diff --git a/pkgs/bitmap/bitmap.go b/pkgs/bitmap/bitmap.go
new file mode 100644
index 0000000..b1c3e63
--- /dev/null
+++ b/pkgs/bitmap/bitmap.go
@@ -0,0 +1,29 @@
+package bitmap
+
+type Bitmap64 uint64
+
+func (b *Bitmap64) Set(index int, val bool) {
+	if val {
+		*b |= 1 << index
+	} else {
+		*b &= ^(1 << index)
+	}
+}
+
+func (b *Bitmap64) Get(index int) bool {
+	return (*b & (1 << index)) > 0
+}
+
+func (b *Bitmap64) Or(other *Bitmap64) {
+	*b |= *other
+}
+
+func (b *Bitmap64) Weight() int {
+	v := *b
+	cnt := 0
+	for v > 0 {
+		cnt++
+		v &= (v - 1)
+	}
+	return cnt
+}