diff --git a/go.mod b/go.mod
index 8393317..f8f1e6f 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module pgregory.net/rapid
 
-go 1.12
+go 1.14
diff --git a/utils.go b/utils.go
index 3499aaf..9c1ee18 100644
--- a/utils.go
+++ b/utils.go
@@ -24,7 +24,7 @@ func bitmask64(n uint) uint64 {
 }
 
 func genFloat01(s bitStream) float64 {
-	return float64(s.drawBits(53)) / (1 << 53)
+	return float64(s.drawBits(53)) * 0x1.0p-53
 }
 
 func genGeom(s bitStream, p float64) uint64 {