1 /*
2 * Copyright (c) 2008 ARM Ltd
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the company may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
22 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
24 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
25 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /* For GLIBC:
30 #include <string.h>
31 #include <memcopy.h>
32
33 #undef strcmp
34 */
35
36 #ifdef __thumb2__
37 #define magic1(REG) "#0x01010101"
38 #define magic2(REG) "#0x80808080"
39 #else
40 #define magic1(REG) #REG
41 #define magic2(REG) #REG ", lsl #7"
42 #endif
43
44 char* __attribute__((naked))
strcpy(char * dst,const char * src)45 strcpy (char* dst, const char* src)
46 {
47 asm (
48 #if !(defined(__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED) || \
49 (defined (__thumb__) && !defined (__thumb2__)))
50 "pld [r1, #0]\n\t"
51 "eor r2, r0, r1\n\t"
52 "mov ip, r0\n\t"
53 "tst r2, #3\n\t"
54 "bne 4f\n\t"
55 "tst r1, #3\n\t"
56 "bne 3f\n"
57 "5:\n\t"
58 #ifndef __thumb2__
59 "str r5, [sp, #-4]!\n\t"
60 "mov r5, #0x01\n\t"
61 "orr r5, r5, r5, lsl #8\n\t"
62 "orr r5, r5, r5, lsl #16\n\t"
63 #endif
64
65 "str r4, [sp, #-4]!\n\t"
66 "tst r1, #4\n\t"
67 "ldr r3, [r1], #4\n\t"
68 "beq 2f\n\t"
69 "sub r2, r3, "magic1(r5)"\n\t"
70 "bics r2, r2, r3\n\t"
71 "tst r2, "magic2(r5)"\n\t"
72 "itt eq\n\t"
73 "streq r3, [ip], #4\n\t"
74 "ldreq r3, [r1], #4\n"
75 "bne 1f\n\t"
76 /* Inner loop. We now know that r1 is 64-bit aligned, so we
77 can safely fetch up to two words. This allows us to avoid
78 load stalls. */
79 ".p2align 2\n"
80 "2:\n\t"
81 "pld [r1, #8]\n\t"
82 "ldr r4, [r1], #4\n\t"
83 "sub r2, r3, "magic1(r5)"\n\t"
84 "bics r2, r2, r3\n\t"
85 "tst r2, "magic2(r5)"\n\t"
86 "sub r2, r4, "magic1(r5)"\n\t"
87 "bne 1f\n\t"
88 "str r3, [ip], #4\n\t"
89 "bics r2, r2, r4\n\t"
90 "tst r2, "magic2(r5)"\n\t"
91 "itt eq\n\t"
92 "ldreq r3, [r1], #4\n\t"
93 "streq r4, [ip], #4\n\t"
94 "beq 2b\n\t"
95 "mov r3, r4\n"
96 "1:\n\t"
97 #ifdef __ARMEB__
98 "rors r3, r3, #24\n\t"
99 #endif
100 "strb r3, [ip], #1\n\t"
101 "tst r3, #0xff\n\t"
102 #ifdef __ARMEL__
103 "ror r3, r3, #8\n\t"
104 #endif
105 "bne 1b\n\t"
106 "ldr r4, [sp], #4\n\t"
107 #ifndef __thumb2__
108 "ldr r5, [sp], #4\n\t"
109 #endif
110 "BX LR\n"
111
112 /* Strings have the same offset from word alignment, but it's
113 not zero. */
114 "3:\n\t"
115 "tst r1, #1\n\t"
116 "beq 1f\n\t"
117 "ldrb r2, [r1], #1\n\t"
118 "strb r2, [ip], #1\n\t"
119 "cmp r2, #0\n\t"
120 "it eq\n"
121 "BXEQ LR\n"
122 "1:\n\t"
123 "tst r1, #2\n\t"
124 "beq 5b\n\t"
125 "ldrh r2, [r1], #2\n\t"
126 #ifdef __ARMEB__
127 "tst r2, #0xff00\n\t"
128 "iteet ne\n\t"
129 "strneh r2, [ip], #2\n\t"
130 "lsreq r2, r2, #8\n\t"
131 "streqb r2, [ip]\n\t"
132 "tstne r2, #0xff\n\t"
133 #else
134 "tst r2, #0xff\n\t"
135 "itet ne\n\t"
136 "strneh r2, [ip], #2\n\t"
137 "streqb r2, [ip]\n\t"
138 "tstne r2, #0xff00\n\t"
139 #endif
140 "bne 5b\n\t"
141 "BX LR\n"
142
143 /* src and dst do not have a common word-alignement. Fall back to
144 byte copying. */
145 "4:\n\t"
146 "ldrb r2, [r1], #1\n\t"
147 "strb r2, [ip], #1\n\t"
148 "cmp r2, #0\n\t"
149 "bne 4b\n\t"
150 "BX LR"
151
152 #elif !defined (__thumb__) || defined (__thumb2__)
153 "mov r3, r0\n\t"
154 "1:\n\t"
155 "ldrb r2, [r1], #1\n\t"
156 "strb r2, [r3], #1\n\t"
157 "cmp r2, #0\n\t"
158 "bne 1b\n\t"
159 "BX LR"
160 #else
161 "mov r3, r0\n\t"
162 "1:\n\t"
163 "ldrb r2, [r1]\n\t"
164 "add r1, r1, #1\n\t"
165 "strb r2, [r3]\n\t"
166 "add r3, r3, #1\n\t"
167 "cmp r2, #0\n\t"
168 "bne 1b\n\t"
169 "BX LR"
170 #endif
171 );
172 }
173 /* For GLIBC: libc_hidden_builtin_def (strcpy) */
174