izapple2/registers.go

package main

const (
	regA  = 0
	regX  = 1
	regY  = 2
	regP  = 4
	regSP = 5
	regPC = 6 // 2 bytes
)

type registers struct {
	data [8]uint8
}

func (r *registers) getRegister(i int) uint8 { return r.data[i] }

func (r *registers) getA() uint8  { return r.data[regA] }
func (r *registers) getX() uint8  { return r.data[regX] }
func (r *registers) getY() uint8  { return r.data[regY] }
func (r *registers) getP() uint8  { return r.data[regP] }
func (r *registers) getSP() uint8 { return r.data[regSP] }

func (r *registers) setRegister(i int, v uint8) {
	r.data[i] = v
}
func (r *registers) setA(v uint8)  { r.setRegister(regA, v) }
func (r *registers) setX(v uint8)  { r.setRegister(regX, v) }
func (r *registers) setY(v uint8)  { r.setRegister(regY, v) }
func (r *registers) setP(v uint8)  { r.setRegister(regP, v) }
func (r *registers) setSP(v uint8) { r.setRegister(regSP, v) }

func (r *registers) getPC() uint16 {
	return uint16(r.data[regPC])*256 + uint16(r.data[regPC+1])
}

func (r *registers) setPC(v uint16) {
	r.data[regPC] = uint8(v >> 8)
	r.data[regPC+1] = uint8(v)
}