1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _ALPHA_SWAB_H
3#define _ALPHA_SWAB_H
4
5#include <linux/types.h>
6#include <linux/compiler.h>
7#include <asm/compiler.h>
8
9#ifdef __GNUC__
10
11static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
12{
13	/*
14	 * Unfortunately, we can't use the 6 instruction sequence
15	 * on ev6 since the latency of the UNPKBW is 3, which is
16	 * pretty hard to hide.  Just in case a future implementation
17	 * has a lower latency, here's the sequence (also by Mike Burrows)
18	 *
19	 * UNPKBW a0, v0       v0: 00AA00BB00CC00DD
20	 * SLL v0, 24, a0      a0: BB00CC00DD000000
21	 * BIS v0, a0, a0      a0: BBAACCBBDDCC00DD
22	 * EXTWL a0, 6, v0     v0: 000000000000BBAA
23	 * ZAP a0, 0xf3, a0    a0: 00000000DDCC0000
24	 * ADDL a0, v0, v0     v0: ssssssssDDCCBBAA
25	 */
26
27	__u64 t0, t1, t2, t3;
28
29	t0 = __kernel_inslh(x, 7);	/* t0 : 0000000000AABBCC */
30	t1 = __kernel_inswl(x, 3);	/* t1 : 000000CCDD000000 */
31	t1 |= t0;			/* t1 : 000000CCDDAABBCC */
32	t2 = t1 >> 16;			/* t2 : 0000000000CCDDAA */
33	t0 = t1 & 0xFF00FF00;		/* t0 : 00000000DD00BB00 */
34	t3 = t2 & 0x00FF00FF;		/* t3 : 0000000000CC00AA */
35	t1 = t0 + t3;			/* t1 : ssssssssDDCCBBAA */
36
37	return t1;
38}
39#define __arch_swab32 __arch_swab32
40
41#endif /* __GNUC__ */
42
43#endif /* _ALPHA_SWAB_H */
44