X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Falloc%2Fbitops.c;h=78c2b24f4f14f13287ef77445fdc448e535b7bda;hp=ad4465f93b746555d543c5d83b4e32684d242b62;hb=9e002ad08415a415d96555b00242398ab5d16e8b;hpb=7f9d956574d30f70d2260f4b7694f481e3765173

diff --git a/ccan/alloc/bitops.c b/ccan/alloc/bitops.c
index ad4465f9..78c2b24f 100644
--- a/ccan/alloc/bitops.c
+++ b/ccan/alloc/bitops.c
@@ -1,44 +1,22 @@
+/* Licensed under LGPLv2.1+ - see LICENSE file for details */
 #include "bitops.h"
 #include "config.h"
+#include <ccan/build_assert/build_assert.h>
 #include <ccan/short_types/short_types.h>
+#include <ccan/ilog/ilog.h>
 #include <limits.h>
 
-unsigned int fls(unsigned long val)
+unsigned int afls(unsigned long val)
 {
-#if HAVE_BUILTIN_CLZL
-	/* This is significantly faster! */
-	return val ? sizeof(long) * CHAR_BIT - __builtin_clzl(val) : 0;
-#else
-	unsigned int r = 32;
-
-	if (!val)
-		return 0;
-	if (!(val & 0xffff0000u)) {
-		val <<= 16;
-		r -= 16;
-	}
-	if (!(val & 0xff000000u)) {
-		val <<= 8;
-		r -= 8;
-	}
-	if (!(val & 0xf0000000u)) {
-		val <<= 4;
-		r -= 4;
-	}
-	if (!(val & 0xc0000000u)) {
-		val <<= 2;
-		r -= 2;
-	}
-	if (!(val & 0x80000000u)) {
-		val <<= 1;
-		r -= 1;
-	}
-	return r;
-#endif
+	BUILD_ASSERT(sizeof(val) == sizeof(u32) || sizeof(val) == sizeof(u64));
+	if (sizeof(val) == sizeof(u32))
+		return ilog32(val);
+	else
+		return ilog64(val);
 }
 
 /* FIXME: Move to bitops. */
-unsigned int ffsl(unsigned long val)
+unsigned int affsl(unsigned long val)
 {
 #if HAVE_BUILTIN_FFSL
 	/* This is significantly faster! */
@@ -92,22 +70,22 @@ unsigned int popcount(unsigned long val)
 		v = (v & 0x5555555555555555ULL)
 			+ ((v >> 1) & 0x5555555555555555ULL);
 		v = (v & 0x3333333333333333ULL)
-			+ ((v >> 1) & 0x3333333333333333ULL);
+			+ ((v >> 2) & 0x3333333333333333ULL);
 		v = (v & 0x0F0F0F0F0F0F0F0FULL)
-			+ ((v >> 1) & 0x0F0F0F0F0F0F0F0FULL);
+			+ ((v >> 4) & 0x0F0F0F0F0F0F0F0FULL);
 		v = (v & 0x00FF00FF00FF00FFULL)
-			+ ((v >> 1) & 0x00FF00FF00FF00FFULL);
+			+ ((v >> 8) & 0x00FF00FF00FF00FFULL);
 		v = (v & 0x0000FFFF0000FFFFULL)
-			+ ((v >> 1) & 0x0000FFFF0000FFFFULL);
+			+ ((v >> 16) & 0x0000FFFF0000FFFFULL);
 		v = (v & 0x00000000FFFFFFFFULL)
-			+ ((v >> 1) & 0x00000000FFFFFFFFULL);
+			+ ((v >> 32) & 0x00000000FFFFFFFFULL);
 		return v;
 	}
 	val = (val & 0x55555555ULL) + ((val >> 1) & 0x55555555ULL);
-	val = (val & 0x33333333ULL) + ((val >> 1) & 0x33333333ULL);
-	val = (val & 0x0F0F0F0FULL) + ((val >> 1) & 0x0F0F0F0FULL);
-	val = (val & 0x00FF00FFULL) + ((val >> 1) & 0x00FF00FFULL);
-	val = (val & 0x0000FFFFULL) + ((val >> 1) & 0x0000FFFFULL);
+	val = (val & 0x33333333ULL) + ((val >> 2) & 0x33333333ULL);
+	val = (val & 0x0F0F0F0FULL) + ((val >> 4) & 0x0F0F0F0FULL);
+	val = (val & 0x00FF00FFULL) + ((val >> 8) & 0x00FF00FFULL);
+	val = (val & 0x0000FFFFULL) + ((val >> 16) & 0x0000FFFFULL);
 	return val;
 #endif
 }