diff --git a/zsnes/src/video/procvid.asm b/zsnes/src/video/procvid.asm
index 99d810c5..3cf8ec0f 100644
--- a/zsnes/src/video/procvid.asm
+++ b/zsnes/src/video/procvid.asm
@@ -2736,6 +2736,9 @@ NEWSYM ClockOutput
     ; eax = hours
     cmp byte[TwelveHourClock],1
     jne .no12hour
+    ; check to see if it's 12 PM
+    cmp eax,12
+    jbe .no12hour
     sub eax,12
 .no12hour
     xor edx,edx