move pc increment to CPU.step

pcasaretto · Apr 7, 2024 · f407b17 · f407b17
1 parent 87e7f90
commit f407b17
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Showing 7 changed files with 29 additions and 84 deletions.
diff --git a/src/instructions/adc.rs b/src/instructions/adc.rs
@@ -14,8 +14,6 @@ pub fn adc(target: RegisterTarget) -> impl Fn(&mut CPU) {
         cpu.registers.f.subtract = false;
         cpu.registers.f.zero = new_value == 0;
         cpu.registers.f.half_carry = (current_value & 0xF) + (target_value & 0xF) > 0xF;
-
-        cpu.pc = cpu.pc.wrapping_add(1);
     }
 }
 
@@ -133,24 +131,4 @@ mod tests {
         adc(RegisterTarget::C)(&mut cpu);
         assert!(cpu.registers.f.half_carry);
     }
-
-    #[test]
-    fn test_adc_advance_pc() {
-        let mut cpu = CPU {
-            pc: 123,
-            ..Default::default()
-        };
-        adc(RegisterTarget::C)(&mut cpu);
-        assert_eq!(cpu.pc, 124);
-    }
-
-    #[test]
-    fn test_adc_advance_pc_wrap() {
-        let mut cpu = CPU {
-            pc: 0xFFFF,
-            ..Default::default()
-        };
-        adc(RegisterTarget::C)(&mut cpu);
-        assert_eq!(cpu.pc, 0);
-    }
 }
diff --git a/src/instructions/add.rs b/src/instructions/add.rs
@@ -11,8 +11,6 @@ pub fn add(target: RegisterTarget) -> impl Fn(&mut CPU) {
         cpu.registers.f.zero = new_value == 0;
         cpu.registers.f.subtract = false;
         cpu.registers.f.half_carry = (current_value & 0xF) + (target_value & 0xF) > 0xF;
-
-        cpu.pc = cpu.pc.wrapping_add(1);
     }
 }
 
@@ -112,24 +110,4 @@ mod tests {
         add(RegisterTarget::C)(&mut cpu);
         assert!(cpu.registers.f.half_carry);
     }
-
-    #[test]
-    fn test_add_advance_pc() {
-        let mut cpu = CPU {
-            pc: 123,
-            ..Default::default()
-        };
-        add(RegisterTarget::C)(&mut cpu);
-        assert_eq!(cpu.pc, 124);
-    }
-
-    #[test]
-    fn test_add_advance_pc_wrap() {
-        let mut cpu = CPU {
-            pc: 0xFFFF,
-            ..Default::default()
-        };
-        add(RegisterTarget::C)(&mut cpu);
-        assert_eq!(cpu.pc, 0);
-    }
 }
diff --git a/src/instructions/inc.rs b/src/instructions/inc.rs
@@ -1,32 +1,10 @@
 use crate::CPU;
 
 pub fn inc_sp() -> impl Fn(&mut CPU) {
-    move |cpu: &mut CPU| {
-        cpu.pc = cpu.pc.wrapping_add(1);
-    }
+    move |_: &mut CPU| {}
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-
-    #[test]
-    fn test_inc_sp() {
-        let mut cpu = CPU {
-            pc: 0xF012,
-            ..Default::default()
-        };
-        inc_sp()(&mut cpu);
-        assert_eq!(cpu.pc, 0xF013);
-    }
-
-    #[test]
-    fn test_inc_sp_wrap() {
-        let mut cpu = CPU {
-            pc: 0xFFFF,
-            ..Default::default()
-        };
-        inc_sp()(&mut cpu);
-        assert_eq!(cpu.pc, 0x0000);
-    }
 }
diff --git a/src/instructions/ld.rs b/src/instructions/ld.rs
@@ -5,23 +5,32 @@ pub fn ld_d16_u16(reg: Register16bTarget) -> impl Fn(&mut CPU) {
         let low = cpu.bus.memory[(cpu.pc + 1) as usize];
         let high = cpu.bus.memory[(cpu.pc + 2) as usize];
         cpu.registers.set_u16(reg, u16::from_le_bytes([low, high]));
-        cpu.pc += 3;
+        cpu.pc = cpu.pc.wrapping_add(2);
     }
 }
 
 pub fn ld_d8_u8(reg: RegisterTarget) -> impl Fn(&mut CPU) {
     move |cpu: &mut CPU| {
         let value = cpu.bus.memory[(cpu.pc + 1) as usize];
         cpu.registers.set_u8(reg, value);
-        cpu.pc += 2;
+        cpu.pc = cpu.pc.wrapping_add(1);
     }
 }
 
