diff --git a/src/mapgen/mapgen.cpp b/src/mapgen/mapgen.cpp
index 7984ff609..1c6395599 100644
--- a/src/mapgen/mapgen.cpp
+++ b/src/mapgen/mapgen.cpp
@@ -238,7 +238,8 @@ u32 Mapgen::getBlockSeed(v3s16 p, s32 seed)
 
 u32 Mapgen::getBlockSeed2(v3s16 p, s32 seed)
 {
-	u32 n = 1619 * p.X + 31337 * p.Y + 52591 * p.Z + 1013 * seed;
+	// Unsigned magic seed prevents undefined behavior.
+	u32 n = 1619 * p.X + 31337 * p.Y + 52591 * p.Z + 1013U * seed;
 	n = (n >> 13) ^ n;
 	return (n * (n * n * 60493 + 19990303) + 1376312589);
 }
diff --git a/src/noise.cpp b/src/noise.cpp
index a10efa3c4..46067e09d 100644
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -35,7 +35,8 @@
 #define NOISE_MAGIC_X    1619
 #define NOISE_MAGIC_Y    31337
 #define NOISE_MAGIC_Z    52591
-#define NOISE_MAGIC_SEED 1013
+// Unsigned magic seed prevents undefined behavior.
+#define NOISE_MAGIC_SEED 1013U
 
 typedef float (*Interp2dFxn)(
 		float v00, float v10, float v01, float v11,