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 <string.h>
62 #include <limits.h>
63
64 /* Nonzero if either X or Y is not aligned on a "long" boundary. */
65 #define UNALIGNED(X, Y) \
66 (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
67
68 /* DETECTNULL returns nonzero if (long)X contains a NULL byte. */
69 #if LONG_MAX == 2147483647L
70 #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080)
71 #else
72 #if LONG_MAX == 9223372036854775807L
73 #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080)
74 #else
75 #error long int is not a 32bit or 64bit type.
76 #endif
77 #endif
78
79 #ifndef DETECTNULL
80 #error long int is not a 32bit or 64bit byte
81 #endif
82
83 int
strcmp(const char * s1,const char * s2)84 strcmp (const char *s1,
85 const char *s2)
86 {
87
88 #ifndef HAVE_HW_PCMP
89
90 #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
91 while (*s1 != '\0' && *s1 == *s2)
92 {
93 s1++;
94 s2++;
95 }
96
97 return (*(unsigned char *) s1) - (*(unsigned char *) s2);
98 #else
99 unsigned long *a1;
100 unsigned long *a2;
101
102 /* If s1 or s2 are unaligned, then compare bytes. */
103 if (!UNALIGNED (s1, s2))
104 {
105 /* If s1 and s2 are word-aligned, compare them a word at a time. */
106 a1 = (unsigned long*)s1;
107 a2 = (unsigned long*)s2;
108 while (*a1 == *a2)
109 {
110 /* To get here, *a1 == *a2, thus if we find a null in *a1,
111 then the strings must be equal, so return zero. */
112 if (DETECTNULL (*a1))
113 return 0;
114
115 a1++;
116 a2++;
117 }
118
119 /* A difference was detected in last few bytes of s1, so search bytewise */
120 s1 = (char*)a1;
121 s2 = (char*)a2;
122 }
123
124 while (*s1 != '\0' && *s1 == *s2)
125 {
126 s1++;
127 s2++;
128 }
129 return (*(unsigned char *) s1) - (*(unsigned char *) s2);
130 #endif /* not PREFER_SIZE_OVER_SPEED */
131
132 #else
133
134 #include "mb_endian.h"
135
136 __asm__ volatile (" \n\
137 or r9, r0, r0 /* Index register */\n\
138 check_alignment: \n\
139 andi r3, r5, 3 \n\
140 andi r4, r6, 3 \n\
141 bnei r3, try_align_args \n\
142 bnei r4, regular_strcmp /* At this point we don't have a choice */ \n\
143 cmp_loop: \n"
144 LOAD4BYTES("r3", "r5", "r9")
145 LOAD4BYTES("r4", "r6", "r9")
146 " \n\
147 pcmpbf r7, r3, r0 /* See if there is Null byte */ \n\
148 bnei r7, end_cmp_loop /* IF yes (r7 > 0) use byte compares in end_cmp_loop */ \n\
149 cmpu r7, r4, r3 /* ELSE compare whole word */ \n\
150 bnei r7, end_cmp \n\
151 brid cmp_loop \n\
152 addik r9, r9, 4 /* delay slot */ \n\
153 end_cmp_loop: \n\
154 lbu r3, r5, r9 /* byte compare loop */ \n\
155 lbu r4, r6, r9 \n\
156 cmpu r7, r4, r3 /* Compare bytes */ \n\
157 bnei r7, end_cmp_early \n\
158 bneid r3, end_cmp_loop /* If reached null on one string, terminate */ \n\
159 addik r9, r9, 1 /* delay slot */ \n\
160 end_cmp_early: \n\
161 rtsd r15, 8 \n\
162 or r3, r0, r7 \n\
163 try_align_args: \n\
164 xor r7, r4, r3 \n\
165 bnei r7, regular_strcmp /* cannot align args */ \n\
166 rsubik r10, r3, 4 /* Number of initial bytes to align */ \n\
167 align_loop: \n\
168 lbu r3, r5, r9 \n\
169 lbu r4, r6, r9 \n\
170 cmpu r7, r4, r3 \n\
171 bnei r7, end_cmp \n\
172 beqi r3, end_cmp \n\
173 addik r10, r10, -1 \n\
174 beqid r10, cmp_loop \n\
175 addik r9, r9, 1 \n\
176 bri align_loop \n\
177 regular_strcmp: \n\
178 lbu r3, r5, r9 \n\
179 lbu r4, r6, r9 \n\
180 cmpu r7, r4, r3 \n\
181 bnei r7, end_cmp \n\
182 beqi r3, end_cmp \n\
183 brid regular_strcmp \n\
184 addik r9, r9, 1 \n\
185 end_cmp: \n\
186 rtsd r15, 8 \n\
187 or r3, r0, r7 /* Return strcmp result */");
188
189 #endif /* ! HAVE_HW_PCMP */
190 }
191
192
