diff --git a/LOG b/LOG
index 1c9560bf04..cf7b4dc347 100644
--- a/LOG
+++ b/LOG
@@ -1313,3 +1313,5 @@
     externs.h, system.h, expeditor.c, configure, Mf-*, Makefile.*nt,
     workarea, mat.ss, io.ms, io.stex, objects.stex, release_notes.stex,
     root-experr*, patch*
+- fix multiply of most negative fixnum to itself on 64-bit platforms
+    number.c, 5_3.ms
diff --git a/c/number.c b/c/number.c
index a7930eefff..1fd2f4b308 100644
--- a/c/number.c
+++ b/c/number.c
@@ -637,7 +637,7 @@ static ptr big_mul(tc, x, y, xl, yl, sign) ptr tc, x, y; iptr xl, yl; IBOOL sign
   return copy_normalize(&BIGIT(W(tc),0),xl+yl,sign);
 }
 
-#define SHORTMIN (most_negative_fixnum / (1 << (fixnum_bits / 2)))
+#define SHORTMIN ((most_negative_fixnum / (1 << (fixnum_bits / 2))) + 1)
 #define SHORTMAX (most_positive_fixnum / (1 << (fixnum_bits / 2)))
 #define SHORTRANGE(x) ((x) >= SHORTMIN && (x) <= SHORTMAX)
 
diff --git a/mats/5_3.ms b/mats/5_3.ms
index fc84f82118..5d3bc41214 100644
--- a/mats/5_3.ms
+++ b/mats/5_3.ms
@@ -1628,6 +1628,14 @@
     (error? (* 'a 3 4))
     (error? (* 3 5 'a 4))
     (eqv? (* 1 2) 2)
+    (let loop ([n 0])
+      (or (= n 100)
+          (and
+           (eqv? (* (expt 2 n) (expt 2 n)) (expt 2 (* 2 n)))
+           (eqv? (* (- (expt 2 n)) (- (expt 2 n))) (expt 2 (* 2 n)))
+           (eqv? (* (- (expt 2 n)) (expt 2 n)) (- (expt 2 (* 2 n))))
+           (eqv? (* (expt 2 n) (- (expt 2 n))) (- (expt 2 (* 2 n))))
+           (loop (add1 n)))))
     (fl~= (* 1.0 2) 2.0)
     (fl~= (* 1 2.0) 2.0)
     (eqv? (* 3/5 2/5) 6/25)