/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* * arch/arm/include/asm/byteorder.h * * ARM Endian-ness. In little endian mode, the data bus is connected such * that byte accesses appear as: * 0 = d0...d7, 1 = d8...d15, 2 = d16...d23, 3 = d24...d31 * and word accesses (data or instruction) appear as: * d0...d31 * * When in big endian mode, byte accesses appear as: * 0 = d24...d31, 1 = d16...d23, 2 = d8...d15, 3 = d0...d7 * and word accesses (data or instruction) appear as: * d0...d31 */ #ifndef _UAPI__ASM_ARM_SWAB_H #define _UAPI__ASM_ARM_SWAB_H #include <linux/compiler.h> #include <linux/types.h> #if !defined(__STRICT_ANSI__) || defined(__KERNEL__) # define __SWAB_64_THRU_32__ #endif #if !defined(__KERNEL__) || __LINUX_ARM_ARCH__ < 6 static inline __attribute_const__ __u32 __arch_swab32(__u32 x) { __u32 t; #ifndef __thumb__ if (!__builtin_constant_p(x)) { /* * The compiler needs a bit of a hint here to always do the * right thing and not screw it up to different degrees * depending on the gcc version. */ asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); } else #endif t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ return x; } #define __arch_swab32 __arch_swab32 #endif #endif /* _UAPI__ASM_ARM_SWAB_H */