private byte ReadPort(ushort port)
{
port &= 0xFF;
if (port < 0x40) // General IO ports
{
switch (port)
{
case 0x00: if (stand_alone)
{
return(ReadPort0());
}
else
{
_lagged = false; return(cntr_rd_0);
}
case 0x01: return(Port01);
case 0x02: return(Port02);
case 0x03: return(Port03);
case 0x04: p4_read = true; return(Port04);
case 0x05: return(Port05);
case 0x06: return(0xFF);
case 0x3E: return(Port3E);
default: return(0xFF);
}
}
if (port < 0x80) // VDP Vcounter/HCounter
{
if ((port & 1) == 0)
{
return(Vdp.ReadVLineCounter());
}
else
{
return(Vdp.ReadHLineCounter());
}
}
if (port < 0xC0) // VDP data/control ports
{
if ((port & 1) == 0)
{
return(Vdp.ReadData());
}
else
{
return(Vdp.ReadVdpStatus());
}
}
switch (port)
{
case 0xC0:
case 0xDC: if (stand_alone)
{
return(ReadControls1());
}
else
{
_lagged = false; return(cntr_rd_1);
}
case 0xC1:
case 0xDD: if (stand_alone)
{
return(ReadControls2());
}
else
{
_lagged = false; return(cntr_rd_2);
}
case 0xDE: return(PortDEEnabled ? PortDE : (byte)0xFF);
case 0xF2: return(HasYM2413 ? YM2413.DetectionValue : (byte)0xFF);
default: return(0xFF);
}
}
private byte ReadPort(ushort port)
{
port &= 0xFF;
if (port < 0x40) // General IO ports
{
switch (port)
{
case 0x00: return(ReadPort0());
case 0x01: return(Port01);
case 0x02: return(Port02);
case 0x03: return(0x00);
case 0x04: return(0xFF);
case 0x05: return(0x00);
case 0x06: return(0xFF);
case 0x3E: return(Port3E);
default: return(0xFF);
}
}
if (port < 0x80) // VDP Vcounter/HCounter
{
if ((port & 1) == 0)
{
return(Vdp.ReadVLineCounter());
}
else
{
return(Vdp.ReadHLineCounter());
}
}
if (port < 0xC0) // VDP data/control ports
{
if ((port & 1) == 0)
{
return(Vdp.ReadData());
}
else
{
return(Vdp.ReadVdpStatus());
}
}
switch (port)
{
case 0xC0:
case 0xDC: return(ReadControls1());
case 0xC1:
case 0xDD: return(ReadControls2());
case 0xF2: return(HasYM2413 ? YM2413.DetectionValue : (byte)0xFF);
default: return(0xFF);
}
}