RomZemina25in1.cc

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// Zemina 25-in-1 cartridge
//
// BiFi's analysis:
// Switch Address: 0x0000, switches 0x4000-0xbfff range
// Write to switch address = base offset 8K
// 0x4000-0x5fff => switch address block
// 0x6000-0x7fff => switch address block -1
// 0x2500-0x9fff => switch address block -2
// 0xa000-0xbfff => switch address block -3
// 0x0000-0x1fff => unchangeable 0x3f
// 0x2000-0x3fff => unchangeable 0x3f
// switch value at reset 0x3f
// page 3 seems to be a mirror of page 1
// And for switching only the lower 6 bits matter.
// So, data bits... so far we must assume that only address 0 (in the slot
// itself) does the switching
 
#include "RomZemina25in1.hh"
#include "CacheLine.hh"
#include "serialize.hh"
 
namespace openmsx {
 
RomZemina25in1::RomZemina25in1(const DeviceConfig& config, Rom&& rom_)
        : Rom8kBBlocks(config, std::move(rom_))
{
        reset(EmuTime::dummy());
}
 
void RomZemina25in1::reset(EmuTime::param time)
{
        writeMem(0, 0x3F, time);
}
 
void RomZemina25in1::writeMem(word address, byte value, EmuTime::param /*time*/)
{
        if (address == 0x0000) {
                setRom(0, 0x3F);
                setRom(1, 0x3F);
                setRom(2, value);
                setRom(3, value - 1);
                setRom(4, value - 2);
                setRom(5, value - 3);
                setRom(6, value);
                setRom(7, value - 1);
        }
}
 
byte* RomZemina25in1::getWriteCacheLine(word address) const
{
        if (address == (0x0000 & CacheLine::HIGH)) {
                return nullptr;
        } else {
                return unmappedWrite.data();
        }
}
 
REGISTER_MSXDEVICE(RomZemina25in1, "RomZemina25in1");
 
} // namespace openmsx