Collect the implementations from include/linux/byteorder/swab.h, swabb.h
in swab.h

The functionality provided covers:
u16 swab16(u16 val) - return a byteswapped 16 bit value
u32 swab32(u32 val) - return a byteswapped 32 bit value
u64 swab64(u64 val) - return a byteswapped 64 bit value
u32 swahw32(u32 val) - return a wordswapped 32 bit value
u32 swahb32(u32 val) - return a high/low byteswapped 32 bit value

The above 5 allow for compiler-time constant folding, and are implemented such
that they can be used in any context (defines, case statements, etc).

Similar to above, but return swapped value from a naturally-aligned pointer
u16 swab16p(u16 *p)
u32 swab32p(u32 *p)
u64 swab64p(u64 *p)
u32 swahw32p(u32 *p)
u32 swahb32p(u32 *p)

Similar to above, but swap the value in-place (in-situ)
void swab16s(u16 *p)
void swab32s(u32 *p)
void swab64s(u64 *p)
void swahw32s(u32 *p)
void swahb32s(u32 *p)

Arches can override any of these with an optimized version by defining an
inline in their asm/byteorder.h (example given for swab16()):

u16 __arch_swab16() {}

Signed-off-by: Harvey Harrison
---
include/linux/swab.h | 309 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 309 insertions(+), 0 deletions(-)

