 register int r0 asm("0") = 0;
215 int ret = 0;
216
217 asm volatile ("0: clst %2,%3\n"
218 " jo 0b\n"
219 " je 1f\n"
220 " ic %0,0(%2)\n"
221 " ic %1,0(%3)\n"
222 " sr %0,%1\n"
223 "1:"
224 : "+d" (ret), "+d" (r0), "+a" (cs), "+a" (ct)
225 : : "cc" );
226 return ret;
227}
228EXPORT_SYMBOL(strcmp);
229
230/**
231 * strrchr - Find the last occurrence of a character in a string
232 * @s: The string to be searched
233 * @c: The character to search for
234 */
235char * strrchr(const char * s, int c)
236{
237 size_t len = __strend(s) - s;
238
239 if (len)
240 do {
241 if (s[len] == (char) c)
242 return (char *) s + len;
243 } while (--len > 0);
244 return NULL;
245}
246EXPORT_SYMBOL(strrchr);
247
248/**
249 * strstr - Find the first substring in a %NUL terminated string
250 * @s1: The string to be searched
251 * @s2: The string to search for
252 */
253char * strstr(const char * s1,const char * s2)
254{
255 int l1, l2;
256
257 l2 = __strend(s2) - s2;
258 if (!l2)
259 return (char *) s1;
260 l1 = __strend(s1) - s1;
261 while (l1-- >= l2) {
262 register unsigned long r2 asm("2") = (unsigned long) s1;
263 register unsigned long r3 asm("3") = (unsigned long) l2;
264 register unsigned long r4 asm("4") = (unsigned long) s2;
265 register unsigned long r5 asm("5") = (unsigned long) l2;
266 int cc;
267
268 asm volatile ("0: clcle %1,%3,0\n"
269 " jo 0b\n"
270 " ipm %0\n"
271 " srl %0,28"
272 : "=&d" (cc), "+a" (r2), "+a" (r3),
273 "+a" (r4), "+a" (r5) : : "cc" );
274 if (!cc)
275 return (char *) s1;
276 s1++;
277 }
278 return NULL;
279}
280EXPORT_SYMBOL(strstr);
281
282/**
283 * memchr - Find a character in an area of memory.
284 * @s: The memory area
285 * @c: The byte to search for
286 * @n: The size of the area.
287 *
288 * returns the address of the first occurrence of @c, or %NULL
289 * if @c is not found
290 */
291void *memchr(const void *s, int c, size_t n)
292{
293 register int r0 asm("0") = (char) c;
294 const void *ret = s + n;
295
296 asm volatile ("0: srst %0,%1\n"
297 " jo 0b\n"
298 " jl 1f\n"
299 " la %0,0\n"
300 "1:"
301 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
302 return (void *) ret;
303}
304EXPORT_SYMBOL(memchr);
305
306/**
307 * memcmp - Compare two areas of memory
308 * @cs: One area of memory
309 * @ct: Another area of memory
310 * @count: The size of the area.
311 */
312int memcmp(const void *cs, const void *ct, size_t n)
313{
314 register unsigned long r2 asm("2") = (unsigned long) cs;
315 register unsigned long r3 asm("3") = (unsigned long) n;
316 register unsigned long r4 asm("4") = (unsigned long) ct;
317 register unsigned long r5 asm("5") = (unsigned long) n;
318 int ret;
319
320 asm volatile ("0: clcle %1,%3,0\n"
321 " jo 0b\n"
322 " ipm %0\n"
323 " srl %0,28"
324 : "=&d" (ret), "+a" (r2), "+a" (r3), "+a" (r4), "+a" (r5)
325 : : "cc" );
326 if (ret)
327 ret = *(char *) r2 - *(char *) r4;
328 return ret;
329}
330EXPORT_SYMBOL(memcmp);
331
332/**
333 * memscan - Find a character in an area of memory.
334 * @s: The memory area
335 * @c: The byte to search for
336 * @n: The size of the area.
337 *
338 * returns the address of the first occurrence of @c, or 1 byte past
339 * the area if @c is not found
340 */
341void *memscan(void *s, int c, size_t n)
342{
343 register int r0 asm("0") = (char) c;
344 const void *ret = s + n;
345
346 asm volatile ("0: srst %0,%1\n"
347 " jo 0b\n"
348 : "+a" (ret), "+&a" (s) : "d" (r0) : "cc" );
349 return (void *) ret;
350}
351EXPORT_SYMBOL(memscan);
352
353/**
354 * memcpy - Copy one area of memory to another
355 * @dest: Where to copy to
356 * @src: Where to copy from
357 * @n: The size of the area.
358 *
359 * returns a pointer to @dest
360 */
361void *memcpy(void *dest, const void *src, size_t n)
362{
363 return __builtin_memcpy(dest, src, n);
364}
365EXPORT_SYMBOL(memcpy);
366
367/**
368 * memset - Fill a region of memory with the given value
369 * @s: Pointer to the start of the area.
370 * @c: The byte to fill the area with
371 * @n: The size of the area.
372 *
373 * returns a pointer to @s
374 */
375void *memset(void *s, int c, size_t n)
376{
377 char *xs;
378
379 if (c == 0)
380 return __builtin_memset(s, 0, n);
381
382 xs = (char *) s;
383 if (n > 0)
384 do {
385 *xs++ = c;
386 } while (--n > 0);
387 return s;
388}
389EXPORT_SYMBOL(memset);