setup getters and setters for combined registers

cpu/cpu.go

@@ -4,26 +4,67 @@ import (
 	"radu.macocian.me/goboy/memory"
 )
 
-type cpu_struct struct {
-	A  int8
-	F  int8
-	B  int8
-	C  int8
-	D  int8
-	E  int8
-	H  int8
-	L  int8
-	IR int8
-	IE int8
+type CPU_struct struct {
+	A  byte
+	F  byte
+	B  byte
+	C  byte
+	D  byte
+	E  byte
+	H  byte
+	L  byte
+	IR byte
+	IE byte
 
-	PC int16
-	SP int16
+	PC uint16
+	SP uint16
 }
 
-var cpu = new(cpu_struct)
+var cpu = new(CPU_struct)
 
-func Execute(addr int) {
-	instr := memory.Read(addr + int(cpu.PC))
+func Execute(addr uint) {
+	instr := memory.Read(addr + uint(cpu.PC))
 	cpu.PC++
 	print(string(instr))
 }
+
+func readDoubleRegis(r1 byte, r2 byte) uint16 {
+	return uint16(r1)<<8 | uint16(r2)
+}
+
+func setDoubleRegis(r1 *byte, r2 *byte, value uint16) {
+	*r1 = byte((value & 0xFF00) >> 8)
+	*r2 = byte(value & 0x00FF)
+}
+
+func (cpu *CPU_struct) AF() uint16 {
+	return readDoubleRegis(cpu.A, cpu.F)
+}
+
+func (cpu *CPU_struct) SetAF(value uint16) {
+	setDoubleRegis(&cpu.A, &cpu.F, value)
+}
+
+func (cpu *CPU_struct) BC() uint16 {
+	return readDoubleRegis(cpu.B, cpu.C)
+}
+
+func (cpu *CPU_struct) SetBC(value uint16) {
+	setDoubleRegis(&cpu.B, &cpu.C, value)
+}
+
+func (cpu *CPU_struct) DE() uint16 {
+	return readDoubleRegis(cpu.D, cpu.E)
+}
+
+func (cpu *CPU_struct) SetDE(value uint16) {
+	setDoubleRegis(&cpu.D, &cpu.E, value)
+}
+
+func (cpu *CPU_struct) HL() uint16 {
+	return readDoubleRegis(cpu.H, cpu.L)
+}
+
+func (cpu *CPU_struct) SetHL(value uint16) {
+	setDoubleRegis(&cpu.H, &cpu.L, value)
+}

cpu/cpu_test.go

@@ -0,0 +1,46 @@
+package cpu
+
+import (
+	"testing"
+)
+
+func TestCPUAF(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.A = 0x0A
+	cpu.F = 0x0B
+
+	expected := uint16(0x0A0B)
+	actual := cpu.AF()
+
+	if actual != expected {
+		t.Errorf("actual %x != expected %x", actual, expected)
+	}
+}
+
+func TestCPU_struct_SetAF(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.SetAF(0xABCD)
+
+	expectedA := uint8(0xAB)
+	expectedF := uint8(0xCD)
+	actualA := cpu.A
+	actualF := cpu.F
+	if actualA != expectedA {
+		t.Errorf("actual %x != expected %x", actualA, expectedA)
+	}
+	if actualF != expectedF {
+		t.Errorf("actual %x != expected %x", actualF, expectedF)
+	}
+}
+
+func TestCPU_struct_GetAndSetAF(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.SetAF(0xABCD)
+
+	expectedAF := uint16(0xABCD)
+	actualAF := cpu.AF()
+
+	if actualAF != expectedAF {
+		t.Errorf("actual %x != expected %x", actualAF, expectedAF)
+	}
+}

journal/Day 2 - 2025.04.19.md

@@ -0,0 +1,8 @@
+# For the day:
+- Setup registers reads and writes
+
+# Conclusion
+- Can read and write to combined registers
+- Using a private function in the cpu to work with combined registers
+- Have named functions for the used combined registers for ease of use
+- Added unit tests for the combined registers

journal/References.md

@@ -0,0 +1 @@
+[Opcodes Table](https://meganesulli.com/blog/game-boy-opcodes/)

memory/memory.go

@@ -6,30 +6,30 @@ import (
 
 var memory = new([64000]byte)
 
-func Read(addr int) []byte {
+func Read(addr uint) []byte {
 	checkInside(addr)
 	checkInside(addr + 8)
 
 	return memory[addr : addr+9]
 }
 
-func Write(addr int, val [8]byte) {
+func Write(addr uint, val [8]byte) {
 	checkInside(addr)
 	for i := 0; i < 8; i++ {
-		memory[addr+i] = val[i]
+		memory[int(addr)+i] = val[i]
 	}
 }
 
-func WriteAll(addr int, val []byte) {
+func WriteAll(addr uint, val []byte) {
 	checkInside(addr)
-	checkInside(addr + len(val))
+	checkInside(addr + uint(len(val)))
 	for b := 0; b < len(val); b++ {
-		memory[addr+b] = val[b]
+		memory[int(addr)+b] = val[b]
 	}
 }
 
-func checkInside(addr int) {
-	if addr < 0 || addr >= len(memory) {
+func checkInside(addr uint) {
+	if addr < 0 || addr >= uint(len(memory)) {
 		panic(errorHandling.OutOfMemoryBoundsError)
 	}
 }