added half carry flags

cpu/operations/read_byte.go

@@ -0,0 +1,10 @@
+package operations
+
+func GetLowerByte(value uint16) byte {
+	return (byte)(value)
+}
+
+func GetHigherByte(value uint16) byte {
+	return (byte)(value >> 8)
+}
+

cpu/operations/read_byte_test.go

@@ -0,0 +1,25 @@
+package operations
+
+import (
+	"testing"
+)
+
+func TestReadLowerByte(t *testing.T) {
+	SP := uint16(0x1234)
+
+	actual := GetLowerByte(SP)
+
+	if actual != 0x34 {
+		t.Errorf("actual %v != expected %v", actual, true)
+	}
+}
+
+func TestReadUpperByte(t *testing.T) {
+	SP := uint16(0x1234)
+
+	actual := GetHigherByte(SP)
+
+	if actual != 0x12 {
+		t.Errorf("actual %v != expected %v", actual, true)
+	}
+}