Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
Russell King | 4baa992 | 2008-08-02 10:55:55 +0100 | [diff] [blame] | 2 | * arch/arm/include/asm/byteorder.h |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 __ASM_ARM_BYTEORDER_H |
| 16 | #define __ASM_ARM_BYTEORDER_H |
| 17 | |
Russell King | fe5dd7c | 2006-01-07 16:55:50 +0000 | [diff] [blame] | 18 | #include <linux/compiler.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | #include <asm/types.h> |
| 20 | |
Andre McCurdy | 6351610 | 2006-01-07 11:39:20 +0000 | [diff] [blame] | 21 | static inline __attribute_const__ __u32 ___arch__swab32(__u32 x) |
| 22 | { |
| 23 | __u32 t; |
| 24 | |
H. Peter Anvin | 441ff85 | 2006-06-19 15:35:36 +0100 | [diff] [blame] | 25 | #ifndef __thumb__ |
| 26 | if (!__builtin_constant_p(x)) { |
Nicolas Pitre | a3e4943 | 2006-01-10 19:48:02 +0000 | [diff] [blame] | 27 | /* |
| 28 | * The compiler needs a bit of a hint here to always do the |
| 29 | * right thing and not screw it up to different degrees |
| 30 | * depending on the gcc version. |
| 31 | */ |
| 32 | asm ("eor\t%0, %1, %1, ror #16" : "=r" (t) : "r" (x)); |
H. Peter Anvin | 441ff85 | 2006-06-19 15:35:36 +0100 | [diff] [blame] | 33 | } else |
| 34 | #endif |
| 35 | t = x ^ ((x << 16) | (x >> 16)); /* eor r1,r0,r0,ror #16 */ |
| 36 | |
Andre McCurdy | 6351610 | 2006-01-07 11:39:20 +0000 | [diff] [blame] | 37 | x = (x << 24) | (x >> 8); /* mov r0,r0,ror #8 */ |
| 38 | t &= ~0x00FF0000; /* bic r1,r1,#0x00FF0000 */ |
| 39 | x ^= (t >> 8); /* eor r0,r0,r1,lsr #8 */ |
| 40 | |
| 41 | return x; |
| 42 | } |
| 43 | |
| 44 | #define __arch__swab32(x) ___arch__swab32(x) |
| 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | #if !defined(__STRICT_ANSI__) || defined(__KERNEL__) |
| 47 | # define __BYTEORDER_HAS_U64__ |
| 48 | # define __SWAB_64_THRU_32__ |
| 49 | #endif |
| 50 | |
| 51 | #ifdef __ARMEB__ |
| 52 | #include <linux/byteorder/big_endian.h> |
| 53 | #else |
| 54 | #include <linux/byteorder/little_endian.h> |
| 55 | #endif |
| 56 | |
| 57 | #endif |
| 58 | |