implement signed integer extension operations

crates/wasm_interp/src/instance.rs

@@ -1728,6 +1728,26 @@ impl<'a, I: ImportDispatcher> Instance<'a, I> {
                 self.value_store
                     .push(Value::F64(f64::from_ne_bytes(x.to_ne_bytes())));
             }
+            I32EXTEND8S => {
+                let x = self.value_store.pop_i32()?;
+                self.value_store.push(Value::I32(x as i8 as i32));
+            }
+            I32EXTEND16S => {
+                let x = self.value_store.pop_i32()?;
+                self.value_store.push(Value::I32(x as i16 as i32));
+            }
+            I64EXTEND8S => {
+                let x = self.value_store.pop_i64()?;
+                self.value_store.push(Value::I64(x as i8 as i64));
+            }
+            I64EXTEND16S => {
+                let x = self.value_store.pop_i64()?;
+                self.value_store.push(Value::I64(x as i16 as i64));
+            }
+            I64EXTEND32S => {
+                let x = self.value_store.pop_i64()?;
+                self.value_store.push(Value::I64(x as i32 as i64));
+            }
         }
 
         if let Some(debug_string) = &self.debug_string {

crates/wasm_interp/src/tests/test_convert.rs

@@ -247,3 +247,48 @@ fn test_f64reinterpreti64() {
         Value::F64(0.01171875),
     );
 }
+
+#[test]
+fn test_i32extend8s() {
+    test_op_example(
+        I32EXTEND8S,
+        [Value::from(0xFFu32 as i32)],
+        Value::I32(0xFFFFFFFFu32 as i32),
+    )
+}
+
+#[test]
+fn test_i32extend16s() {
+    test_op_example(
+        I32EXTEND16S,
+        [Value::from(0xFFFFu32)],
+        Value::I32(0xFFFFFFFFu32 as i32),
+    )
+}
+
+#[test]
+fn test_i64extend8s() {
+    test_op_example(
+        I64EXTEND8S,
+        [Value::from(0xFFu64 as i64)],
+        Value::I64(u64::MAX as i64),
+    )
+}
+
+#[test]
+fn test_i64extend16s() {
+    test_op_example(
+        I64EXTEND16S,
+        [Value::from(0xFFFFu64 as i64)],
+        Value::I64(u64::MAX as i64),
+    )
+}
+
+#[test]
+fn test_i64extend32s() {
+    test_op_example(
+        I64EXTEND32S,
+        [Value::from(0xFFFFFFFFu64 as i64)],
+        Value::I64(u64::MAX as i64),
+    )
+}