diff --git a/sim/msp430/ChangeLog b/sim/msp430/ChangeLog
index 4b76a03a15..77ea38008a 100644
--- a/sim/msp430/ChangeLog
+++ b/sim/msp430/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-12  DJ Delorie  <dj@redhat.com>
+
+	* msp43-sim.c (sign_ext): Change to "long long" to support
+	sign-extending 32-bit values.
+
 2014-05-08  Nick Clifton  <nickc@redhat.com>
 
 	* msp430-sim.c (sim_open): Do not allocate memory over the
diff --git a/sim/msp430/msp430-sim.c b/sim/msp430/msp430-sim.c
index 693fdee627..2dcbae3378 100644
--- a/sim/msp430/msp430-sim.c
+++ b/sim/msp430/msp430-sim.c
@@ -337,11 +337,11 @@ zero_ext (unsigned int v, unsigned int bits)
   return v;
 }
 
-static signed int
-sign_ext (signed int v, unsigned int bits)
+static signed long long
+sign_ext (signed long long v, unsigned int bits)
 {
-  int sb = 1 << (bits-1);	/* Sign bit.  */
-  int mb = (1 << (bits-1)) - 1; /* Mantissa bits.  */
+  signed long long sb = 1LL << (bits-1);	/* Sign bit.  */
+  signed long long mb = (1LL << (bits-1)) - 1LL; /* Mantissa bits.  */
 
   if (v & sb)
     v = v | ~mb;