From 5e5655e778d1df7427aa4fe6462e7741de24b1b2 Mon Sep 17 00:00:00 2001
From: Jeff Squyres <jsquyres@cisco.com>
Date: Wed, 21 Apr 2004 00:40:08 +0000
Subject: [PATCH] Add an inline hibit calculation function

This commit was SVN r1073.
---
 src/util/Makefile.am |  1 +
 src/util/hibit.h     | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 src/util/hibit.h

diff --git a/src/util/Makefile.am b/src/util/Makefile.am
index 19785d7d93..7bbb5ba131 100644
--- a/src/util/Makefile.am
+++ b/src/util/Makefile.am
@@ -13,6 +13,7 @@ headers = \
     argv.h \
     cmd_line.h \
     few.h \
+    hibit.h \
     if.h \
     output.h \
     path.h \
diff --git a/src/util/hibit.h b/src/util/hibit.h
new file mode 100644
index 0000000000..6942d74ea0
--- /dev/null
+++ b/src/util/hibit.h
@@ -0,0 +1,38 @@
+/*
+ * $HEADER$
+ */
+
+#ifndef LAM_HIBIT_H
+#define LAM_HIBIT_H
+
+/**
+ * Calculates the highest bit in an integer
+ *
+ * @param value The integer value to examine
+ * @param start Position to start looking
+ *
+ * @returns pos Position of highest-set integer or -1 if none are set.
+ *
+ * Look at the integer "value" starting at position "start", and move
+ * to the right.  Return the index of the highest bit that is set to
+ * 1.
+ *
+ * WARNING: *NO* error checking is performed.  This is meant to be a
+ * fast inline function.
+ */
+static inline int lam_hibit(int value, int start)
+{
+  unsigned int mask;
+
+  --start;
+  mask = 1 << start;
+
+  for (; start >= 0; --start, mask >>= 1) {
+    if (value & mask) 
+      break;
+  }
+  
+  return start;
+}
+
+#endif /* LAM_HIBIT_H */