x86: introduce asm/swab.h

[mirror_ubuntu-artful-kernel.git] / arch / x86 / include / asm / swab.h

diff --git a/arch/x86/include/asm/swab.h b/arch/x86/include/asm/swab.h
new file mode 100644 (file)
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 */