util: Make raw_ctz() accept 64-bit integers.

[sliver-openvswitch.git] / lib / util.h

diff --git a/lib/util.h b/lib/util.h
index 32a7c8c..91dc0a5 100644 (file)
--- a/lib/util.h
+++ b/lib/util.h
@@ -264,6 +264,8 @@ bool str_to_uint(const char *, int base, unsigned int *);
 bool str_to_ulong(const char *, int base, unsigned long *);
 bool str_to_ullong(const char *, int base, unsigned long long *);
 
+bool ovs_scan(const char *s, const char *template, ...) SCANF_FORMAT(2, 3);
+
 bool str_to_double(const char *, double *);
 
 int hexit_value(int c);
@@ -283,20 +285,40 @@ void ignore(bool x OVS_UNUSED);
 \f
 /* Bitwise tests. */
 
-/* Returns the number of trailing 0-bits in 'n'.  Undefined if 'n' == 0.
- *
- * This compiles to a single machine instruction ("bsf") with GCC on x86. */
-#if !defined(UINT_MAX) || !defined(UINT32_MAX)
-#error "Someone screwed up the #includes."
-#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+int log_2_floor(uint32_t);
+int log_2_ceil(uint32_t);
+unsigned int popcount(uint32_t);
+
+/* Returns the number of trailing 0-bits in 'n'.  Undefined if 'n' == 0. */
+#if __GNUC__ >= 4
 static inline int
-raw_ctz(uint32_t n)
+raw_ctz(uint64_t n)
 {
-    return __builtin_ctz(n);
+    /* With GCC 4.7 on 32-bit x86, if a 32-bit integer is passed as 'n', using
+     * a plain __builtin_ctzll() here always generates an out-of-line function
+     * call.  The test below helps it to emit a single 'bsf' instruction. */
+    return (__builtin_constant_p(n <= UINT32_MAX) && n <= UINT32_MAX
+            ? __builtin_ctz(n)
+            : __builtin_ctzll(n));
 }
 #else
 /* Defined in util.c. */
-int raw_ctz(uint32_t n);
+int raw_ctz(uint64_t n);
+#endif
+
+#if __GNUC__ >= 4
+static inline int
+popcount64(uint64_t n)
+{
+    return __builtin_popcountll(n);
+}
+#else
+/* Defined using the 32-bit counterparts. */
+static inline int
+popcount64(uint64_t n)
+{
+    return popcount(n) + popcount(n >> 32);
+}
 #endif
 
 /* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */
@@ -306,9 +328,12 @@ ctz(uint32_t n)
     return n ? raw_ctz(n) : 32;
 }
 
-int log_2_floor(uint32_t);
-int log_2_ceil(uint32_t);
-unsigned int popcount(uint32_t);
+/* Returns the number of trailing 0-bits in 'n', or 64 if 'n' is 0. */
+static inline int
+ctz64(uint64_t n)
+{
+    return n ? raw_ctz(n) : 64;
+}
 
 /* Returns the rightmost 1-bit in 'x' (e.g. 01011000 => 00001000), or 0 if 'x'
  * is 0. */