Add a macro for binary ops and use it for ADD2, SUB2, MUL2 and DIV2 (#14

)

coco-core/src/lib.rs

@@ -5,9 +5,11 @@ use core::cmp;
 use core::fmt;
 
 mod stack;
+use opcodes::short_mode;
 use stack::Stack;
 
 pub mod opcodes;
+use opcodes::FLAG_SHORT;
 
 /// The trait to implement for COCO virtual machines.
 pub trait Machine {
@@ -20,6 +22,22 @@ pub trait Ports {
     const BASE: u8;
 }
 
+macro_rules! binary_op {
+    ($self:ident, $flags:ident, $f:expr) => {
+        if short_mode($flags) {
+            let b = $self.stack.pop_short();
+            let a = $self.stack.pop_short();
+            let f: fn(u16, u16) -> u16 = $f;
+            $self.stack.push_short(f(a, b))
+        } else {
+            let b = $self.stack.pop_byte();
+            let a = $self.stack.pop_byte();
+            let f: fn(u8, u8) -> u8 = $f;
+            $self.stack.push_byte(f(a, b))
+        }
+    };
+}
+
 /// COCO-8 CPU.
 #[derive(Debug)]
 pub struct Cpu {
@@ -65,10 +83,14 @@ 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(),
+                opcodes::ADD => self.op_add::<0x00>(),
+                opcodes::ADD2 => self.op_add::<FLAG_SHORT>(),
+                opcodes::SUB => self.op_sub::<0x00>(),
+                opcodes::SUB2 => self.op_sub::<FLAG_SHORT>(),
+                opcodes::MUL => self.op_mul::<0x00>(),
+                opcodes::MUL2 => self.op_mul::<FLAG_SHORT>(),
+                opcodes::DIV => self.op_div::<0x00>(),
+                opcodes::DIV2 => self.op_div::<FLAG_SHORT>(),
                 opcodes::PUSH => self.op_push(),
                 opcodes::PUSH2 => self.op_push2(),
                 _ => {}
@@ -179,35 +201,23 @@ impl Cpu {
     }
 
     #[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);
+    fn op_add<const FLAGS: u8>(&mut self) {
+        binary_op!(self, FLAGS, |a, b| a.wrapping_add(b))
     }
 
     #[inline]
-    fn op_sub(&mut self) {
-        let b = self.stack.pop_byte();
-        let a = self.stack.pop_byte();
-        let value = a.wrapping_sub(b);
-        self.stack.push_byte(value);
+    fn op_sub<const FLAGS: u8>(&mut self) {
+        binary_op!(self, FLAGS, |a, b| a.wrapping_sub(b))
     }
 
     #[inline]
-    fn op_mul(&mut self) {
-        let b = self.stack.pop_byte();
-        let a = self.stack.pop_byte();
-        let value = a.wrapping_mul(b);
-        self.stack.push_byte(value);
+    fn op_mul<const FLAGS: u8>(&mut self) {
+        binary_op!(self, FLAGS, |a, b| a.wrapping_mul(b))
     }
 
     #[inline]
-    fn op_div(&mut self) {
-        let b = self.stack.pop_byte();
-        let a = self.stack.pop_byte();
-        let value = a.wrapping_div(b);
-        self.stack.push_byte(value);
+    fn op_div<const FLAGS: u8>(&mut self) {
+        binary_op!(self, FLAGS, |a, b| a.wrapping_div(b))
     }
 }
 
@@ -384,6 +394,18 @@ mod tests {
         assert_eq!(cpu.stack.byte_at(0), 0xad);
     }
 
+    #[test]
+    fn add2_opcode() {
+        let rom = rom_from(&[PUSH2, 0xab, 0xcd, PUSH2, 0x11, 0x11, ADD2, BRK]);
+        let mut cpu = Cpu::new(&rom);
+
+        let pc = cpu.run(0x100, &mut AnyMachine {});
+
+        assert_eq!(pc, 0x108);
+        assert_eq!(cpu.stack.len(), 2);
+        assert_eq!(cpu.stack.short_at(0), 0xbcde);
+    }
+
     #[test]
     fn sub_opcode() {
         let rom = rom_from(&[PUSH, 0xab, PUSH, 0x02, SUB, BRK]);
@@ -396,6 +418,18 @@ mod tests {
         assert_eq!(cpu.stack.byte_at(0), 0xa9);
     }
 
+    #[test]
+    fn sub2_opcode() {
+        let rom = rom_from(&[PUSH2, 0xab, 0xcd, PUSH2, 0x11, 0x11, SUB2, BRK]);
+        let mut cpu = Cpu::new(&rom);
+
+        let pc = cpu.run(0x100, &mut AnyMachine {});
+
+        assert_eq!(pc, 0x108);
+        assert_eq!(cpu.stack.len(), 2);
+        assert_eq!(cpu.stack.short_at(0), 0x9abc);
+    }
+
     #[test]
     fn mul_opcode() {
         let rom = rom_from(&[PUSH, 0x03, PUSH, 0x02, MUL, BRK]);

coco-core/src/opcodes.rs

@@ -4,10 +4,30 @@ pub const DUP: u8 = 0x06;
 pub const DUP2: u8 = 0x26;
 pub const DEI: u8 = 0x16;
 pub const DEO: u8 = 0x17;
+pub const DEO2: u8 = 0x37;
 pub const ADD: u8 = 0x18;
+pub const ADD2: u8 = 0x38;
 pub const SUB: u8 = 0x19;
+pub const SUB2: u8 = 0x39;
 pub const MUL: u8 = 0x1a;
+pub const MUL2: u8 = 0x3a;
 pub const DIV: u8 = 0x1b;
-pub const DEO2: u8 = 0x37;
+pub const DIV2: u8 = 0x3b;
 pub const PUSH: u8 = 0x80;
 pub const PUSH2: u8 = 0xa0;
+
+pub const FLAG_SHORT: u8 = 0b0010_0000;
+pub const FLAG_RET: u8 = 0b0100_0000;
+pub const FLAG_KEEP: u8 = 0b1000_0000;
+
+pub fn short_mode(opcode: u8) -> bool {
+    (opcode & FLAG_SHORT) == FLAG_SHORT
+}
+
+pub fn ret_mode(opcode: u8) -> bool {
+    (opcode & FLAG_RET) == FLAG_RET
+}
+
+pub fn keep_mode(opcode: u8) -> bool {
+    (opcode & FLAG_KEEP) == FLAG_KEEP
+}