0124

src/programmer.rs

@@ -699,4 +699,35 @@ mod tests {
         assert_eq!(p.word_size(), WordSize::Dint);
         assert_eq!(p.dec_text().replace(' ', ""), "-1");
     }
+
+    #[test]
+    fn shift_count_mods_word_size() {
+        // Locks hardware-style semantics: shift count is taken modulo the
+        // word size (1 << 100000000 → 1e8 % 64 == 0 → no shift).
+        let mut p = Programmer::new();
+        p.input_digit('1');
+        p.set_op(ProgOp::Lsh);
+        for ch in "100000000".chars() {
+            p.input_digit(ch);
+        }
+        p.equals();
+        assert_eq!(p.current_bits(), 1);
+    }
+
+    #[test]
+    fn shift_out_of_word_gives_zero() {
+        // 0xFFFF_FFFF_FFFF_FFFF Lsh 63 → only bit 0 survives at bit 63.
+        let mut p = Programmer::new();
+        p.set_base(Base::Hex);
+        for ch in "FFFFFFFFFFFFFFFF".chars() {
+            p.input_digit(ch);
+        }
+        p.set_op(ProgOp::Lsh);
+        p.set_base(Base::Dec); // type the shift count in decimal
+        p.input_digit('6');
+        p.input_digit('3');
+        p.equals();
+        // (u64::MAX << 63) & u64::MAX = 0x8000_0000_0000_0000
+        assert_eq!(p.current_bits(), 0x8000_0000_0000_0000);
+    }
 }