 pub fn ld_r_r(src: RegisterTarget, dest: RegisterTarget) -> impl Fn(&mut CPU) {
     move |cpu: &mut CPU| {
         let value = cpu.registers.get_u8(src);
         cpu.registers.set_u8(dest, value);
-        cpu.pc += 1;
+    }
+}
+
+pub fn ld_hl_inc() -> impl Fn(&mut CPU) {
+    move |cpu: &mut CPU| {
+        let hl = cpu.registers.get_u16(Register16bTarget::HL);
+        let value = cpu.bus.memory[hl as usize];
+        cpu.registers.set_u8(RegisterTarget::A, value);
+        cpu.registers
+            .set_u16(Register16bTarget::HL, hl.wrapping_add(1));
     }
 }
 
@@ -37,7 +46,7 @@ mod tests {
         cpu.bus.memory[2] = 0x02;
         ld_d16_u16(Register16bTarget::BC)(&mut cpu);
         assert_eq!(cpu.registers.get_u16(Register16bTarget::BC), 0x0201);
-        assert_eq!(cpu.pc, 3);
+        assert_eq!(cpu.pc, 2);
     }
 
     #[test]
@@ -52,7 +61,6 @@ mod tests {
         };
         ld_r_r(RegisterTarget::B, RegisterTarget::A)(&mut cpu);
         assert_eq!(cpu.registers.get_u8(RegisterTarget::A), 0x01);
-        assert_eq!(cpu.pc, 1);
     }
 
     #[test]
@@ -61,6 +69,16 @@ mod tests {
         cpu.bus.memory[1] = 0x01;
         ld_d8_u8(RegisterTarget::B)(&mut cpu);
         assert_eq!(cpu.registers.get_u8(RegisterTarget::B), 0x01);
-        assert_eq!(cpu.pc, 2);
+        assert_eq!(cpu.pc, 1);
+    }
+
+    #[test]
+    fn test_ld_hl_inc() {
+        let mut cpu = CPU::default();
+        cpu.registers.set_u16(Register16bTarget::HL, 0x1000);
+        cpu.bus.memory[0x1000] = 0x01;
+        ld_hl_inc()(&mut cpu);
+        assert_eq!(cpu.registers.get_u8(RegisterTarget::A), 0x01);
+        assert_eq!(cpu.registers.get_u16(Register16bTarget::HL), 0x1001);
     }
 }
diff --git a/src/instructions/mod.rs b/src/instructions/mod.rs
@@ -20,7 +20,8 @@ pub fn from_byte(byte: u8) -> Box<dyn Fn(&mut CPU)> {
         0x01 => Box::new(ld::ld_d16_u16(Register16bTarget::BC)),
         0x11 => Box::new(ld::ld_d16_u16(Register16bTarget::DE)),
         0x21 => Box::new(ld::ld_d16_u16(Register16bTarget::HL)),
-        0x33 => Box::new(inc::inc_sp()),
+        0x2A => Box::new(ld::ld_hl_inc()),
+        // 0x33 => Box::new(inc::inc_sp()),
         0x40 => Box::new(ld::ld_r_r(RegisterTarget::B, RegisterTarget::B)),
         0x41 => Box::new(ld::ld_r_r(RegisterTarget::B, RegisterTarget::C)),
         0x42 => Box::new(ld::ld_r_r(RegisterTarget::B, RegisterTarget::D)),

diff --git a/src/instructions/nop.rs b/src/instructions/nop.rs
@@ -1,19 +1,10 @@
 use super::super::*;
 
 pub fn nop() -> impl Fn(&mut CPU) {
-    move |cpu: &mut CPU| {
-        cpu.pc += 1;
-    }
+    move |_: &mut CPU| {}
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
-
-    #[test]
-    fn test_nop() {
-        let mut cpu = CPU::default();
-        nop()(&mut cpu);
-        assert_eq!(cpu.pc, 1);
-    }
 }
diff --git a/src/lib.rs b/src/lib.rs
@@ -152,6 +152,7 @@ impl Default for CPU {
 impl CPU {
     pub fn step(&mut self) {
         let instruction_byte = self.bus.read_byte(self.pc);
+        self.pc = self.pc.wrapping_add(1);
         let instruction = instructions::from_byte(instruction_byte);
         instruction(self)
     }