x86: introduce asm/swab.h
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/include/asm/swab.h b/arch/x86/include/asm/swab.h
new file mode 100644
index 0000000..306d417
--- /dev/null
+++ b/arch/x86/include/asm/swab.h
@@ -0,0 +1,61 @@
+#ifndef _ASM_X86_SWAB_H
+#define _ASM_X86_SWAB_H
+
+#include <asm/types.h>
+#include <linux/compiler.h>
+
+static inline __attribute_const__ __u32 __arch_swab32(__u32 val)
+{
+#ifdef __i386__
+# ifdef CONFIG_X86_BSWAP
+ asm("bswap %0" : "=r" (val) : "0" (val));
+# else
+ asm("xchgb %b0,%h0\n\t" /* swap lower bytes */
+ "rorl $16,%0\n\t" /* swap words */
+ "xchgb %b0,%h0" /* swap higher bytes */
+ : "=q" (val)
+ : "0" (val));
+# endif
+
+#else /* __i386__ */
+ asm("bswapl %0"
+ : "=r" (val)
+ : "0" (val));
+#endif
+ return val;
+}
+#define __arch_swab32 __arch_swab32
+
+static inline __attribute_const__ __u64 __arch_swab64(__u64 val)
+{
+#ifdef __i386__
+ union {
+ struct {
+ __u32 a;
+ __u32 b;
+ } s;
+ __u64 u;
+ } v;
+ v.u = val;
+# ifdef CONFIG_X86_BSWAP
+ asm("bswapl %0 ; bswapl %1 ; xchgl %0,%1"
+ : "=r" (v.s.a), "=r" (v.s.b)
+ : "0" (v.s.a), "1" (v.s.b));
+# else
+ v.s.a = __arch_swab32(v.s.a);
+ v.s.b = __arch_swab32(v.s.b);
+ asm("xchgl %0,%1"
+ : "=r" (v.s.a), "=r" (v.s.b)
+ : "0" (v.s.a), "1" (v.s.b));
+# endif
+ return v.u;
+#else /* __i386__ */
+ asm("bswapq %0"
+ : "=r" (val)
+ : "0" (val));
+ return val;
+#endif
+}
+#define __arch_swab64 __arch_swab64
+
+#endif /* _ASM_X86_SWAB_H */