-/*(C) Timothy B. Terriberry (tterribe@xiph.org) 2001-2009 LGPL (v2 or later).*/
+/*(C) Timothy B. Terriberry (tterribe@xiph.org) 2001-2009 CC0 (Public domain).
+ * See LICENSE file for details. */
#include "ilog.h"
#include <limits.h>
year=1998,
note="\url{http://supertech.csail.mit.edu/papers/debruijn.pdf}"
}*/
-#if !defined(ILOG_NODEBRUIJN)&& \
- !defined(CLZ32)||!defined(CLZ64)&&LONG_MAX<9223372036854775807LL
-static const unsigned char DEBRUIJN_IDX32[32]={
+static UNNEEDED const unsigned char DEBRUIJN_IDX32[32]={
0, 1,28, 2,29,14,24, 3,30,22,20,15,25,17, 4, 8,
31,27,13,23,21,19,16, 7,26,12,18, 6,11, 5,10, 9
};
-#endif
+
+/* We always compile these in, in case someone takes address of function. */
+#undef ilog32_nz
+#undef ilog32
+#undef ilog64_nz
+#undef ilog64
int ilog32(uint32_t _v){
-#if defined(CLZ32)
- return (CLZ32_OFFS-CLZ32(_v))&-!!_v;
-#else
/*On a Pentium M, this branchless version tested as the fastest version without
multiplications on 1,000,000,000 random 32-bit integers, edging out a
similar version with branches, and a 256-entry LUT version.*/
ret+=DEBRUIJN_IDX32[_v*0x77CB531U>>27&0x1F];
return ret;
# endif
-#endif
+}
+
+int ilog32_nz(uint32_t _v)
+{
+ return ilog32(_v);
}
int ilog64(uint64_t _v){
-#if defined(CLZ64)
- return (CLZ64_OFFS-CLZ64(_v))&-!!_v;
-#else
# if defined(ILOG_NODEBRUIJN)
uint32_t v;
int ret;
return ret;
# endif
# endif
-#endif
}
+
+int ilog64_nz(uint64_t _v)
+{
+ return ilog64(_v);
+}
+