summaryrefslogtreecommitdiffstats
path: root/include/linux/bitrev.h
diff options
context:
space:
mode:
authorJoshua Clayton <stillcompiling@gmail.com>2017-06-14 10:36:31 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-07-17 17:26:14 +0200
commit3b88da4aba2549497ac8868877562f1b1913ca62 (patch)
tree71ab6007d676f87e817333e560cfaa8a7b1df671 /include/linux/bitrev.h
parent60acfa593731f496a9f258d2e118297ef956d98d (diff)
downloadop-kernel-dev-3b88da4aba2549497ac8868877562f1b1913ca62.zip
op-kernel-dev-3b88da4aba2549497ac8868877562f1b1913ca62.tar.gz
lib: add bitrev8x4()
Add a function to reverse bytes within a 32 bit word. Operate on a u32 rather than individual bytes. Signed-off-by: Joshua Clayton <stillcompiling@gmail.com> Signed-off-by: Alan Tull <atull@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/bitrev.h')
-rw-r--r--include/linux/bitrev.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/bitrev.h b/include/linux/bitrev.h
index fb790b8..b97be27 100644
--- a/include/linux/bitrev.h
+++ b/include/linux/bitrev.h
@@ -29,6 +29,8 @@ static inline u32 __bitrev32(u32 x)
#endif /* CONFIG_HAVE_ARCH_BITREVERSE */
+#define __bitrev8x4(x) (__bitrev32(swab32(x)))
+
#define __constant_bitrev32(x) \
({ \
u32 __x = x; \
@@ -50,6 +52,15 @@ static inline u32 __bitrev32(u32 x)
__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; \
@@ -75,6 +86,14 @@ static inline u32 __bitrev32(u32 x)
__bitrev16(__x); \
})
+#define bitrev8x4(x) \
+({ \
+ u32 __x = x; \
+ __builtin_constant_p(__x) ? \
+ __constant_bitrev8x4(__x) : \
+ __bitrev8x4(__x); \
+ })
+
#define bitrev8(x) \
({ \
u8 __x = x; \
OpenPOWER on IntegriCloud