1 files changed, 37 insertions, 0 deletions
diff --git a/common/util.c b/common/util.c
new file mode 100644
index 0000000000..36afdd4470
--- /dev/null
+++ b/common/util.c
@@ -0,0 +1,37 @@
+/*
+Copyright 2011 Jun Wako <wakojun@gmail.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "util.h"
+
+// bit population
+int bitpop(uint8_t bits)
+{
+    int c;
+    for (c = 0; bits; c++)
+        bits &= bits -1;
+    return c;
+}
+
+// most significant on-bit
+int biton(uint8_t bits)
+{
+    int n = 0;
+    if (bits >> 4) { bits >>= 4; n += 4;}
+    if (bits >> 2) { bits >>= 2; n += 2;}
+    if (bits >> 1) { bits >>= 1; n += 1;}
+    return n;
+}