report memory sizes for push, pop, call, ret

these instructions had memory sizes reported for the operand, if it was
a memory operand, but for versions with non-memory operands the decoded
`Instruction` would imply that non memory access would happen at all.
now, decoded instructions in these cases will report a more useful
memory size.

1 files changed, 18 insertions, 0 deletions

diff --git a/test/long_mode/operand.rs b/test/long_mode/operand.rs
index 7be8d82..4cdaf35 100644
--- a/test/long_mode/operand.rs
+++ b/test/long_mode/operand.rs
@@ -28,3 +28,21 @@ fn memory_widths() {
     assert_eq!(mem_size_of(&[0x33, 0x00]).size_name(), "dword");
     assert_eq!(mem_size_of(&[0x48, 0x33, 0x00]).size_name(), "qword");
 }
+
+#[test]
+fn test_implied_memory_width() {
+    fn mem_size_of(data: &[u8]) -> Option<u8> {
+        let decoder = InstDecoder::default();
+        decoder.decode_slice(data).unwrap().mem_size().unwrap().bytes_size()
+    }
+
+    // test push, pop, call, and ret
+    assert_eq!(mem_size_of(&[0xc3]), Some(8));
+    assert_eq!(mem_size_of(&[0xe8, 0x11, 0x22, 0x33, 0x44]), Some(8));
+    assert_eq!(mem_size_of(&[0x50]), Some(8));
+    assert_eq!(mem_size_of(&[0x58]), Some(8));
+    assert_eq!(mem_size_of(&[0x66, 0x50]), Some(8));
+    assert_eq!(mem_size_of(&[0x66, 0x58]), Some(8));
+    assert_eq!(mem_size_of(&[0xff, 0xf0]), Some(8));
+    assert_eq!(mem_size_of(&[0x66, 0xff, 0xf0]), Some(2));
+}