diff --git a/include/linux/swab.h b/include/linux/swab.h
new file mode 100644
index 0000000..8f955b2
--- /dev/null
+++ b/include/linux/swab.h
@@ -0,0 +1,309 @@
+#ifndef _LINUX_SWAB_H
+#define _LINUX_SWAB_H
+
+#include
+#include
+#include
+
+/*
+ * casts are necessary for constants, because we never know how for sure
+ * how U/UL/ULL map to __u16, __u32, __u64. At least not in a portable way.
+ */
+#define __const_swab16(x) ((__u16)( \
+ (((__u16)(x) & (__u16)0x00ffU) << 8) | \
+ (((__u16)(x) & (__u16)0xff00U) >> 8)))
+
+#define __const_swab32(x) ((__u32)( \
+ (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
+ (((__u32)(x) & (__u32)0x0000ff00UL) << 8) | \
+ (((__u32)(x) & (__u32)0x00ff0000UL) >> 8) | \
+ (((__u32)(x) & (__u32)0xff000000UL) >> 24)))
+
+#define __const_swab64(x) ((__u64)( \
+ (((__u64)(x) & (__u64)0x00000000000000ffULL) << 56) | \
+ (((__u64)(x) & (__u64)0x000000000000ff00ULL) << 40) | \
+ (((__u64)(x) & (__u64)0x0000000000ff0000ULL) << 24) | \
+ (((__u64)(x) & (__u64)0x00000000ff000000ULL) << 8) | \
+ (((__u64)(x) & (__u64)0x000000ff00000000ULL) >> 8) | \
+ (((__u64)(x) & (__u64)0x0000ff0000000000ULL) >> 24) | \
+ (((__u64)(x) & (__u64)0x00ff000000000000ULL) >> 40) | \
+ (((__u64)(x) & (__u64)0xff00000000000000ULL) >> 56)))
+
+#define __const_swahw32(x) ((__u32)( \
+ (((__u32)(x) & (__u32)0x0000ffffUL) << 16) | \
+ (((__u32)(x) & (__u32)0xffff0000UL) >> 16)))
+
+#define __const_swahb32(x) ((__u32)( \
+ (((__u32)(x) & (__u32)0x00ff00ffUL) << 8) | \
+ (((__u32)(x) & (__u32)0xff00ff00UL) >> 8)))
+
+/*
+ * Implement the following as inlines, but define the interface using
+ * macros to allow constant folding when possible:
+ * ___swab16, ___swab32, ___swab64, ___swahw32, ___swahb32
+ */
+
+static inline __attribute_const__ __u16 ___swab16(__u16 val)
+{
+#ifdef HAVE_ARCH_SWAB16
+ return __arch_swab16(val);
+#elif defined(HAVE_ARCH_SWAB16P)
+ return __arch_swab16p(&val);
+#else
+ return __const_swab16(val);
+#endif
+}
+
+static inline __attribute_const__ __u32 ___swab32(__u32 val)
+{
+#ifdef HAVE_ARCH_SWAB32
+ return __arch_swab32(val);
+#elif defined(HAVE_ARCH_SWAB32P)
+ return __arch_swab32p(&val);
+#else
+ return __const_swab32(val);
+#endif
+}
+
+static inline __attribute_const__ __u64 ___swab64(__u64 val)
+{
+#ifdef HAVE_ARCH_SWAB64
+ return __arch_swab64(val);
+#elif defined(HAVE_ARCH_SWAB64P)
+ return __arch_swab64p(&val);
+#elif defined(__SWAB_64_THRU_32__)
+ __u32 h = val >> 32;
+ __u32 l = val & ((1ULL << 32) - 1);
+ return (((__u64)___swab32(l)) << 32) | ((__u64)(___swab32(h)));
+#else
+ return __const_swab64(val);
+#endif
+}
+
+static inline __attribute_const__ __u32 ___swahw32(__u32 val)
+{
+#ifdef HAVE_ARCH_SWAHW32
+ return __arch_swahw32(val);
+#elif defined(HAVE_ARCH_SWAHW32P)
+ return __arch_swahw32p(&val);
+#else
+ return __const_swahw32(val);
+#endif
+}
+
+static inline __attribute_const__ __u32 ___swahb32(__u32 val)
+{
+#ifdef HAVE_ARCH_SWAHB32
+ return __arch_swahb32(val);
+#elif defined(HAVE_ARCH_SWAHB32P)
+ return __arch_swahb32p(&val);
+#else
+ return __const_swahb32(val);
+#endif
+}
+
+/**
+ * __swab16 - return a byteswapped 16-bit value
+ * @x: value to byteswap
+ */
+#define __swab16(x) \
+ (__builtin_constant_p((__u16)(x)) ? \
+ __const_swab16((x)) : \
+ ___swab16((x)))
+
+/**
+ * __swab32 - return a byteswapped 32-bit value
+ * @x: value to byteswap
+ */
+#define __swab32(x) \
+ (__builtin_constant_p((__u32)(x)) ? \
+ __const_swab32((x)) : \
+ ___swab32((x)))
+
+/**
+ * __swab64 - return a byteswapped 64-bit value
+ * @x: value to byteswap
+ */
+#define __swab64(x) \
+ (__builtin_constant_p((__u64)(x)) ? \
+ __const_swab64((x)) : \
+ ___swab64((x)))
+
+/**
+ * __swahw32 - return a word-swapped 32-bit value
+ * @x: value to wordswap
+ *
+ * __swahw32(0x12340000) is 0x00001234
+ */
