1 /* SPDX-License-Identifier: GPL-2.0 */
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 __ASM_ARM_SWAB_H
17 #define __ASM_ARM_SWAB_H
18
19 #include <uapi/asm/swab.h>
20
21 #if __LINUX_ARM_ARCH__ >= 6
22
23 static inline __attribute_const__ __u32 __arch_swahb32(__u32 x)
24 {
25 __asm__ ("rev16 %0, %1" : "=r" (x) : "r" (x));
26 return x;
27 }
28 #define __arch_swahb32 __arch_swahb32
29 #define __arch_swab16(x) ((__u16)__arch_swahb32(x))
30
31 static inline __attribute_const__ __u32 __arch_swab32(__u32 x)
32 {
33 __asm__ ("rev %0, %1" : "=r" (x) : "r" (x));
34 return x;
35 }
36 #define __arch_swab32 __arch_swab32
37
38 #endif
39 #endif
40
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