We can provide fast versions based on the other functions defined
by host-utils.h. Some care is required on glibc, which provides
ffsl already.
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
host-utils.h | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/host-utils.h b/host-utils.h
index 821db93..4250eb0 100644
--- a/host-utils.h
+++ b/host-utils.h
@@ -24,6 +24,7 @@
*/
#include "compiler.h" /* QEMU_GNUC_PREREQ */
+#include <string.h> /* ffsl */
#if defined(__x86_64__)
#define __HAVE_FAST_MULU64__
@@ -234,3 +235,47 @@ static inline int ctpop64(uint64_t val)
return val;
#endif
}
+
+/* glibc does not provide an inline version of ffsl, so always define
+ * ours.
+ */
+#ifdef __GLIBC__
+#define ffsl qemu_ffsl
+#endif
+static inline int ffsl(long val)
+{
+ if (!val) {
+ return 0;
+ }
+
+#if QEMU_GNUC_PREREQ(3, 4)
+ return __builtin_ctzl(val) + 1;
+#else
+ if (sizeof(long) == 4) {
+ return ctz32(val) + 1;
+ } else if (sizeof(long) == 8) {
+ return ctz64(val) + 1;
+ } else {
+ abort();
+ }
+#endif
+}
+
+static inline int flsl(long val)
+{
+ if (!val) {
+ return 0;
+ }
+
+#if QEMU_GNUC_PREREQ(3, 4)
+ return __builtin_clzl(val) + 1;
+#else
+ if (sizeof(long) == 4) {
+ return clz32(val) + 1;
+ } else if (sizeof(long) == 8) {
+ return clz64(val) + 1;
+ } else {
+ abort();
+ }
+#endif
+}
--
1.7.10.4
