1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 2/*
 3 *  arch/arm/include/asm/byteorder.h
 4 *
 5 * ARM Endian-ness.  In little endian mode, the data bus is connected such
 6 * that byte accesses appear as:
 7 *  0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
 8 * and word accesses (data or instruction) appear as:
 9 *  d0...d31
10 *
11 * When in big endian mode, byte accesses appear as:
12 *  0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
13 * and word accesses (data or instruction) appear as:
14 *  d0...d31
15 */
16#ifndef _UAPI__ASM_ARM_SWAB_H
17#define _UAPI__ASM_ARM_SWAB_H
18
19#include <linux/compiler.h>
20#include <linux/types.h>
21
22#if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
23#  define __SWAB_64_THRU_32__
24#endif
25
26
27#if !defined(__KERNEL__) || __LINUX_ARM_ARCH__ < 6
28static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
29{
30	__u32 t;
31
32#ifndef __thumb__
33	if (!__builtin_constant_p(x)) {
34		/*
35		 * The compiler needs a bit of a hint here to always do the
36		 * right thing and not screw it up to different degrees
37		 * depending on the gcc version.
38		 */
39		asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
40	} else
41#endif
42		t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
43
44	x = (x << 24) | (x >> 8);		/* mov r0,r0,ror #8      */
45	t &= ~0x00FF0000;			/* bic r1,r1,#0x00FF0000 */
46	x ^= (t >> 8);				/* eor r0,r0,r1,lsr #8   */
47
48	return x;
49}
50#define __arch_swab32 __arch_swab32
51
52#endif
53
54#endif /* _UAPI__ASM_ARM_SWAB_H */

 
 1/*
 2 *  arch/arm/include/asm/byteorder.h
 3 *
 4 * ARM Endian-ness.  In little endian mode, the data bus is connected such
 5 * that byte accesses appear as:
 6 *  0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31
 7 * and word accesses (data or instruction) appear as:
 8 *  d0...d31
 9 *
10 * When in big endian mode, byte accesses appear as:
11 *  0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7
12 * and word accesses (data or instruction) appear as:
13 *  d0...d31
14 */
15#ifndef _UAPI__ASM_ARM_SWAB_H
16#define _UAPI__ASM_ARM_SWAB_H
17
18#include <linux/compiler.h>
19#include <linux/types.h>
20
21#if !defined(__STRICT_ANSI__) || defined(__KERNEL__)
22#  define __SWAB_64_THRU_32__
23#endif
24
25
26#if !defined(__KERNEL__) || __LINUX_ARM_ARCH__ < 6
27static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
28{
29	__u32 t;
30
31#ifndef __thumb__
32	if (!__builtin_constant_p(x)) {
33		/*
34		 * The compiler needs a bit of a hint here to always do the
35		 * right thing and not screw it up to different degrees
36		 * depending on the gcc version.
37		 */
38		asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x));
39	} else
40#endif
41		t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */
42
43	x = (x << 24) | (x >> 8);		/* mov r0,r0,ror #8      */
44	t &= ~0x00FF0000;			/* bic r1,r1,#0x00FF0000 */
45	x ^= (t >> 8);				/* eor r0,r0,r1,lsr #8   */
46
47	return x;
48}
49#define __arch_swab32 __arch_swab32
50
51#endif
52
53#endif /* _UAPI__ASM_ARM_SWAB_H */