1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
|
#ifndef BITS_STRING_H
#define BITS_STRING_H
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/** @file
*
* String functions
*
*/
extern void arm64_bzero ( void *dest, size_t len );
extern void arm64_memset ( void *dest, size_t len, int character );
extern void arm64_memcpy ( void *dest, const void *src, size_t len );
extern void arm64_memmove_forwards ( void *dest, const void *src, size_t len );
extern void arm64_memmove_backwards ( void *dest, const void *src, size_t len );
extern void arm64_memmove ( void *dest, const void *src, size_t len );
/**
* Fill memory region
*
* @v dest Destination region
* @v character Fill character
* @v len Length
* @ret dest Destination region
*/
static inline __attribute__ (( always_inline )) void *
memset ( void *dest, int character, size_t len ) {
/* Allow gcc to generate inline "stX xzr" instructions for
* small, constant lengths.
*/
if ( __builtin_constant_p ( character ) && ( character == 0 ) &&
__builtin_constant_p ( len ) && ( len <= 64 ) ) {
__builtin_memset ( dest, 0, len );
return dest;
}
/* For zeroing larger or non-constant lengths, use the
* optimised variable-length zeroing code.
*/
if ( __builtin_constant_p ( character ) && ( character == 0 ) ) {
arm64_bzero ( dest, len );
return dest;
}
/* Not necessarily zeroing: use basic variable-length code */
arm64_memset ( dest, len, character );
return dest;
}
/**
* Copy memory region
*
* @v dest Destination region
* @v src Source region
* @v len Length
* @ret dest Destination region
*/
static inline __attribute__ (( always_inline )) void *
memcpy ( void *dest, const void *src, size_t len ) {
/* Allow gcc to generate inline "ldX"/"stX" instructions for
* small, constant lengths.
*/
if ( __builtin_constant_p ( len ) && ( len <= 64 ) ) {
__builtin_memcpy ( dest, src, len );
return dest;
}
/* Otherwise, use variable-length code */
arm64_memcpy ( dest, src, len );
return dest;
}
/**
* Copy (possibly overlapping) memory region
*
* @v dest Destination region
* @v src Source region
* @v len Length
* @ret dest Destination region
*/
static inline __attribute__ (( always_inline )) void *
memmove ( void *dest, const void *src, size_t len ) {
ssize_t offset = ( dest - src );
/* If required direction of copy is known at build time, then
* use the appropriate forwards/backwards copy directly.
*/
if ( __builtin_constant_p ( offset ) ) {
if ( offset <= 0 ) {
arm64_memmove_forwards ( dest, src, len );
return dest;
} else {
arm64_memmove_backwards ( dest, src, len );
return dest;
}
}
/* Otherwise, use ambidirectional copy */
arm64_memmove ( dest, src, len );
return dest;
}
#endif /* BITS_STRING_H */
|