+#define __swahw32(x) \
+ (__builtin_constant_p((__u32)(x)) ? \
+ __const_swahw32((x)) : \
+ ___swahw32((x)))
+
+/**
+ * __swahb32 - return a high and low byte-swapped 32-bit value
+ * @x: value to byteswap
+ *
+ * __swahb32(0x12345678) is 0x34127856
+ */
+#define __swahb32(x) \
+ (__builtin_constant_p((__u32)(x)) ? \
+ __const_swahb32((x)) : \
+ ___swahb32((x)))
+
+/**
+ * __swab16p - return a byteswapped 16-bit value from a pointer
+ * @p: pointer to a naturally-aligned 16-bit value
+ */
+static inline __u16 __swab16p(const __u16 *p)
+{
+#ifdef HAVE_ARCH_SWAB16P
+ return __arch_swab16p(p);
+#else
+ return __swab16(*p);
+#endif
+}
+
+/**
+ * __swab32p - return a byteswapped 32-bit value from a pointer
+ * @p: pointer to a naturally-aligned 32-bit value
+ */
+static inline __u32 __swab32p(const __u32 *p)
+{
+#ifdef HAVE_ARCH_SWAB32P
+ return __arch_swab32p(p);
+#else
+ return __swab32(*p);
+#endif
+}
+
+/**
+ * __swab64p - return a byteswapped 64-bit value from a pointer
+ * @p: pointer to a naturally-aligned 64-bit value
+ */
+static inline __u64 __swab64p(const __u64 *p)
+{
+#ifdef HAVE_ARCH_SWAB64P
+ return __arch_swab64p(p);
+#else
+ return __swab64(*p);
+#endif
+}
+
+/**
+ * __swahw32p - return a wordswapped 32-bit value from a pointer
+ * @p: pointer to a naturally-aligned 32-bit value
+ *
+ * See __swahw32() for details of wordswapping.
+ */
+static inline __u32 __swahw32p(const __u32 *p)
+{
+#ifdef HAVE_ARCH_SWAHW32P
+ return __arch_swahw32p(p);
+#else
+ return __swahw32(*p);
+#endif
+}
+
+/**
+ * __swahb32p - return a high and low byteswapped 32-bit value from a pointer
+ * @p: pointer to a naturally-aligned 32-bit value
+ *
+ * See __swahb32() for details of high/low byteswapping.
+ */
+static inline __u32 __swahb32p(const __u32 *p)
+{
+#ifdef HAVE_ARCH_SWAHB32P
+ return __arch_swahb32p(p);
+#else
+ return __swahb32(*p);
+#endif
+}
+
+/**
+ * __swab16s - byteswap a 16-bit value in-place
+ * @p: pointer to a naturally-aligned 16-bit value
+ */
+static inline void __swab16s(__u16 *p)
+{
+#ifdef HAVE_ARCH_SWAB16S
+ __arch_swab16s(p);
+#else
+ *p = __swab16p(p);
+#endif
+}
+/**
+ * __swab32s - byteswap a 32-bit value in-place
+ * @p: pointer to a naturally-aligned 32-bit value
+ */
+static inline void __swab32s(__u32 *p)
+{
+#ifdef HAVE_ARCH_SWAB32S
+ __arch_swab32s(p);
+#else
+ *p = __swab32p(p);
+#endif
+}
+
+/**
+ * __swab64s - byteswap a 64-bit value in-place
+ * @p: pointer to a naturally-aligned 64-bit value
+ */
+static inline void __swab64s(__u64 *p)
+{
+#ifdef HAVE_ARCH_SWAB64S
+ __arch_swab64s(p);
+#else
+ *p = __swab64p(p);
+#endif
+}
+
+/**
+ * __swahw32s - wordswap a 32-bit value in-place
+ * @p: pointer to a naturally-aligned 32-bit value
+ *
+ * See __swahw32() for details of wordswapping
+ */
+static inline void __swahw32s(__u32 *p)
+{
+#ifdef HAVE_ARCH_SWAHW32S
+ __arch_swahw32s(p);
+#else
+ *p = __swahw32p(p);
+#endif
+}
+
+/**
+ * __swahb32s - high and low byteswap a 32-bit value in-place
+ * @p: pointer to a naturally-aligned 32-bit value
+ *
+ * See __swahb32() for details of high and low byte swapping
+ */
+static inline void __swahb32s(__u32 *p)
+{
+#ifdef HAVE_ARCH_SWAHB32S
+ __arch_swahb32s(p);
+#else
+ *p = __swahb32p(p);
+#endif
+}
+
+#ifdef __KERNEL__
+# define swab16 __swab16
+# define swab32 __swab32
+# define swab64 __swab64
+# define swahw32 __swahw32
+# define swahb32 __swahb32
+# define swab16p __swab16p
+# define swab32p __swab32p
+# define swab64p __swab64p
+# define swahw32p __swahw32p
+# define swahb32p __swahb32p
+# define swab16s __swab16s
+# define swab32s __swab32s
+# define swab64s __swab64s
+# define swahw32s __swahw32s
+# define swahb32s __swahb32s
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_SWAB_H */
--
1.5.6.1.281.g1087e


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