diff --git a/vu/select.c b/vu/select.c
index ed6d398..40d9ad1 100644
--- a/vu/select.c
+++ b/vu/select.c
@@ -230,8 +230,11 @@ INLINE static void do_ch(short* VD, short* VS, short* VT)
 #ifndef _DEBUG
     short diff[N];
 #endif
+    i16 cch[N]; /* corner case hack:  -(-32768) with undefined sign */
     register int i;
 
+    for (i = 0; i < N; i++)
+        cch[i] = (VT[i] == -32768) ? ~0 : 0; /* -(-32768) might not be >= 0. */
     vector_copy(VC, VT);
     for (i = 0; i < N; i++)
         sn[i] = VS[i] ^ VT[i];
@@ -244,9 +247,9 @@ INLINE static void do_ch(short* VD, short* VS, short* VT)
     for (i = 0; i < N; i++)
         vce[i] &= sn[i];
     for (i = 0; i < N; i++)
-        VC[i] -= sn[i]; /* converts ~(VT) into -(VT) if (sign) */
+        VC[i] -= sn[i] & cch[i]; /* converts ~(VT) into -(VT) if (sign) */
     for (i = 0; i < N; i++)
-        eq[i]  = (VS[i] == VC[i]);
+        eq[i]  = (VS[i] == VC[i]) & ~cch[i]; /* (VS == +32768) is never true. */
     for (i = 0; i < N; i++)
         eq[i] |= vce[i];