Add ADD opcode

coco-core/src/lib.rs

@@ -65,6 +65,7 @@ impl Cpu {
                 opcodes::DEI => self.op_dei(machine),
                 opcodes::DEO => self.op_deo(machine),
                 opcodes::DEO2 => self.op_deo2(machine),
+                opcodes::ADD => self.op_add(),
                 opcodes::SUB => self.op_sub(),
                 opcodes::MUL => self.op_mul(),
                 opcodes::DIV => self.op_div(),
@@ -177,6 +178,14 @@ impl Cpu {
         machine.deo(self, target);
     }
 
+    #[inline]
+    fn op_add(&mut self) {
+        let b = self.stack.pop_byte();
+        let a = self.stack.pop_byte();
+        let value = a.wrapping_add(b);
+        self.stack.push_byte(value);
+    }
+
     #[inline]
     fn op_sub(&mut self) {
         let b = self.stack.pop_byte();
@@ -363,6 +372,18 @@ mod tests {
         // TODO: check AnyMachine.deo has been called with 0xab as target arg
     }
 
+    #[test]
+    fn add_opcode() {
+        let rom = rom_from(&[PUSH, 0xab, PUSH, 0x02, ADD, BRK]);
+        let mut cpu = Cpu::new(&rom);
+
+        let pc = cpu.run(0x100, &mut AnyMachine {});
+
+        assert_eq!(pc, 0x106);
+        assert_eq!(cpu.stack.len(), 1);
+        assert_eq!(cpu.stack.byte_at(0), 0xad);
+    }
+
     #[test]
     fn sub_opcode() {
         let rom = rom_from(&[PUSH, 0xab, PUSH, 0x02, SUB, BRK]);

coco-core/src/opcodes.rs

@@ -4,6 +4,7 @@ pub const DUP: u8 = 0x06;
 pub const DUP2: u8 = 0x26;
 pub const DEI: u8 = 0x16;
 pub const DEO: u8 = 0x17;
+pub const ADD: u8 = 0x18;
 pub const SUB: u8 = 0x19;
 pub const MUL: u8 = 0x1a;
 pub const DIV: u8 = 0x1b;