mirror of
https://github.com/ivanizag/izapple2.git
synced 2024-10-31 20:09:02 +00:00
223 lines
6.6 KiB
Go
223 lines
6.6 KiB
Go
package izapple2
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import (
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"errors"
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"fmt"
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"strconv"
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"time"
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)
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/*
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No slot clock with DS1216 Phantom Time Chip for ROM
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See:
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- http://ctrl.pomme.reset.free.fr/index.php/hardware/no-slot-clock-ds1216e/
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- http://ctrl.pomme.reset.free.fr/wp-content/uploads/NSC/DS1216.pdf
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- https://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Chips/SMT%20No-Slot%20Clock/
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- https://www.digchip.com/datasheets/parts/datasheet/000/DS1215-pdf.php
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Test software:
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- http://ctrl.pomme.reset.free.fr/wp-content/uploads/NSC/NSC_UTILITIES_V14.dsk
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Following the spirit of a phantom chip, the DS1215 will replace a memoryHandler do its things and
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delegate to the replaced memoryHandler when needed.
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On the Apple IIe it is usually installed under the ROM CD (under CF on later models). Similar for the Apple IIc.
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It is usually not compatible with the ROMs of the Apple II+, but could be installed in a card with 28 pins ROM,
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working on different addresses. We will install it under the main ROM for all models or under a card ROM.
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Actually software looks like it uses: 0xCs00, 0xCs01 and 0xCs04, usually slot 3
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*/
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type noSlotClockDS1216 struct {
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memory memoryHandler
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state uint8
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index uint8
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timeCapture uint64
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}
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var nscBitPattern = [64]bool{
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true, false, true, false, false, false, true, true, //C5
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false, true, false, true, true, true, false, false, //3A
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true, true, false, false, false, true, false, true, //A3
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false, false, true, true, true, false, true, false, //5C
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true, false, true, false, false, false, true, true, //C5
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false, true, false, true, true, true, false, false, //3A
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true, true, false, false, false, true, false, true, //A3
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false, false, true, true, true, false, true, false, //5C
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}
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const (
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nscStateDisabled = uint8(0)
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nscStatePattern = uint8(1)
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nscStateEnabled = uint8(2)
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)
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func newNoSlotClockDS1216(a *Apple2, memory memoryHandler) *noSlotClockDS1216 {
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var nsc noSlotClockDS1216
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nsc.memory = memory
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nsc.state = nscStateDisabled
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nsc.index = 0
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return &nsc
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}
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func (nsc *noSlotClockDS1216) peek(address uint16) uint8 {
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read := (address & 0x04) != 0 // Bit A2 of the address bus
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value := (address & 0x01) != 0 // Bit A0 of the address bus
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var data uint8
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switch nsc.state {
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case nscStateDisabled:
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if read {
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// Prior to executing the first of 64 write cycles, a read cycle should be executed
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// by holding A2 high. The read cycle will reset the comparison register pointer
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// within the SmartWatch, ensuring the pattern recognition starts with the first
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// bit of the sequence.
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nsc.state = nscStatePattern
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nsc.index = 0
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}
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data = nsc.memory.peek(address)
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case nscStatePattern:
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// Communication with the SmartWatch is established by pattern recognition of a serial
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// bit stream of 64 bits that must be matched by executing 64 consecutive write cycles,
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// placing address bit A2 low with the proper data on address bit A0. The 64 write cycles
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// are used only to gain access to the SmartWatch.
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if read {
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// If a read cycle occurs at any time during pattern recognition, the present
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// sequence is aborted and the comparison register pointer is reset.
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nsc.index = 0
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} else {
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// When the first write cycle is executed, it is compared to bit 0 of the 64-bit
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// comparison register. Pattern recognition continues for a total of 64 write cycles
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// until all the bits in the comparison register have been matched.
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if value == nscBitPattern[nsc.index] {
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// If a match is found, the pointer increments to the next location of the
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// comparison register and awaits the next write cycle.
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nsc.index++
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if nsc.index == 64 {
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// With a correct match for 64 bits, the SmartWatch is enabled and data transfer to or
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// from the timekeeping registers can proceed.
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nsc.state = nscStateEnabled
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nsc.index = 0
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nsc.loadTime()
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}
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} else {
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// If a match is not found, the pointer does not advance and all subsequent write
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// cycles are ignored.
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nsc.state = nscStateDisabled
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}
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}
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data = nsc.memory.peek(address)
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case nscStateEnabled:
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// The next 64 cycles will cause the SmartWatch to either receive data on data in (A0) or
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// transmit data on data out (DQ0), depending on the level of /WRITE READ (A2).
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if read {
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// Get info
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data = uint8(nsc.timeCapture>>nsc.index) & 1
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// The info is set on the LSB. The rest of bits are zero. Should they be the value in ROM?
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} else {
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// Store info
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if value {
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nsc.timeCapture |= (1 << nsc.index)
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} else {
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nsc.timeCapture &= ^(1 << nsc.index)
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}
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data = 0 // What is returned on write?
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}
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nsc.index++
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if nsc.index == 64 {
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// Is this right?
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nsc.state = nscStateDisabled
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nsc.index = 0
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}
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}
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return data
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}
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func (nsc *noSlotClockDS1216) poke(address uint16, value uint8) {
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nsc.memory.poke(address, value)
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}
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func (nsc *noSlotClockDS1216) setBase(base uint16) {
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nsc.memory.setBase(base)
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}
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func (nsc *noSlotClockDS1216) loadTime() {
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now := time.Now()
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var register uint64
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year := uint64(now.Year()) % 100
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register = year / 10
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register <<= 4
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register += year % 10
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register <<= 4
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month := uint64(now.Month())
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register += month / 10
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register <<= 4
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register += month % 10
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register <<= 4
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day := uint64(now.Day())
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register += day / 10
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register <<= 4
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register += day % 10
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register <<= 4
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// Bits 4 and 5 of the day register are used to control the RST and oscillator
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// functions. These bits are shipped from the factory set to logic 1.
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register += 0x0 //0x3, but zero on read.
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register <<= 4
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register += uint64(now.Weekday()) + 1
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register <<= 4
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hour := uint64(now.Hour())
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register += 0x0 // 0x8 for 24 hour mode, but zero on read.
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register += hour / 10
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register <<= 4
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register += hour % 10
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register <<= 4
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minute := uint64(now.Minute())
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register += minute / 10
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register <<= 4
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register += minute % 10
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register <<= 4
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second := uint64(now.Second())
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register += second / 10
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register <<= 4
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register += second % 10
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register <<= 4
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centisecond := uint64(now.Nanosecond() / 10000000)
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register += centisecond / 10
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register <<= 4
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register += centisecond % 10
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nsc.timeCapture = register
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}
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func setupNoSlotClock(a *Apple2, arg string) error {
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if arg == "main" {
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nsc := newNoSlotClockDS1216(a, a.mmu.physicalROM)
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a.mmu.physicalROM = nsc
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} else {
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slot, err := strconv.ParseUint(arg, 10, 8)
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if err != nil || slot < 1 || slot > 7 {
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return errors.New("invalid slot for the no slot clock, use 'none', 'main' or a slot number from 1 to 7")
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}
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cardRom := a.mmu.cardsROM[slot]
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if cardRom == nil {
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return fmt.Errorf("no ROM available on slot %d to add a no slot clock", slot)
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}
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nsc := newNoSlotClockDS1216(a, cardRom)
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a.mmu.cardsROM[slot] = nsc
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}
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return nil
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}
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