From 7b420e4d183999f2572c7d900338c96573da7384 Mon Sep 17 00:00:00 2001
From: radumacocian <rmacocian@yahoo.com>
Date: Tue, 29 Apr 2025 19:26:46 +0200
Subject: [PATCH] added flag read and set operations and tests

---
 cpu/cpu.go      | 43 +++++++++++++++++++++++++++++++++++++++++++
 cpu/cpu_test.go | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/cpu/cpu.go b/cpu/cpu.go
index 5de7f43..c2c52eb 100644
--- a/cpu/cpu.go
+++ b/cpu/cpu.go
@@ -37,6 +37,18 @@ func setDoubleRegis(r1 *byte, r2 *byte, value uint16) {
 	*r2 = byte(value & 0x00FF)
 }
 
+func readBit(r byte, pos uint8) bool {
+	return r>>pos&1 == 1
+}
+
+func setBit(r *byte, pos uint8, value bool) {
+	if value {
+		*r |= 1 << pos
+		return
+	}
+	*r &= ^(1 << pos)
+}
+
 func (cpu *CPU_struct) AF() uint16 {
 	return readDoubleRegis(cpu.A, cpu.F)
 }
@@ -68,3 +80,34 @@ func (cpu *CPU_struct) HL() uint16 {
 func (cpu *CPU_struct) SetHL(value uint16) {
 	setDoubleRegis(&cpu.H, &cpu.L, value)
 }
+
+func (cpu *CPU_struct) ZF() bool {
+	return readBit(cpu.F, 7)
+}
+
+func (cpu *CPU_struct) SetZF(value bool) {
+	setBit(&cpu.F, 7, value)
+}
+
+func (cpu *CPU_struct) NF() bool {
+	return readBit(cpu.F, 6)
+}
+
+func (cpu *CPU_struct) SetNF(value bool) {
+	setBit(&cpu.F, 6, value)
+}
+func (cpu *CPU_struct) HF() bool {
+	return readBit(cpu.F, 5)
+}
+
+func (cpu *CPU_struct) SetHF(value bool) {
+	setBit(&cpu.F, 5, value)
+}
+
+func (cpu *CPU_struct) CF() bool {
+	return readBit(cpu.F, 4)
+}
+
+func (cpu *CPU_struct) SetCF(value bool) {
+	setBit(&cpu.F, 4, value)
+}
diff --git a/cpu/cpu_test.go b/cpu/cpu_test.go
index 6f2844e..cc1898c 100644
--- a/cpu/cpu_test.go
+++ b/cpu/cpu_test.go
@@ -44,3 +44,39 @@ func TestCPU_struct_GetAndSetAF(t *testing.T) {
 		t.Errorf("actual %x != expected %x", actualAF, expectedAF)
 	}
 }
+
+func TestCPU_struct_SetCY(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.F = 0x00
+
+	cpu.SetCF(true)
+
+	expected := byte(0b00010000)
+	actual := cpu.F
+
+	if actual != expected {
+		t.Errorf("actual %x != expected %x", actual, expected)
+	}
+}
+
+func TestCPU_struct_GetCY(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.F = 0b01011000
+
+	actual := cpu.CF()
+
+	if actual != true {
+		t.Errorf("actual %v != expected %v", actual, true)
+	}
+}
+
+func TestCPU_struct_SetAndGetCY(t *testing.T) {
+	cpu := CPU_struct{}
+	cpu.SetCF(true)
+
+	actual := cpu.CF()
+
+	if actual != true {
+		t.Errorf("actual %v != expected %v", actual, true)
+	}
+}