diff --git a/lib/fast486/common.inl b/lib/fast486/common.inl
index 97c5d4e309b..fff8fc01474 100644
--- a/lib/fast486/common.inl
+++ b/lib/fast486/common.inl
@@ -296,7 +296,7 @@ Fast486StackPush(PFAST486_STATE State,
         USHORT ShortValue = LOWORD(Value);
 
         /* Check if SP is 1 */
-        if (State->GeneralRegs[FAST486_REG_ESP].Long == 1)
+        if (State->GeneralRegs[FAST486_REG_ESP].LowWord == 1)
         {
             Fast486Exception(State, FAST486_EXCEPTION_SS);
             return FALSE;
diff --git a/lib/fast486/opgroups.c b/lib/fast486/opgroups.c
index 7480296a46e..0e560d5e151 100644
--- a/lib/fast486/opgroups.c
+++ b/lib/fast486/opgroups.c
@@ -1632,6 +1632,9 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeGroupFF)
         {
             /* Set the IP to the address */
             State->InstPtr.LowWord = Value;
+
+            /* Clear the top half of EIP */
+            State->InstPtr.Long &= 0xFFFF;
         }
         else if (ModRegRm.Register == 5)
         {