protected void writeAddress(byte val) {
/* >8C02, address write */
if (vdpaddrflag) {
vdpaddr = (vdpaddr & 0xff) | (val << 8);
} else {
vdpaddr = (vdpaddr & 0xff00) | (val & 0xff);
}
if ((vdpaddrflag = !vdpaddrflag) == false) {
if (dumpVdpAccess.getBoolean()) {
PrintWriter pw = Logging.getLog(dumpFullInstructions);
if (pw != null) pw.println("Address: " + HexUtils.toHex4(vdpaddr));
}
if ((vdpaddr & 0x8000) != 0) {
writeRegAddr(vdpaddr);
vdpaddr &= 0x3fff;
} else if ((vdpaddr & 0x4000) != 0) {
vdpaddr &= 0x3fff;
} else {
// read ahead one byte
vdpreadahead = videoMemory.readByte(vdpaddr);
autoIncrementAddr();
}
}
}
protected byte readData() {
/* >8800, memory read */
byte ret;
ret = vdpreadahead;
vdpreadahead = videoMemory.readByte(vdpaddr);
autoIncrementAddr();
return ret;
}
/** @param machine */
public Vdp9918AMmio(ISettingsHandler settings, IMemory memory, IVdpChip vdp, int memorySize) {
super(new VdpRamArea(memorySize));
this.settings = settings;
dumpFullInstructions = settings.get(ICpu.settingDumpFullInstructions);
dumpVdpAccess = settings.get(IVdpChip.settingDumpVdpAccess);
this.videoMemory = vdp.getVideoMemory();
videoMemory.setSize(memorySize);
initMemory(memory, memorySize);
((VdpTMS9918A) vdp).setVdpMmio(this);
setVdpHandler(vdp);
}
protected void writeData(byte val) {
/* >8C00, data write */
/* this flag is used to verify that the VDP
address was written as >4000 + vdpaddr.
If not, then writing to it functions as
a read-before-write. */
vdpaddrflag = false;
// byte oldval = videoMemory.flatReadByte(vdpaddr);
videoMemory.writeByte(vdpaddr, val);
if ((vdpaddr & 0xf) == 0 && dumpVdpAccess.getBoolean()) {
PrintWriter pw = Logging.getLog(dumpFullInstructions);
if (pw != null) pw.println("Address: " + HexUtils.toHex4(vdpaddr));
}
autoIncrementAddr();
vdpreadahead = val;
}