Add operand size detection for fetching operands

1 files changed, 18 insertions, 2 deletions

diff --git a/src/core.rs b/src/core.rs
index 7779dab..a05d75e 100644
--- a/src/core.rs
+++ b/src/core.rs
@@ -80,6 +80,19 @@ impl fmt::Display for Op {
     }
 }
 
+impl Operand {
+    fn size(&self) -> usize {
+        match self {
+            Operand::Acc => 0,
+            Operand::Direct(_) => 1,
+            Operand::Indirect(_) => 0,
+            Operand::Data(_) => 1,
+            Operand::Register(_) => 0,
+            Operand::Reladdr(_) => 1,
+        }
+    }
+}
+
 pub struct Core {
     pc: u16,
     ram: Ram,
@@ -116,9 +129,12 @@ impl Core {
         } else {
             None
         };
+        let operand2_offset = match &operand1 {
+            Some(o) => o.size(),
+            _ => 0,
+        };
         let operand2 = if let Some(operand) = op.operand2 {
-            // TODO: offset must be based on operand1's size
-            Some(self.map_operand(operand, 2))
+            Some(self.map_operand(operand, operand2_offset))
         } else {
             None
         };