package apple2 import ( "encoding/binary" "fmt" "io" ) type ioC0Page struct { softSwitchesR [256]softSwitchR softSwitchesW [256]softSwitchW softSwitchesData [128]uint8 keyboard KeyboardProvider speaker SpeakerProvider apple2 *Apple2 } type softSwitchR func(io *ioC0Page) uint8 type softSwitchW func(io *ioC0Page, value uint8) // KeyboardProvider declares the keyboard implementation requirements type KeyboardProvider interface { GetKey(strobe bool) (key uint8, ok bool) } // SpeakerProvider declares the speaker implementation requirements type SpeakerProvider interface { // Click receives a speaker click. The argument is the CPU cycle when it is generated Click(cycle uint64) } // See https://www.kreativekorp.com/miscpages/a2info/iomemory.shtml // See https://stason.org/TULARC/pc/apple2/programmer/004-I-d-like-to-do-some-serious-Apple-II-programming-Whe.html const ( ssOn uint8 = 0x80 ssOff uint8 = 0x00 ) func newIoC0Page(a *Apple2) *ioC0Page { var io ioC0Page io.apple2 = a addApple2SoftSwitches(&io) if a.isApple2e { addApple2ESoftSwitches(&io) } return &io } func (p *ioC0Page) save(w io.Writer) { binary.Write(w, binary.BigEndian, p.softSwitchesData) } func (p *ioC0Page) load(r io.Reader) { binary.Read(r, binary.BigEndian, &p.softSwitchesData) } func (p *ioC0Page) addSoftSwitchRW(address uint8, ss softSwitchR) { p.addSoftSwitchR(address, ss) p.addSoftSwitchW(address, func(p *ioC0Page, _ uint8) { ss(p) }) } func (p *ioC0Page) addSoftSwitchR(address uint8, ss softSwitchR) { if p.softSwitchesR[address] != nil { fmt.Printf("Addresss 0x0c%02x is already assigned for read", address) } p.softSwitchesR[address] = ss } func (p *ioC0Page) addSoftSwitchW(address uint8, ss softSwitchW) { if p.softSwitchesW[address] != nil { fmt.Printf("Addresss 0x0c%02x is already assigned for write", address) } p.softSwitchesW[address] = ss } func (p *ioC0Page) isSoftSwitchActive(ioFlag uint8) bool { return (p.softSwitchesData[ioFlag] & ssOn) == ssOn } func (p *ioC0Page) setKeyboardProvider(kb KeyboardProvider) { p.keyboard = kb } func (p *ioC0Page) setSpeakerProvider(s SpeakerProvider) { p.speaker = s } func (p *ioC0Page) peek(address uint16) uint8 { //fmt.Printf("Peek on $%02x\n", address) pageAddress := uint8(address) ss := p.softSwitchesR[pageAddress] if ss == nil { if p.apple2.panicSS { panic(fmt.Sprintf("Unknown softswitch on read to 0xC0%02x", pageAddress)) } return 0 } return ss(p) } func (p *ioC0Page) poke(address uint16, value uint8) { //fmt.Printf("Poke on $%02x with %02x\n", address, value) pageAddress := uint8(address) ss := p.softSwitchesW[pageAddress] if ss == nil { if p.apple2.panicSS { panic(fmt.Sprintf("Unknown softswitch on write to 0xC0%02x", pageAddress)) } return } ss(p, value) }