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
|
#ifndef _ALPHA_BYTEORDER_H
#define _ALPHA_BYTEORDER_H
#include <asm/types.h>
#include <linux/compiler.h>
#include <asm/compiler.h>
#ifdef __GNUC__
static inline __attribute_const__ __u32 __arch__swab32(__u32 x)
{
/*
* Unfortunately, we can't use the 6 instruction sequence
* on ev6 since the latency of the UNPKBW is 3, which is
* pretty hard to hide. Just in case a future implementation
* has a lower latency, here's the sequence (also by Mike Burrows)
*
* UNPKBW a0, v0 v0: 00AA00BB00CC00DD
* SLL v0, 24, a0 a0: BB00CC00DD000000
* BIS v0, a0, a0 a0: BBAACCBBDDCC00DD
* EXTWL a0, 6, v0 v0: 000000000000BBAA
* ZAP a0, 0xf3, a0 a0: 00000000DDCC0000
* ADDL a0, v0, v0 v0: ssssssssDDCCBBAA
*/
__u64 t0, t1, t2, t3;
t0 = __kernel_inslh(x, 7); /* t0 : 0000000000AABBCC */
t1 = __kernel_inswl(x, 3); /* t1 : 000000CCDD000000 */
t1 |= t0; /* t1 : 000000CCDDAABBCC */
t2 = t1 >> 16; /* t2 : 0000000000CCDDAA */
t0 = t1 & 0xFF00FF00; /* t0 : 00000000DD00BB00 */
t3 = t2 & 0x00FF00FF; /* t3 : 0000000000CC00AA */
t1 = t0 + t3; /* t1 : ssssssssDDCCBBAA */
return t1;
}
#define __arch__swab32 __arch__swab32
#endif /* __GNUC__ */
#define __BYTEORDER_HAS_U64__
#include <linux/byteorder/little_endian.h>
#endif /* _ALPHA_BYTEORDER_H */
|
