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