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author | Thomas Martitz <kugel@rockbox.org> | 2010-05-06 21:04:40 +0000 |
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committer | Thomas Martitz <kugel@rockbox.org> | 2010-05-06 21:04:40 +0000 |
commit | 50a6ca39ad4ed01922aa4f755f0ca579788226cf (patch) | |
tree | c7881b015b220558167310345b162324c96be15a /firmware/libc/memcmp.c | |
parent | adb506df14aded06ed6e9ebf8540e6fd383ffd6a (diff) | |
download | rockbox-50a6ca39ad4ed01922aa4f755f0ca579788226cf.tar.gz rockbox-50a6ca39ad4ed01922aa4f755f0ca579788226cf.zip |
Move c/h files implementing/defining standard library stuff into a new libc directory, also standard'ify some parts of the code base (almost entirely #include fixes).
This is to a) to cleanup firmware/common and firmware/include a bit, but also b) for Rockbox as an application which should use the host system's c library and headers, separating makes it easy to exclude our files from the build.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25850 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/libc/memcmp.c')
-rw-r--r-- | firmware/libc/memcmp.c | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/firmware/libc/memcmp.c b/firmware/libc/memcmp.c new file mode 100644 index 0000000000..1535fcf5b5 --- /dev/null +++ b/firmware/libc/memcmp.c | |||
@@ -0,0 +1,113 @@ | |||
1 | /* | ||
2 | FUNCTION | ||
3 | <<memcmp>>---compare two memory areas | ||
4 | |||
5 | INDEX | ||
6 | memcmp | ||
7 | |||
8 | ANSI_SYNOPSIS | ||
9 | #include <string.h> | ||
10 | int memcmp(const void *<[s1]>, const void *<[s2]>, size_t <[n]>); | ||
11 | |||
12 | TRAD_SYNOPSIS | ||
13 | #include <string.h> | ||
14 | int memcmp(<[s1]>, <[s2]>, <[n]>) | ||
15 | void *<[s1]>; | ||
16 | void *<[s2]>; | ||
17 | size_t <[n]>; | ||
18 | |||
19 | DESCRIPTION | ||
20 | This function compares not more than <[n]> characters of the | ||
21 | object pointed to by <[s1]> with the object pointed to by <[s2]>. | ||
22 | |||
23 | |||
24 | RETURNS | ||
25 | The function returns an integer greater than, equal to or | ||
26 | less than zero according to whether the object pointed to by | ||
27 | <[s1]> is greater than, equal to or less than the object | ||
28 | pointed to by <[s2]>. | ||
29 | |||
30 | PORTABILITY | ||
31 | <<memcmp>> is ANSI C. | ||
32 | |||
33 | <<memcmp>> requires no supporting OS subroutines. | ||
34 | |||
35 | QUICKREF | ||
36 | memcmp ansi pure | ||
37 | */ | ||
38 | |||
39 | #include <string.h> | ||
40 | |||
41 | |||
42 | /* Nonzero if either X or Y is not aligned on a "long" boundary. */ | ||
43 | #define UNALIGNED(X, Y) \ | ||
44 | (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) | ||
45 | |||
46 | /* How many bytes are copied each iteration of the word copy loop. */ | ||
47 | #define LBLOCKSIZE (sizeof (long)) | ||
48 | |||
49 | /* Threshhold for punting to the byte copier. */ | ||
50 | #define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE) | ||
51 | |||
52 | int | ||
53 | _DEFUN (memcmp, (m1, m2, n), | ||
54 | _CONST _PTR m1 _AND | ||
55 | _CONST _PTR m2 _AND | ||
56 | size_t n) | ||
57 | { | ||
58 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) | ||
59 | unsigned char *s1 = (unsigned char *) m1; | ||
60 | unsigned char *s2 = (unsigned char *) m2; | ||
61 | |||
62 | while (n--) | ||
63 | { | ||
64 | if (*s1 != *s2) | ||
65 | { | ||
66 | return *s1 - *s2; | ||
67 | } | ||
68 | s1++; | ||
69 | s2++; | ||
70 | } | ||
71 | return 0; | ||
72 | #else | ||
73 | unsigned char *s1 = (unsigned char *) m1; | ||
74 | unsigned char *s2 = (unsigned char *) m2; | ||
75 | unsigned long *a1; | ||
76 | unsigned long *a2; | ||
77 | |||
78 | /* If the size is too small, or either pointer is unaligned, | ||
79 | then we punt to the byte compare loop. Hopefully this will | ||
80 | not turn up in inner loops. */ | ||
81 | if (!TOO_SMALL(n) && !UNALIGNED(s1,s2)) | ||
82 | { | ||
83 | /* Otherwise, load and compare the blocks of memory one | ||
84 | word at a time. */ | ||
85 | a1 = (unsigned long*) s1; | ||
86 | a2 = (unsigned long*) s2; | ||
87 | while (n >= LBLOCKSIZE) | ||
88 | { | ||
89 | if (*a1 != *a2) | ||
90 | break; | ||
91 | a1++; | ||
92 | a2++; | ||
93 | n -= LBLOCKSIZE; | ||
94 | } | ||
95 | |||
96 | /* check m mod LBLOCKSIZE remaining characters */ | ||
97 | |||
98 | s1 = (unsigned char*)a1; | ||
99 | s2 = (unsigned char*)a2; | ||
100 | } | ||
101 | |||
102 | while (n--) | ||
103 | { | ||
104 | if (*s1 != *s2) | ||
105 | return *s1 - *s2; | ||
106 | s1++; | ||
107 | s2++; | ||
108 | } | ||
109 | |||
110 | return 0; | ||
111 | #endif /* not PREFER_SIZE_OVER_SPEED */ | ||
112 | } | ||
113 | |||