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authorRichard Henderson <rth@twiddle.net>2015-09-14 13:00:34 -0700
committerRichard Henderson <rth@twiddle.net>2015-09-15 07:45:33 -0700
commit652a4b7e736f432a6809d1d2b52d169ab0b9aa3b (patch)
treee8390db3048941d4f714ea025511facf7cc20d0d /include/qemu
parent89b8c7504fbc53a35c76e7738dbdf53f3c254b8f (diff)
downloadhqemu-652a4b7e736f432a6809d1d2b52d169ab0b9aa3b.zip
hqemu-652a4b7e736f432a6809d1d2b52d169ab0b9aa3b.tar.gz
host-utils: Add revbit functions
Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'include/qemu')
-rw-r--r--include/qemu/host-utils.h77
1 files changed, 77 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index 7d36ebf..3ef97d5 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -26,6 +26,7 @@
#define HOST_UTILS_H 1
#include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */
+#include "qemu/bswap.h"
#include <limits.h>
#include <stdbool.h>
@@ -391,6 +392,80 @@ static inline int ctpop64(uint64_t val)
#endif
}
+/**
+ * revbit8 - reverse the bits in an 8-bit value.
+ * @x: The value to modify.
+ */
+static inline uint8_t revbit8(uint8_t x)
+{
+ /* Assign the correct nibble position. */
+ x = ((x & 0xf0) >> 4)
+ | ((x & 0x0f) << 4);
+ /* Assign the correct bit position. */
+ x = ((x & 0x88) >> 3)
+ | ((x & 0x44) >> 1)
+ | ((x & 0x22) << 1)
+ | ((x & 0x11) << 3);
+ return x;
+}
+
+/**
+ * revbit16 - reverse the bits in a 16-bit value.
+ * @x: The value to modify.
+ */
+static inline uint16_t revbit16(uint16_t x)
+{
+ /* Assign the correct byte position. */
+ x = bswap16(x);
+ /* Assign the correct nibble position. */
+ x = ((x & 0xf0f0) >> 4)
+ | ((x & 0x0f0f) << 4);
+ /* Assign the correct bit position. */
+ x = ((x & 0x8888) >> 3)
+ | ((x & 0x4444) >> 1)
+ | ((x & 0x2222) << 1)
+ | ((x & 0x1111) << 3);
+ return x;
+}
+
+/**
+ * revbit32 - reverse the bits in a 32-bit value.
+ * @x: The value to modify.
+ */
+static inline uint32_t revbit32(uint32_t x)
+{
+ /* Assign the correct byte position. */
+ x = bswap32(x);
+ /* Assign the correct nibble position. */
+ x = ((x & 0xf0f0f0f0u) >> 4)
+ | ((x & 0x0f0f0f0fu) << 4);
+ /* Assign the correct bit position. */
+ x = ((x & 0x88888888u) >> 3)
+ | ((x & 0x44444444u) >> 1)
+ | ((x & 0x22222222u) << 1)
+ | ((x & 0x11111111u) << 3);
+ return x;
+}
+
+/**
+ * revbit64 - reverse the bits in a 64-bit value.
+ * @x: The value to modify.
+ */
+static inline uint64_t revbit64(uint64_t x)
+{
+ /* Assign the correct byte position. */
+ x = bswap64(x);
+ /* Assign the correct nibble position. */
+ x = ((x & 0xf0f0f0f0f0f0f0f0ull) >> 4)
+ | ((x & 0x0f0f0f0f0f0f0f0full) << 4);
+ /* Assign the correct bit position. */
+ x = ((x & 0x8888888888888888ull) >> 3)
+ | ((x & 0x4444444444444444ull) >> 1)
+ | ((x & 0x2222222222222222ull) << 1)
+ | ((x & 0x1111111111111111ull) << 3);
+ return x;
+}
+
/* Host type specific sizes of these routines. */
#if ULONG_MAX == UINT32_MAX
@@ -399,12 +474,14 @@ static inline int ctpop64(uint64_t val)
# define clol clo32
# define ctol cto32
# define ctpopl ctpop32
+# define revbitl revbit32
#elif ULONG_MAX == UINT64_MAX
# define clzl clz64
# define ctzl ctz64
# define clol clo64
# define ctol cto64
# define ctpopl ctpop64
+# define revbitl revbit64
#else
# error Unknown sizeof long
#endif
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