• Home
  • History
  • Annotate
  • Line#
  • Navigate
  • Raw
  • Download
  • only in /asuswrt-rt-n18u-9.0.0.4.380.2695/release/src-rt-6.x.4708/linux/linux-2.6.36/arch/alpha/include/asm/
1#ifndef _ALPHA_SWAB_H
2#define _ALPHA_SWAB_H
3
4#include <linux/types.h>
5#include <linux/compiler.h>
6#include <asm/compiler.h>
7
8#ifdef __GNUC__
9
10static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
11{
12	/*
13	 * Unfortunately, we can't use the 6 instruction sequence
14	 * on ev6 since the latency of the UNPKBW is 3, which is
15	 * pretty hard to hide.  Just in case a future implementation
16	 * has a lower latency, here's the sequence (also by Mike Burrows)
17	 *
18	 * UNPKBW a0, v0       v0: 00AA00BB00CC00DD
19	 * SLL v0, 24, a0      a0: BB00CC00DD000000
20	 * BIS v0, a0, a0      a0: BBAACCBBDDCC00DD
21	 * EXTWL a0, 6, v0     v0: 000000000000BBAA
22	 * ZAP a0, 0xf3, a0    a0: 00000000DDCC0000
23	 * ADDL a0, v0, v0     v0: ssssssssDDCCBBAA
24	 */
25
26	__u64 t0, t1, t2, t3;
27
28	t0 = __kernel_inslh(x, 7);	/* t0 : 0000000000AABBCC */
29	t1 = __kernel_inswl(x, 3);	/* t1 : 000000CCDD000000 */
30	t1 |= t0;			/* t1 : 000000CCDDAABBCC */
31	t2 = t1 >> 16;			/* t2 : 0000000000CCDDAA */
32	t0 = t1 & 0xFF00FF00;		/* t0 : 00000000DD00BB00 */
33	t3 = t2 & 0x00FF00FF;		/* t3 : 0000000000CC00AA */
34	t1 = t0 + t3;			/* t1 : ssssssssDDCCBBAA */
35
36	return t1;
37}
38#define __arch_swab32 __arch_swab32
39
40#endif /* __GNUC__ */
41
42#endif /* _ALPHA_SWAB_H */
43