Add Linux-compatible rol32/ror32 functions. Amazingly, gcc will

optimise these down to the correct single "roll"/"rorl" instruction.

src/include/gpxe/bitops.h

@@ -0,0 +1,19 @@
+#ifndef _GPXE_BITOPS_H
+#define _GPXE_BITOPS_H
+
+/** @file
+ *
+ * Bit operations
+ */
+
+#include <stdint.h>
+
+static inline uint32_t rol32 ( uint32_t data, unsigned int rotation ) {
+        return ( ( data << rotation ) | ( data >> ( 32 - rotation ) ) );
+}
+
+static inline uint32_t ror32 ( uint32_t data, unsigned int rotation ) {
+        return ( ( data >> rotation ) | ( data << ( 32 - rotation ) ) );
+}
+
+#endif /* _GPXE_BITOPS_H */