ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction
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>
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index 7ffe03f..fb790b8 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -3,14 +3,83 @@
#include <linux/types.h>
-extern u8 const byte_rev_table[256];
+#ifdef CONFIG_HAVE_ARCH_BITREVERSE
+#include <asm/bitrev.h>
-static inline u8 bitrev8(u8 byte)
+#define __bitrev32 __arch_bitrev32
+#define __bitrev16 __arch_bitrev16
+#define __bitrev8 __arch_bitrev8
+
+#else
+extern u8 const byte_rev_table[256];
+static inline u8 __bitrev8(u8 byte)
{
return byte_rev_table[byte];
}
-extern u16 bitrev16(u16 in);
-extern 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 __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_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 bitrev8(x) \
+({ \
+ u8 __x = x; \
+ __builtin_constant_p(__x) ? \
+ __constant_bitrev8(__x) : \
+ __bitrev8(__x) ; \
+ })
#endif /* _LINUX_BITREV_H */