From 3c9562a4482ec6362c5bd49a3728905ac3ee2b26 Mon Sep 17 00:00:00 2001
From: Daniel Grund <grund@cs.uni-saarland.de>
Date: Tue, 19 Jul 2005 14:22:51 +0000
Subject: [PATCH] newest biset from libcore

[r6243]
---
 ir/adt/bitset.h | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/ir/adt/bitset.h b/ir/adt/bitset.h
index 62f44f9a5..937940cf9 100644
--- a/ir/adt/bitset.h
+++ b/ir/adt/bitset.h
@@ -245,7 +245,6 @@ static INLINE bitset_pos_t bitset_max(const bitset_t *bs)
  * @note Note that if pos is set, pos is returned.
  * @param bs The bitset.
  * @param pos The bit from which to search for the next set bit.
- * @param set if 1, serach for set bits, else for unset bits
  * @return The next set bit from pos on, or -1, if no set bit was found
  * after pos.
  */
@@ -384,6 +383,27 @@ static INLINE int bitset_contains(const bitset_t *lhs, const bitset_t *rhs)
 	return 1;
 }
 
+/**
+ * Treat the bitset as a number and subtract 1.
+ * @param bs The bitset.
+ * @return The same bitset.
+ */
+static INLINE void bitset_minus1(bitset_t *bs)
+{
+#define _SH (sizeof(bitset_unit_t) * 8 - 1)
+
+  for(i = 0; i < bs->units; ++i) {
+    bitset_unit_t unit = bs->data[i];
+    bitset_unit_t um1  = unit - 1;
+
+    bs->data[i] = um1;
+
+    if(((unit >> _SH) ^ (um1 >> _SH)) == 0)
+      break;
+  }
+#undef _SH
+}
+
 /**
  * Print a bitset to a stream.
  * The bitset is printed as a comma seperated list of bits set.
-- 
2.20.1