package goapple2 import ( "fmt" "github.com/zellyn/go6502/cpu" "github.com/zellyn/goapple2/cards" "github.com/zellyn/goapple2/videoscan" ) // Memory for the tests. Satisfies the cpu.Memory interface. type Apple2 struct { mem [65536]byte cpu cpu.Cpu key byte // BUG(zellyn): make reads/writes atomic keys chan byte plotter videoscan.Plotter scanner *videoscan.Scanner Done bool lastRead byte cards [8]cards.Card "Peripheral cards" cardMask byte cardRomMask byte cardRomConflict bool "True if more than one card is handling the 2k ROM area" cardRomHandler byte card12kMask byte card12kConflict bool "True if more than one card is handling the 12k ROM area" card12kHandler byte } func NewApple2(p videoscan.Plotter, rom []byte, charRom [2048]byte) *Apple2 { a2 := Apple2{ // BUG(zellyn): this is not how the apple2 keyboard actually works keys: make(chan byte, 16), } copy(a2.mem[len(a2.mem)-len(rom):len(a2.mem)], rom) a2.scanner = videoscan.NewScanner(&a2, p, charRom) a2.cpu = cpu.NewCPU(&a2, &a2, cpu.VERSION_6502) a2.cpu.Reset() return &a2 } func (a2 *Apple2) AddCard(card cards.Card) error { slot := card.Slot() slotbit := byte(1 << slot) if slotbit&a2.cardMask > 0 { return fmt.Errorf("Slot %d already has a card: %s", slot, a2.cards[slot]) } a2.cardMask |= slotbit a2.cards[slot] = card return nil } func (a2 *Apple2) handleCardRom(address uint16, value byte, write bool) byte { return a2.EmptyRead() } func (a2 *Apple2) handleC00X(address uint16, value byte, write bool) byte { if address < 0xC080 { switch address & 0xC0F0 { // $C00X: Read keyboard case 0xC000: if a2.key&0x80 == 0 { select { case key := <-a2.keys: a2.key = key default: } } return a2.key // $C01X: Reset keyboard case 0xC010: a2.key &= 0x7F return a2.EmptyRead() } switch address { case 0xC050: // GRAPHICS a2.scanner.SetGraphics(true) case 0xC051: // TEXT a2.scanner.SetGraphics(false) case 0xC052: // NOMIX a2.scanner.SetMix(false) case 0xC053: // MIX a2.scanner.SetMix(true) case 0xC054: // PAGE 1 a2.scanner.SetPage(1) case 0xC055: // PAGE 2 a2.scanner.SetPage(2) case 0xC056: // LORES a2.scanner.SetHires(false) case 0xC057: // HIRES a2.scanner.SetHires(true) } } if address < 0xC080 { return a2.EmptyRead() } if address < 0xC100 { slot := byte((address - 0xC080) >> 4) if a2.cards[slot] != nil { if write { a2.cards[slot].Write16(byte(address&0xF), value) return 0 } else { return a2.cards[slot].Read16(byte(address & 0xF)) } } return a2.EmptyRead() } if address < 0xC800 { slot := byte((address - 0xC000) >> 8) if a2.cards[slot] != nil { if write { a2.cards[slot].Write256(byte(address&0xFF), value) return 0 } else { return a2.cards[slot].Read256(byte(address & 0xFF)) } } return a2.EmptyRead() } // 0xCFFF disables 2k on all cards if address == 0xCFFF { for i := 0; a2.cardMask > 0; a2.cardMask >>= 1 { if a2.cardMask&1 > 0 { a2.cards[i].ROMDisabled() } i++ } return a2.EmptyRead() } // Only addresses left are 0xC800-0xCFFE if a2.cardRomMask == 0 { return a2.EmptyRead() } if a2.cardRomConflict { panic(fmt.Sprintf("More than one card trying to provide 2K ROM: Mask=$%02X", a2.cardRomMask)) } if write { a2.cards[a2.cardRomHandler].Write(address, value) return 0 } return a2.cards[a2.cardRomHandler].Read(address) } // EmptyRead returns the value last read from RAM, lingering on the bus. func (a2 *Apple2) EmptyRead() byte { return a2.lastRead } func (a2 *Apple2) Read(address uint16) byte { if address&0xF000 == 0xC000 { return a2.handleC00X(address, 0, false) } if address >= 0xD000 && a2.cardRomMask > 0 { if a2.card12kConflict { panic(fmt.Sprintf("More than one card trying to provide 12K ROM: Mask=$%02X", a2.card12kMask)) } a2.lastRead = a2.cards[a2.card12kHandler].Read(address) return a2.lastRead } a2.lastRead = a2.mem[address] return a2.lastRead } func (a2 *Apple2) RamRead(address uint16) byte { a2.lastRead = a2.mem[address] return a2.lastRead } func (a2 *Apple2) Write(address uint16, value byte) { if address >= 0xD000 { if a2.cardRomMask > 0 { if a2.card12kConflict { panic(fmt.Sprintf("More than one card trying to provide 12K ROM: Mask=$%02X", a2.card12kMask)) } a2.cards[a2.card12kHandler].Write(address, value) } return } if address&0xF000 == 0xC000 { a2.handleC00X(address, value, true) return } a2.mem[address] = value } func (a2 *Apple2) Keypress(key byte) { a2.keys <- key | 0x80 } func (a2 *Apple2) Step() error { return a2.cpu.Step() } func (a2 *Apple2) Tick() { a2.scanner.Scan1() } func (a2 *Apple2) Quit() { a2.Done = true } func (a2 *Apple2) HandleROM(onOff bool, slot byte) { if onOff { a2.cardRomMask |= (1 << slot) a2.cardRomHandler = slot } else { a2.cardRomMask &^= (1 << slot) } a2.cardRomConflict = a2.cardRomMask&(a2.cardRomMask-1) > 0 if !onOff && !a2.cardRomConflict && a2.cardRomMask > 0 { // Removed a card: figure out new handler for i := byte(0); i < 7; i++ { if 1< 0 if !onOff && !a2.card12kConflict && a2.card12kMask > 0 { // Removed a card: figure out new handler for i := byte(0); i < 7; i++ { if 1<