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![Yalin Wang](/assets/img/avatar_default.png)
this change add CONFIG_HAVE_ARCH_BITREVERSE config option, so that we can use some architecture's bitrev hardware instruction to do bitrev operation. Introduce __constant_bitrev* macro for constant bitrev operation. Change __bitrev16() __bitrev32() to be inline function, don't need export symbol for these tiny functions. Signed-off-by: Yalin Wang <yalin.wang@sonymobile.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
85 lines
2 KiB
C
85 lines
2 KiB
C
#ifndef _LINUX_BITREV_H
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#define _LINUX_BITREV_H
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#include <linux/types.h>
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#ifdef CONFIG_HAVE_ARCH_BITREVERSE
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#include <asm/bitrev.h>
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#define __bitrev32 __arch_bitrev32
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#define __bitrev16 __arch_bitrev16
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#define __bitrev8 __arch_bitrev8
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#else
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extern u8 const byte_rev_table[256];
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static inline u8 __bitrev8(u8 byte)
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{
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return byte_rev_table[byte];
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}
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static inline u16 __bitrev16(u16 x)
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{
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return (__bitrev8(x & 0xff) << 8) | __bitrev8(x >> 8);
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}
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static inline u32 __bitrev32(u32 x)
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{
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return (__bitrev16(x & 0xffff) << 16) | __bitrev16(x >> 16);
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}
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#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
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#define __constant_bitrev32(x) \
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({ \
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u32 __x = x; \
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__x = (__x >> 16) | (__x << 16); \
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__x = ((__x & (u32)0xFF00FF00UL) >> 8) | ((__x & (u32)0x00FF00FFUL) << 8); \
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__x = ((__x & (u32)0xF0F0F0F0UL) >> 4) | ((__x & (u32)0x0F0F0F0FUL) << 4); \
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__x = ((__x & (u32)0xCCCCCCCCUL) >> 2) | ((__x & (u32)0x33333333UL) << 2); \
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__x = ((__x & (u32)0xAAAAAAAAUL) >> 1) | ((__x & (u32)0x55555555UL) << 1); \
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__x; \
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})
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#define __constant_bitrev16(x) \
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({ \
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u16 __x = x; \
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__x = (__x >> 8) | (__x << 8); \
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__x = ((__x & (u16)0xF0F0U) >> 4) | ((__x & (u16)0x0F0FU) << 4); \
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__x = ((__x & (u16)0xCCCCU) >> 2) | ((__x & (u16)0x3333U) << 2); \
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__x = ((__x & (u16)0xAAAAU) >> 1) | ((__x & (u16)0x5555U) << 1); \
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__x; \
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})
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#define __constant_bitrev8(x) \
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({ \
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u8 __x = x; \
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__x = (__x >> 4) | (__x << 4); \
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__x = ((__x & (u8)0xCCU) >> 2) | ((__x & (u8)0x33U) << 2); \
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__x = ((__x & (u8)0xAAU) >> 1) | ((__x & (u8)0x55U) << 1); \
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__x; \
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})
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#define bitrev32(x) \
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({ \
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u32 __x = x; \
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__builtin_constant_p(__x) ? \
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__constant_bitrev32(__x) : \
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__bitrev32(__x); \
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})
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#define bitrev16(x) \
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({ \
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u16 __x = x; \
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__builtin_constant_p(__x) ? \
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__constant_bitrev16(__x) : \
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__bitrev16(__x); \
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})
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#define bitrev8(x) \
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({ \
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u8 __x = x; \
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__builtin_constant_p(__x) ? \
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__constant_bitrev8(__x) : \
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__bitrev8(__x) ; \
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})
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#endif /* _LINUX_BITREV_H */
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