diff --git a/xwin.c b/xwin.c
index 548943c..f6c71f6 100644
--- a/xwin.c
+++ b/xwin.c
@@ -662,6 +662,7 @@ translate16to32(const uint16 * data, uint8 * out, uint8 * end)
 		}
 		else
 		{
+			while (out < end)
 			{
 				pixel = *(data++);
 				SPLITCOLOUR16(pixel, pc);