ft(interpreter): impl shift and rotate

src/interpreter/computer.rs

@@ -235,6 +235,47 @@ impl Computer {
             ModRmTarget::Register(reg) => self.regs.read(reg),
         }
     }
+
+    pub fn rotate(
+        &mut self,
+        target: ModRmTarget,
+        rotations: usize,                      // how many rotations
+        carry_usage: CarryUsage, // if carry should be included, or should just receive a copy
+        rotation_direction: RotationDirection, // direction of rotation
+    ) {
+        let mut bits = self.read_modrm(target).bits();
+        match carry_usage {
+            CarryUsage::FullRotation => bits.push(self.flags.cf),
+            _ => {}
+        }
+        match rotation_direction {
+            RotationDirection::Left => {
+                bits.rotate_left(rotations);
+                match carry_usage {
+                    CarryUsage::ReceiveCopy => self.flags.cf = bits[7],
+                    CarryUsage::FullRotation => self.flags.cf = bits.pop().unwrap(),
+                }
+            }
+            RotationDirection::Right => {
+                bits.rotate_right(rotations);
+                match carry_usage {
+                    CarryUsage::ReceiveCopy => self.flags.cf = bits[0],
+                    CarryUsage::FullRotation => self.flags.cf = bits.pop().unwrap(),
+                }
+            }
+        }
+        self.write_modrm(target, ImmediateOperand::from(bits));
+    }
+}
+
+pub enum RotationDirection {
+    Left,
+    Right,
+}
+
+pub enum CarryUsage {
+    ReceiveCopy,  // dont add when rotating, but copy bit that was rotated to other side
+    FullRotation, // include in full rotation
 }
 
 impl fmt::Display for Computer {