diff options
author | Björn Stenberg <bjorn@haxx.se> | 2002-05-30 21:03:17 +0000 |
---|---|---|
committer | Björn Stenberg <bjorn@haxx.se> | 2002-05-30 21:03:17 +0000 |
commit | b69338f9f8ae2ae957949a0f4af9749ebb4adc3f (patch) | |
tree | c29019589ce21007d1ff99dd74d3115f19dbd3f4 /firmware/common/memcpy.c | |
parent | 80361f88818ad1ce2ebc00a10f7aa8de1605b3a5 (diff) | |
download | rockbox-b69338f9f8ae2ae957949a0f4af9749ebb4adc3f.tar.gz rockbox-b69338f9f8ae2ae957949a0f4af9749ebb4adc3f.zip |
Added code from libc instead of requiring newlib
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@835 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/common/memcpy.c')
-rw-r--r-- | firmware/common/memcpy.c | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/firmware/common/memcpy.c b/firmware/common/memcpy.c new file mode 100644 index 0000000000..5336f25a91 --- /dev/null +++ b/firmware/common/memcpy.c | |||
@@ -0,0 +1,111 @@ | |||
1 | /* | ||
2 | FUNCTION | ||
3 | <<memcpy>>---copy memory regions | ||
4 | |||
5 | ANSI_SYNOPSIS | ||
6 | #include <string.h> | ||
7 | void* memcpy(void *<[out]>, const void *<[in]>, size_t <[n]>); | ||
8 | |||
9 | TRAD_SYNOPSIS | ||
10 | void *memcpy(<[out]>, <[in]>, <[n]> | ||
11 | void *<[out]>; | ||
12 | void *<[in]>; | ||
13 | size_t <[n]>; | ||
14 | |||
15 | DESCRIPTION | ||
16 | This function copies <[n]> bytes from the memory region | ||
17 | pointed to by <[in]> to the memory region pointed to by | ||
18 | <[out]>. | ||
19 | |||
20 | If the regions overlap, the behavior is undefined. | ||
21 | |||
22 | RETURNS | ||
23 | <<memcpy>> returns a pointer to the first byte of the <[out]> | ||
24 | region. | ||
25 | |||
26 | PORTABILITY | ||
27 | <<memcpy>> is ANSI C. | ||
28 | |||
29 | <<memcpy>> requires no supporting OS subroutines. | ||
30 | |||
31 | QUICKREF | ||
32 | memcpy ansi pure | ||
33 | */ | ||
34 | |||
35 | #include <_ansi.h> | ||
36 | #include <stddef.h> | ||
37 | #include <limits.h> | ||
38 | |||
39 | /* Nonzero if either X or Y is not aligned on a "long" boundary. */ | ||
40 | #define UNALIGNED(X, Y) \ | ||
41 | (((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1))) | ||
42 | |||
43 | /* How many bytes are copied each iteration of the 4X unrolled loop. */ | ||
44 | #define BIGBLOCKSIZE (sizeof (long) << 2) | ||
45 | |||
46 | /* How many bytes are copied each iteration of the word copy loop. */ | ||
47 | #define LITTLEBLOCKSIZE (sizeof (long)) | ||
48 | |||
49 | /* Threshhold for punting to the byte copier. */ | ||
50 | #define TOO_SMALL(LEN) ((LEN) < BIGBLOCKSIZE) | ||
51 | |||
52 | _PTR | ||
53 | _DEFUN (memcpy, (dst0, src0, len0), | ||
54 | _PTR dst0 _AND | ||
55 | _CONST _PTR src0 _AND | ||
56 | size_t len0) | ||
57 | { | ||
58 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) | ||
59 | char *dst = (char *) dst0; | ||
60 | char *src = (char *) src0; | ||
61 | |||
62 | _PTR save = dst0; | ||
63 | |||
64 | while (len0--) | ||
65 | { | ||
66 | *dst++ = *src++; | ||
67 | } | ||
68 | |||
69 | return save; | ||
70 | #else | ||
71 | char *dst = dst0; | ||
72 | _CONST char *src = src0; | ||
73 | long *aligned_dst; | ||
74 | _CONST long *aligned_src; | ||
75 | int len = len0; | ||
76 | |||
77 | /* If the size is small, or either SRC or DST is unaligned, | ||
78 | then punt into the byte copy loop. This should be rare. */ | ||
79 | if (!TOO_SMALL(len) && !UNALIGNED (src, dst)) | ||
80 | { | ||
81 | aligned_dst = (long*)dst; | ||
82 | aligned_src = (long*)src; | ||
83 | |||
84 | /* Copy 4X long words at a time if possible. */ | ||
85 | while (len >= BIGBLOCKSIZE) | ||
86 | { | ||
87 | *aligned_dst++ = *aligned_src++; | ||
88 | *aligned_dst++ = *aligned_src++; | ||
89 | *aligned_dst++ = *aligned_src++; | ||
90 | *aligned_dst++ = *aligned_src++; | ||
91 | len -= BIGBLOCKSIZE; | ||
92 | } | ||
93 | |||
94 | /* Copy one long word at a time if possible. */ | ||
95 | while (len >= LITTLEBLOCKSIZE) | ||
96 | { | ||
97 | *aligned_dst++ = *aligned_src++; | ||
98 | len -= LITTLEBLOCKSIZE; | ||
99 | } | ||
100 | |||
101 | /* Pick up any residual with a byte copier. */ | ||
102 | dst = (char*)aligned_dst; | ||
103 | src = (char*)aligned_src; | ||
104 | } | ||
105 | |||
106 | while (len--) | ||
107 | *dst++ = *src++; | ||
108 | |||
109 | return dst0; | ||
110 | #endif /* not PREFER_SIZE_OVER_SPEED */ | ||
111 | } | ||