1 files changed, 80 insertions, 0 deletions
diff --git a/src/cmd/gc/bv.c b/src/cmd/gc/bv.c
new file mode 100644
index 000000000..92834a97b
--- /dev/null
+++ b/src/cmd/gc/bv.c
@@ -0,0 +1,80 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include <u.h>
+#include <libc.h>
+#include "go.h"
+
+enum {
+	WORDSIZE = sizeof(uint32),
+	WORDBITS = 32,
+};
+
+uintptr
+bvsize(uintptr n)
+{
+	return ((n + WORDBITS - 1) / WORDBITS) * WORDSIZE;
+}
+
+Bvec*
+bvalloc(int32 n)
+{
+	Bvec *bv;
+	uintptr nbytes;
+
+	if(n < 0)
+		fatal("bvalloc: initial size is negative\n");
+	nbytes = sizeof(Bvec) + bvsize(n);
+	bv = malloc(nbytes);
+	if(bv == nil)
+		fatal("bvalloc: malloc failed\n");
+	memset(bv, 0, nbytes);
+	bv->n = n;
+	return bv;
+}
+
+void
+bvset(Bvec *bv, int32 i)
+{
+	uint32 mask;
+
+	if(i < 0 || i >= bv->n)
+		fatal("bvset: index %d is out of bounds with length %d\n", i, bv->n);
+	mask = 1U << (i % WORDBITS);
+	bv->b[i / WORDBITS] |= mask;
+}
+
+void
+bvres(Bvec *bv, int32 i)
+{
+	uint32 mask;
+
+	if(i < 0 || i >= bv->n)
+		fatal("bvres: index %d is out of bounds with length %d\n", i, bv->n);
+	mask = ~(1 << (i % WORDBITS));
+	bv->b[i / WORDBITS] &= mask;
+}
+
+int
+bvget(Bvec *bv, int32 i)
+{
+	uint32 mask, word;
+
+	if(i < 0 || i >= bv->n)
+		fatal("bvget: index %d is out of bounds with length %d\n", i, bv->n);
+	mask = 1 << (i % WORDBITS);
+	word = bv->b[i / WORDBITS] & mask;
+	return word ? 1 : 0;
+}
+
+int
+bvisempty(Bvec *bv)
+{
+	int32 i;
+
+	for(i = 0; i < bv->n; i += WORDBITS)
+		if(bv->b[i / WORDBITS] != 0)
+			return 0;
+	return 1;
+}