diff --git a/common/coords.go b/common/coords.go
index b714d07..a3b2318 100644
--- a/common/coords.go
+++ b/common/coords.go
@@ -252,8 +252,8 @@ func NaiveBigMin(minz, maxz, zcode int64) int64 {
 const (
 	bits = 12
 	msb  = uint8(3*bits - 1)
-	mask = int64(0x924924924924924)
-	full = int64(0xfffffffffffffff)
+	mask = int64(0x924924924)
+	full = int64(0xfffffffff)
 )
 
 func setbits(p uint8, v int64) int64 {