diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index c46fbf6..4ec4351 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -6314,7 +6314,7 @@ fetchtok:
   case tRATIONAL:
     if (!allow_nonint)
       goto invalid_token;
-    p->value.ucell=(ucell)(negate ? (val|((cell)1 << (PAWN_CELL_SIZE-1))) : val);
+    p->value.ucell=(negate ? ((ucell)val|((ucell)1 << (PAWN_CELL_SIZE-1))) : (ucell)val);
     break;
   case tSYMBOL:
     sym=findloc(str);
diff --git a/source/compiler/sc2.c b/source/compiler/sc2.c
index b611086..b4c97dd 100644
--- a/source/compiler/sc2.c
+++ b/source/compiler/sc2.c
@@ -1405,7 +1405,7 @@ static int command(void)
               break;
             } else if (current_token==tRATIONAL) {
               /* change the first bit to make float negative value */
-              outval(val|((cell)1 << (PAWN_CELL_SIZE-1)),FALSE);
+              outval(val|(cell)((ucell)1 << (PAWN_CELL_SIZE-1)),FALSE);
               code_idx+=opargs(1);
               break;
             } else {