diff --git a/src/enc/vp8l_enc.c b/src/enc/vp8l_enc.c
index 2b345df6..713adddf 100644
--- a/src/enc/vp8l_enc.c
+++ b/src/enc/vp8l_enc.c
@@ -361,10 +361,11 @@ typedef enum {
   kHistoTotal  // Must be last.
 } HistoIx;
 
-static void AddSingleSubGreen(int p, uint32_t* const r, uint32_t* const b) {
-  const int green = p >> 8;  // The upper bits are masked away later.
-  ++r[((p >> 16) - green) & 0xff];
-  ++b[((p >>  0) - green) & 0xff];
+static void AddSingleSubGreen(uint32_t p,
+                              uint32_t* const r, uint32_t* const b) {
+  const int green = (int)p >> 8;  // The upper bits are masked away later.
+  ++r[(((int)p >> 16) - green) & 0xff];
+  ++b[(((int)p >>  0) - green) & 0xff];
 }
 
 static void AddSingle(uint32_t p,