byteswap.h: Import from musl

Copied as is from the official musl git mirror
git://git.musl-libc.org/musl, commit 6fcb440d.

Signed-off-by: Vlad-Andrei BĂDOIU <vlad_andrei.badoiu@stud.acs.upb.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

diff --git a/musl-imported/include/byteswap.h b/musl-imported/include/byteswap.h
new file mode 100644 (file)
index 0000000..00b9df3
--- /dev/null
+++ b/musl-imported/include/byteswap.h
@@ -0,0 +1,26 @@
+#ifndef _BYTESWAP_H
+#define _BYTESWAP_H
+
+#include <features.h>
+#include <stdint.h>
+
+static __inline uint16_t __bswap_16(uint16_t __x)
+{
+       return __x<<8 | __x>>8;
+}
+
+static __inline uint32_t __bswap_32(uint32_t __x)
+{
+       return __x>>24 | __x>>8&0xff00 | __x<<8&0xff0000 | __x<<24;
+}
+
+static __inline uint64_t __bswap_64(uint64_t __x)
+{
+       return __bswap_32(__x)+0ULL<<32 | __bswap_32(__x>>32);
+}
+
+#define bswap_16(x) __bswap_16(x)
+#define bswap_32(x) __bswap_32(x)
+#define bswap_64(x) __bswap_64(x)
+
+#endif