44 lines
1.2 KiB
C
44 lines
1.2 KiB
C
|
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
|
||
|
|
#ifndef _ALPHA_SWAB_H
|
||
|
|
#define _ALPHA_SWAB_H
|
||
|
|
|
||
|
|
#include <linux/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__ */
|
||
|
|
|
||
|
|
#endif /* _ALPHA_SWAB_H */
|