75 lines
2.1 KiB
Go
75 lines
2.1 KiB
Go
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package apple2
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import "fmt"
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const (
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ioFlagIntCxRom uint8 = 0x15
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ioFlagSlotC3Rom uint8 = 0x17
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)
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func addApple2ESoftSwitches(mmu *memoryManager) {
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ss := &mmu.ioPage.softSwitches
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ss[0x06] = getSoftSwitchExt(ioFlagIntCxRom, 0x00, softSwitchIntCxRomOff)
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ss[0x07] = getSoftSwitchExt(ioFlagIntCxRom, 0x80, softSwitchIntCxRomOn)
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ss[0x15] = getStatusSoftSwitchExt(ioFlagIntCxRom)
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ss[0x0A] = getSoftSwitchExt(ioFlagSlotC3Rom, 0x00, softSwitchSlotC3RomOff)
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ss[0x0B] = getSoftSwitchExt(ioFlagSlotC3Rom, 0x80, softSwitchSlotC3RomOn)
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ss[0x17] = getStatusSoftSwitchExt(ioFlagSlotC3Rom)
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ss[0x1c] = getStatusSoftSwitchExt(ioFlagSecondPage)
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}
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type softSwitchExtAction func(io *ioC0Page)
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func getStatusSoftSwitchExt(ioFlag uint8) softSwitch {
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return func(io *ioC0Page, isWrite bool, value uint8) uint8 {
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return io.softSwitchesData[ioFlag]
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}
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}
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func getSoftSwitchExt(ioFlag uint8, dstValue uint8, action softSwitchExtAction) softSwitch {
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return func(io *ioC0Page, isWrite bool, value uint8) uint8 {
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fmt.Printf("Softswitch 0x%02x %v %v\n", ioFlag, isWrite, dstValue)
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if !isWrite {
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return 0 // Ignore reads
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}
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currentValue := io.softSwitchesData[ioFlag]
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if currentValue == dstValue {
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return 0 // Already switched, ignore
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}
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action(io)
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io.softSwitchesData[ioFlag] = value
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return 0
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}
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}
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func softSwitchIntCxRomOn(io *ioC0Page) {
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for i := uint8(1); i < 16; i++ {
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io.mmu.activeMemory.SetPage(uint8(0xc0+i), &io.mmu.physicalROMe[i])
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}
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}
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func softSwitchIntCxRomOff(io *ioC0Page) {
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// TODO restore all the ROM from the slot for 0xc1 to 0xc7
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for i := 1; i <= 16; i++ {
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io.mmu.activeMemory.SetPage(uint8(0xc0+i), &io.mmu.unassignedExpansionROM[i])
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}
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}
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func softSwitchSlotC3RomOn(io *ioC0Page) {
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if io.isSoftSwitchExtActive(ioFlagIntCxRom) {
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return // Ignore if allt the Apple2 shadow ROM is active
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}
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// TODO restore the slot 3 ROM
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io.mmu.activeMemory.SetPage(0xC3, &io.mmu.unassignedExpansionROM[3])
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}
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func softSwitchSlotC3RomOff(io *ioC0Page) {
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if io.isSoftSwitchExtActive(ioFlagIntCxRom) {
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return // Ignore if allt the Apple2 shadow ROM is active
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}
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io.mmu.activeMemory.SetPage(0xC3, &io.mmu.physicalROMe[3])
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}
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