diff --git a/sim/ppc/ChangeLog b/sim/ppc/ChangeLog
index 2b324d5473..65ff71e3ae 100644
--- a/sim/ppc/ChangeLog
+++ b/sim/ppc/ChangeLog
@@ -1,3 +1,8 @@
+2000-03-25  Geoff Keating  <geoffk@cygnus.com>
+
+	* ppc-instructions (Disabled_Exponent_Underflow): Increment
+	the exponent when denormalizing.
+
 Thu Sep  2 18:15:53 1999  Andrew Cagney  <cagney@b1.cygnus.com>
 
 	* configure: Regenerated to track ../common/aclocal.m4 changes.
diff --git a/sim/ppc/ppc-instructions b/sim/ppc/ppc-instructions
index cfbac643e3..b9a3287e38 100644
--- a/sim/ppc/ppc-instructions
+++ b/sim/ppc/ppc-instructions
@@ -4282,7 +4282,7 @@ void::function::invalid_zero_divide_operation:cpu *processor, unsigned_word cia,
 	  }
 	    /* G|R|X == zero from above */
 	    while (exp < -126) {
-	      exp = exp - 1;
+	      exp = exp + 1;
 	      frac_grx = (INSERTED64(EXTRACTED64(frac_grx, 0, 54), 1, 55)
 	                  | MASKED64(frac_grx, 55, 55));
 	    }