Fixed two compiler warnings.

[cc65] / src / cc65 / loadexpr.c

diff --git a/src/cc65/loadexpr.c b/src/cc65/loadexpr.c
index 8e7f83b76177dc87a55d25750d945d96fb4750b6..99c5684d16f4242245b53b969377fb915ca31a24 100644 (file)
--- a/src/cc65/loadexpr.c
+++ b/src/cc65/loadexpr.c
@@ -95,8 +95,17 @@ void LoadExpr (unsigned Flags, struct ExprDesc* Expr)
 {
     if (ED_IsLVal (Expr)) {
 
-               /* Dereferenced lvalue */
-               Flags |= TypeOf (Expr->Type);
+               /* Dereferenced lvalue. If this is a bit field its type is unsigned.
+         * But if the field is completely contained in the lower byte, we will
+         * throw away the high byte anyway and may therefore load just the
+         * low byte.
+         */
+        if (ED_IsBitField (Expr)) {
+            Flags |= (Expr->BitOffs + Expr->BitWidth <= CHAR_BITS)? CF_CHAR : CF_INT;
+            Flags |= CF_UNSIGNED;
+        } else {
+            Flags |= TypeOf (Expr->Type);
+        }
        if (ED_NeedsTest (Expr)) {
            Flags |= CF_TEST;
        }
@@ -153,8 +162,11 @@ void LoadExpr (unsigned Flags, struct ExprDesc* Expr)
             unsigned F = CF_INT | CF_UNSIGNED | CF_CONST | (Flags & CF_TEST);
             /* Shift right by the bit offset */
             g_asr (F, Expr->BitOffs);
-            /* And by the width */
-            g_and (F, (0x0001U << Expr->BitWidth) - 1U);
+            /* And by the width if the field doesn't end on an int boundary */
+            if (Expr->BitOffs + Expr->BitWidth != CHAR_BITS &&
+                Expr->BitOffs + Expr->BitWidth != INT_BITS) {
+                g_and (F, (0x0001U << Expr->BitWidth) - 1U);
+            }
         }
 
         /* Expression was tested */