Signed-off-by: Bin Meng bmeng.cn@gmail.com ---
include/linux/bitrev.h | 102 ++++++++++++++++++++++++++++++++++++++++++++----- lib/bitrev.c | 28 ++++---------- 2 files changed, 101 insertions(+), 29 deletions(-)
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h index cc5abd7..50fb0de 100644 --- a/include/linux/bitrev.h +++ b/include/linux/bitrev.h @@ -1,21 +1,105 @@ -/* SPDX-License-Identifier: GPL-2.0+ */ -/* - * Based on bitrev from the Linux kernel, by Akinobu Mita - */ - +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_BITREV_H #define _LINUX_BITREV_H
#include <linux/types.h>
-extern u8 const byte_rev_table[256]; +#ifdef CONFIG_HAVE_ARCH_BITREVERSE +#include <asm/bitrev.h> + +#define __bitrev32 __arch_bitrev32 +#define __bitrev16 __arch_bitrev16 +#define __bitrev8 __arch_bitrev8
-static inline u8 bitrev8(u8 byte) +#else +extern u8 const byte_rev_table[256]; +static inline u8 __bitrev8(u8 byte) { return byte_rev_table[byte]; }
-u16 bitrev16(u16 in); -u32 bitrev32(u32 in); +static inline u16 __bitrev16(u16 x) +{ + return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8); +} + +static inline u32 __bitrev32(u32 x) +{ + return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16); +} + +#endif /* CONFIG_HAVE_ARCH_BITREVERSE */ + +#define __bitrev8x4(x) (__bitrev32(swab32(x))) + +#define __constant_bitrev32(x) \ +({ \ + u32 __x = x; \ + __x = (__x >> 16) | (__x << 16); \ + __x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8); \ + __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4); \ + __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2); \ + __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1); \ + __x; \ +}) + +#define __constant_bitrev16(x) \ +({ \ + u16 __x = x; \ + __x = (__x >> 8) | (__x << 8); \ + __x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4); \ + __x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2); \ + __x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1); \ + __x; \ +}) + +#define __constant_bitrev8x4(x) \ +({ \ + u32 __x = x; \ + __x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4); \ + __x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2); \ + __x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1); \ + __x; \ +}) + +#define __constant_bitrev8(x) \ +({ \ + u8 __x = x; \ + __x = (__x >> 4) | (__x << 4); \ + __x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2); \ + __x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1); \ + __x; \ +}) + +#define bitrev32(x) \ +({ \ + u32 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev32(__x) : \ + __bitrev32(__x); \ +}) + +#define bitrev16(x) \ +({ \ + u16 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev16(__x) : \ + __bitrev16(__x); \ + }) + +#define bitrev8x4(x) \ +({ \ + u32 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev8x4(__x) : \ + __bitrev8x4(__x); \ + })
+#define bitrev8(x) \ +({ \ + u8 __x = x; \ + __builtin_constant_p(__x) ? \ + __constant_bitrev8(__x) : \ + __bitrev8(__x) ; \ + }) #endif /* _LINUX_BITREV_H */ diff --git a/lib/bitrev.c b/lib/bitrev.c index 4d494e1..beef6c8 100644 --- a/lib/bitrev.c +++ b/lib/bitrev.c @@ -1,13 +1,12 @@ -// SPDX-License-Identifier: GPL-2.0+ -/* - * - * Based on bitrev from the Linux kernel, by Akinobu Mita - */ - - +#ifndef CONFIG_HAVE_ARCH_BITREVERSE #include <linux/types.h> +#include <linux/compat.h> #include <linux/bitrev.h>
+MODULE_AUTHOR("Akinobu Mita akinobu.mita@gmail.com"); +MODULE_DESCRIPTION("Bit ordering reversal functions"); +MODULE_LICENSE("GPL"); + const u8 byte_rev_table[256] = { 0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0, @@ -42,17 +41,6 @@ const u8 byte_rev_table[256] = { 0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff, }; +EXPORT_SYMBOL_GPL(byte_rev_table);
-u16 bitrev16(u16 x) -{ - return (bitrev8(x & 0xff) << 8) | bitrev8(x >> 8); -} - -/** - * bitrev32 - reverse the order of bits in a u32 value - * @x: value to be bit-reversed - */ -u32 bitrev32(u32 x) -{ - return (bitrev16(x & 0xffff) << 16) | bitrev16(x >> 16); -} +#endif /* CONFIG_HAVE_ARCH_BITREVERSE */