diff --git a/common/block.go b/common/block.go
index 1f87478..fa342e3 100644
--- a/common/block.go
+++ b/common/block.go
@@ -290,10 +290,10 @@ func (db *DecodedBlock) Content(x, y, z int) (content int32, found bool) {
 		pos <<= 1
 		content = int32(db.MapContent[pos])<<8 | int32(db.MapContent[pos+1])
 	case db.Version >= 20:
-		if db.MapContent[pos] <= 0x80 {
-			content = int32(db.MapContent[pos])
+		if c := db.MapContent[pos]; c <= 0x80 {
+			content = int32(c)
 		} else {
-			content = int32(db.MapContent[pos])<<4 | int32(db.MapContent[pos+0x2000])>>4
+			content = int32(c)<<4 | int32(db.MapContent[pos+0x2000])>>4
 		}
 	default:
 		return