add jmp, jz

src/cpu.rs

@@ -18,7 +18,7 @@ pub struct CPU{
 }
 
 impl CPU {
-    pub fn inc_cp(&mut self) {
+    pub fn inc_pc(&mut self) {
         self.pc += 1;
     }
 
@@ -27,8 +27,8 @@ impl CPU {
     }
 
     pub fn mov(&mut self, mem: &mut Memory) {
-        let reg = mem.read(self.pc); self.inc_cp();
+        let reg = mem.read(self.pc); self.inc_pc();
-        let val = mem.read(self.pc); self.inc_cp();
+        let val = mem.read(self.pc); self.inc_pc();
 
         match reg {
             0 => self.a = val,
@@ -132,4 +132,25 @@ impl CPU {
         self.carry = borrow;
     }
 
+    pub fn jmp(&mut self, mem: &mut Memory) {
+        let low = mem.read(self.pc) as u16; self.inc_pc();
+        let high = mem.read(self.pc) as u16; self.inc_pc();
+
+        let addrs = (high << 8) | low;
+
+        self.pc = addrs;
+    }
+
+    pub fn jz(&mut self, mem: &mut Memory) {
+        let low = mem.read(self.pc) as u16; self.inc_pc();
+        let high = mem.read(self.pc) as u16; self.inc_pc();
+
+        let addrs = (high << 8) | low;
+
+        if self.zero {
+            self.pc = addrs;
+        }
+
+    }
+
 }

src/main.rs

@@ -20,31 +20,36 @@ fn main() {
     // b = 2
     mem.write(0x0003, Instruction::MOV as u8);
     mem.write(0x0004, 1);
-    mem.write(0x0005, 1);
+    mem.write(0x0005, 5);
 
     // a = a + b
     mem.write(0x0006, Instruction::SUB as u8);
     mem.write(0x0007, 0);
     mem.write(0x0008, 1);
 
+    // JMP to halt
+    mem.write(0x0009, Instruction::JZ as u8);
+    mem.write(0x000a, 0x0f); // Low
+    mem.write(0x000b, 0x00); // High
+
     // set b = 0
-    mem.write(0x0009, Instruction::MOV as u8);
+    mem.write(0x000c, Instruction::MOV as u8);
-    mem.write(0x000a, 1);
+    mem.write(0x000d, 1);
-    mem.write(0x000b, 0);
+    mem.write(0x000e, 0);
 
     // halt
-    mem.write(0x000c, Instruction::HLT as u8);
+    mem.write(0x000f, Instruction::HLT as u8);
 
     while !cpu.halted {
         let opcode = mem.read(cpu.pc);
-        cpu.inc_cp();
+        cpu.inc_pc();
 
         match opcode {
             x if x == Instruction::MOV as u8 =>  cpu.mov(&mut mem),
             x if x == Instruction::ADD as u8 => cpu.add(&mut mem),
             x if x == Instruction::SUB as u8 => cpu.sub(&mut mem),
-            x if x == Instruction::JMP as u8 => {}
+            x if x == Instruction::JMP as u8 => cpu.jmp(&mut mem),
-            x if x == Instruction::JZ  as u8 => {}
+            x if x == Instruction::JZ  as u8 => cpu.jz(&mut mem),
             x if x == Instruction::HLT as u8 => cpu.halt(),
             _ => panic!("Unknown opcode {:02X}", opcode),
         }