public byte ReadMemory(ushort addr, bool peek)
{
var maskedAddr = (ushort)(addr & 0x000F);
byte coll = 0;
int mask = 0;
if (maskedAddr == 0x00) // CXM0P
{
coll = (byte)((((_player0.Missile.Collisions & CXP1) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXP0) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x01) // CXM1P
{
coll = (byte)((((_player1.Missile.Collisions & CXP0) != 0) ? 0x80 : 0x00) | (((_player1.Missile.Collisions & CXP1) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x02) // CXP0FB
{
coll = (byte)((((_player0.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player0.Collisions & CXBL) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x03) // CXP1FB
{
coll = (byte)((((_player1.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player1.Collisions & CXBL) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x04) // CXM0FB
{
coll = (byte)((((_player0.Missile.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXBL) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x05) // CXM1FB
{
coll = (byte)((((_player1.Missile.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player1.Missile.Collisions & CXBL) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
if (maskedAddr == 0x06) // CXBLPF
{
coll = (byte)(((_ball.Collisions & CXPF) != 0) ? 0x80 : 0x00);
mask = 0x7f;
}
if (maskedAddr == 0x07) // CXPPMM
{
coll = (byte)((((_player0.Collisions & CXP1) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXM1) != 0) ? 0x40 : 0x00));
mask = 0x3f;
}
// inputs 0-3 are measured by a charging capacitor, these inputs are used with the paddles and the keyboard
// Changing the hard coded value will change the paddle position. The range seems to be roughly 0-56000 according to values from stella
// 6105 roughly centers the paddle in Breakout
if (maskedAddr == 0x08) // INPT0
{
if (_core.ReadPot1(0) > 0 && _capCharging && _core.Cpu.TotalExecutedCycles - _capChargeStart >= _core.ReadPot1(0))
{
coll = 0x80;
}
else
{
coll = 0x00;
}
mask = 0x7f;
}
if (maskedAddr == 0x09) // INPT1
{
if (_core.ReadPot1(1) > 0 && _capCharging && _core.Cpu.TotalExecutedCycles - _capChargeStart >= _core.ReadPot1(1))
{
coll = 0x80;
}
else
{
coll = 0x00;
}
mask = 0x7f;
}
if (maskedAddr == 0x0A) // INPT2
{
if (_core.ReadPot2(0) > 0 && _capCharging && _core.Cpu.TotalExecutedCycles - _capChargeStart >= _core.ReadPot2(0))
{
coll = 0x80;
}
else
{
coll = 0x00;
}
mask = 0x7f;
}
if (maskedAddr == 0x0B) // INPT3
{
if (_core.ReadPot2(1) > 0 && _capCharging && _core.Cpu.TotalExecutedCycles - _capChargeStart >= _core.ReadPot2(1))
{
coll = 0x80;
}
else
{
coll = 0x00;
}
mask = 0x7f;
}
if (maskedAddr == 0x0C) // INPT4
{
coll = (byte)((_core.ReadControls1(peek) & 0x08) != 0 ? 0x80 : 0x00);
mask = 0x7f;
}
if (maskedAddr == 0x0D) // INPT5
{
coll = (byte)((_core.ReadControls2(peek) & 0x08) != 0 ? 0x80 : 0x00);
mask = 0x7f;
}
// some bits of the databus will be undriven when a read call is made. Our goal here is to sort out what
// happens to the undriven pins. Most of the time, they will be in whatever state they were when previously
// assigned in some other bus access, so let's go with that.
coll += (byte)(mask & BusState);
if (!peek)
{
BusState = coll;
}
return(coll);
}
public byte ReadMemory(ushort addr, bool peek)
{
var maskedAddr = (ushort)(addr & 0x000F);
if (maskedAddr == 0x00) // CXM0P
{
return((byte)((((_player0.Missile.Collisions & CXP1) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXP0) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x01) // CXM1P
{
return((byte)((((_player1.Missile.Collisions & CXP0) != 0) ? 0x80 : 0x00) | (((_player1.Missile.Collisions & CXP1) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x02) // CXP0FB
{
return((byte)((((_player0.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player0.Collisions & CXBL) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x03) // CXP1FB
{
return((byte)((((_player1.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player1.Collisions & CXBL) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x04) // CXM0FB
{
return((byte)((((_player0.Missile.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXBL) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x05) // CXM1FB
{
return((byte)((((_player1.Missile.Collisions & CXPF) != 0) ? 0x80 : 0x00) | (((_player1.Missile.Collisions & CXBL) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x06) // CXBLPF
{
return((byte)(((_ball.Collisions & CXPF) != 0) ? 0x80 : 0x00));
}
if (maskedAddr == 0x07) // CXPPMM
{
return((byte)((((_player0.Collisions & CXP1) != 0) ? 0x80 : 0x00) | (((_player0.Missile.Collisions & CXM1) != 0) ? 0x40 : 0x00)));
}
if (maskedAddr == 0x08) // INPT0
{
// Changing the hard coded value will change the paddle position. The range seems to be roughly 0-56000 according to values from stella
// 6105 roughly centers the paddle in Breakout
if (_capCharging && _core.Cpu.TotalExecutedCycles - _capChargeStart >= 6105)
{
return(0x80);
}
return(0x00);
}
if (maskedAddr == 0x0C) // INPT4
{
return((byte)((_core.ReadControls1(peek) & 0x08) != 0 ? 0x80 : 0x00));
}
if (maskedAddr == 0x0D) // INPT5
{
return((byte)((_core.ReadControls2(peek) & 0x08) != 0 ? 0x80 : 0x00));
}
return(0x00);
}
