1 /* Copyright (c) 2009 Xilinx, Inc. All rights reserved.
2
3 Redistribution and use in source and binary forms, with or without
4 modification, are permitted provided that the following conditions are
5 met:
6
7 1. Redistributions source code must retain the above copyright notice,
8 this list of conditions and the following disclaimer.
9
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
14 3. Neither the name of Xilinx nor the names of its contributors may be
15 used to endorse or promote products derived from this software without
16 specific prior written permission.
17
18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS
19 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
20 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
21 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
24 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29
30
31 FUNCTION
32 <<strcmp>>---character string compare
33
34 INDEX
35 strcmp
36
37 SYNOPSIS
38 #include <string.h>
39 int strcmp(const char *<[a]>, const char *<[b]>);
40
41 DESCRIPTION
42 <<strcmp>> compares the string at <[a]> to
43 the string at <[b]>.
44
45 RETURNS
46 If <<*<[a]>>> sorts lexicographically after <<*<[b]>>>,
47 <<strcmp>> returns a number greater than zero. If the two
48 strings match, <<strcmp>> returns zero. If <<*<[a]>>>
49 sorts lexicographically before <<*<[b]>>>, <<strcmp>> returns a
50 number less than zero.
51
52 PORTABILITY
53 <<strcmp>> is ANSI C.
54
55 <<strcmp>> requires no supporting OS subroutines.
56
57 QUICKREF
58 strcmp ansi pure
59 */
60
61 #include <picolibc.h>
62
63 #include <string.h>
64 #include <limits.h>
65
66 /* Nonzero if either X or Y is not aligned on a "long" boundary. */
67 #define UNALIGNED(X, Y) \
68 (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
69
70 /* DETECTNULL returns nonzero if (long)X contains a NULL byte. */
71 #if LONG_MAX == 2147483647L
72 #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
73 #else
74 #if LONG_MAX == 9223372036854775807L
75 #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
76 #else
77 #error long int is not a 32bit or 64bit type.
78 #endif
79 #endif
80
81 #ifndef DETECTNULL
82 #error long int is not a 32bit or 64bit byte
83 #endif
84
85 int
strcmp(const char * s1,const char * s2)86 strcmp (const char *s1,
87 const char *s2)
88 {
89
90 #ifndef HAVE_HW_PCMP
91
92 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
93 while (*s1 != '\0' && *s1 == *s2)
94 {
95 s1++;
96 s2++;
97 }
98
99 return (*(unsigned char *) s1) - (*(unsigned char *) s2);
100 #else
101 unsigned long *a1;
102 unsigned long *a2;
103
104 /* If s1 or s2 are unaligned, then compare bytes. */
105 if (!UNALIGNED (s1, s2))
106 {
107 /* If s1 and s2 are word-aligned, compare them a word at a time. */
108 a1 = (unsigned long*)s1;
109 a2 = (unsigned long*)s2;
110 while (*a1 == *a2)
111 {
112 /* To get here, *a1 == *a2, thus if we find a null in *a1,
113 then the strings must be equal, so return zero. */
114 if (DETECTNULL (*a1))
115 return 0;
116
117 a1++;
118 a2++;
119 }
120
121 /* A difference was detected in last few bytes of s1, so search bytewise */
122 s1 = (char*)a1;
123 s2 = (char*)a2;
124 }
125
126 while (*s1 != '\0' && *s1 == *s2)
127 {
128 s1++;
129 s2++;
130 }
131 return (*(unsigned char *) s1) - (*(unsigned char *) s2);
132 #endif /* not PREFER_SIZE_OVER_SPEED */
133
134 #else
135
136 #include "mb_endian.h"
137
138 __asm__ volatile (" \n\
139 or r9, r0, r0 /* Index register */\n\
140 check_alignment: \n\
141 andi r3, r5, 3 \n\
142 andi r4, r6, 3 \n\
143 bnei r3, try_align_args \n\
144 bnei r4, regular_strcmp /* At this point we don't have a choice */ \n\
145 cmp_loop: \n"
146 LOAD4BYTES("r3", "r5", "r9")
147 LOAD4BYTES("r4", "r6", "r9")
148 " \n\
149 pcmpbf r7, r3, r0 /* See if there is Null byte */ \n\
150 bnei r7, end_cmp_loop /* IF yes (r7 > 0) use byte compares in end_cmp_loop */ \n\
151 cmpu r7, r4, r3 /* ELSE compare whole word */ \n\
152 bnei r7, end_cmp \n\
153 brid cmp_loop \n\
154 addik r9, r9, 4 /* delay slot */ \n\
155 end_cmp_loop: \n\
156 lbu r3, r5, r9 /* byte compare loop */ \n\
157 lbu r4, r6, r9 \n\
158 cmpu r7, r4, r3 /* Compare bytes */ \n\
159 bnei r7, end_cmp_early \n\
160 bneid r3, end_cmp_loop /* If reached null on one string, terminate */ \n\
161 addik r9, r9, 1 /* delay slot */ \n\
162 end_cmp_early: \n\
163 rtsd r15, 8 \n\
164 or r3, r0, r7 \n\
165 try_align_args: \n\
166 xor r7, r4, r3 \n\
167 bnei r7, regular_strcmp /* cannot align args */ \n\
168 rsubik r10, r3, 4 /* Number of initial bytes to align */ \n\
169 align_loop: \n\
170 lbu r3, r5, r9 \n\
171 lbu r4, r6, r9 \n\
172 cmpu r7, r4, r3 \n\
173 bnei r7, end_cmp \n\
174 beqi r3, end_cmp \n\
175 addik r10, r10, -1 \n\
176 beqid r10, cmp_loop \n\
177 addik r9, r9, 1 \n\
178 bri align_loop \n\
179 regular_strcmp: \n\
180 lbu r3, r5, r9 \n\
181 lbu r4, r6, r9 \n\
182 cmpu r7, r4, r3 \n\
183 bnei r7, end_cmp \n\
184 beqi r3, end_cmp \n\
185 brid regular_strcmp \n\
186 addik r9, r9, 1 \n\
187 end_cmp: \n\
188 rtsd r15, 8 \n\
189 or r3, r0, r7 /* Return strcmp result */");
190
191 #endif /* ! HAVE_HW_PCMP */
192 }
193
194
