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Atari - progress on DPC mapper, still doesn't work

This commit is contained in:
adelikat 2012-11-01 01:54:33 +00:00
parent 3db5afe8a7
commit ae7bb1b590
1 changed files with 158 additions and 28 deletions
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186
BizHawk.Emulation/Consoles/Atari/2600/Mappers/mDPC.cs
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@ -12,7 +12,7 @@ namespace BizHawk
{
int bank_4k = 0;
IntBuffer Counters = new IntBuffer(8);
IntBuffer Flags = new IntBuffer(8);
ByteBuffer Flags = new ByteBuffer(8);
IntBuffer Tops = new IntBuffer(8);
IntBuffer Bottoms = new IntBuffer(8);
ByteBuffer DisplayBank_2k = new ByteBuffer(2048);
@ -43,42 +43,39 @@ namespace BizHawk
switch (function)
{
default:
result = 0;
break;
case 0x00:
if (index < 4)
{
result = RandomNumber;
}
else
else //it's a music read
{
result = 0;//TODO
//byte[8] musicAmplitudes = {
// 0x00, 0x04, 0x05, 0x09, 0x06, 0x0a, 0x0b, 0x0f
//};
byte[] MusicAmplitudes = {
0x00, 0x04, 0x05, 0x09, 0x06, 0x0a, 0x0b, 0x0f
};
//// Update the music data fetchers (counter & flag)
//UpdateMusicModeDataFetchers();
UpdateMusicModeDataFetchers();
//byte i = 0;
//if(MusicMode[0] && Flags[5])
//{
// i |= 0x01;
//}
//if(MusicMode[1] && Flags[6])
//{
// i |= 0x02;
//}
//if(MusicMode[2] && Flags[7])
//{
// i |= 0x04;
//}
byte i = 0;
if(MusicMode[0] && Flags[5] > 0)
{
i |= 0x01;
}
if(MusicMode[1] && Flags[6] > 0)
{
i |= 0x02;
}
if(MusicMode[2] && Flags[7] > 0)
{
i |= 0x04;
}
//result = MusicAmplitudes[i];
result = MusicAmplitudes[i];
}
break;
case 0x00:
result = 0; //TODO
break;
case 0x01:
result = DisplayBank_2k[2047 - Counters[index]];
break;
@ -86,9 +83,16 @@ namespace BizHawk
result = DisplayBank_2k[2047 - (Counters[index] & Flags[index])];
break;
case 0x07:
result = Flags[index];
break;
}
// Clock the selected data fetcher's counter if needed
if ((index < 5) || ((index >= 5) && (!MusicMode[index - 5])))
{
Counters[index] = (Counters[index] - 1) & 0x07ff;
}
return result;
}
else
@ -105,11 +109,70 @@ namespace BizHawk
public override void WriteMemory(ushort addr, byte value)
{
Address(addr);
if (addr < 0x1000)
{
base.WriteMemory(addr, value);
}
addr &= 0x0FFF;
// Clock the random number generator. This should be done for every
// cartridge access, however, we're only doing it for the DPC and
// hot-spot accesses to save time.
ClockRandomNumberGenerator();
if ((addr >= 0x0040) && (addr < 0x0080))
{
// Get the index of the data fetcher that's being accessed
int index = addr & 0x07;
int function = (addr >> 3) & 0x07;
switch (function)
{
case 0x00: // DFx top count
Tops[index] = value;
Flags[index] = 0x00;
break;
case 0x01: // DFx bottom count
Bottoms[index] = value;
break;
case 0x02: // DFx counter low
if ((index >= 5) && MusicMode[index - 5])
{
Counters[index] = (Counters[index] & 0x0700) | Tops[index]; // Data fetcher is in music mode so its low counter value should be loaded from the top register not the poked value
}
else
{
// Data fetcher is either not a music mode data fetcher or it
// isn't in music mode so it's low counter value should be loaded
// with the poked value
Counters[index] = (Counters[index] & 0x0700) | value;
}
break;
case 0x03: // DFx counter high
Counters[index] = ((value & 0x07) << 8) | (Counters[index] & 0x00ff);
// Execute special code for music mode data fetchers
if (index >= 5)
{
MusicMode[index - 5] = (value & 0x10) > 0 ? true : false;
// NOTE: We are not handling the clock source input for
// the music mode data fetchers. We're going to assume
// they always use the OSC input.
}
break;
case 0x06: // Random Number Generator Reset
RandomNumber = 1;
break;
default:
break;
}
}
else
{
Address(addr);
}
return;
}
private void Address(ushort addr)
@ -134,6 +197,7 @@ namespace BizHawk
public override void SyncState(Serializer ser)
{
//TODO
base.SyncState(ser);
ser.Sync("bank_4k", ref bank_4k);
ser.Sync("DisplayBank_2k", ref DisplayBank_2k);
@ -142,9 +206,75 @@ namespace BizHawk
ser.Sync("RandomNumber", ref RandomNumber);
}
private double FractionalClocks;
private void UpdateMusicModeDataFetchers()
{
//TODO
// Calculate the number of cycles since the last update
//int cycles = mySystem->cycles() - mySystemCycles;
//mySystemCycles = mySystem->cycles();
int cycles = 0; //TODO: need to get cycles!
// Calculate the number of DPC OSC clocks since the last update
double clocks = ((20000.0 * cycles) / 1193191.66666667) + FractionalClocks;
int wholeClocks = (int)clocks;
FractionalClocks = clocks - (double)wholeClocks;
if (wholeClocks <= 0)
{
return;
}
// Let's update counters and flags of the music mode data fetchers
for (int x = 5; x <= 7; ++x)
{
// Update only if the data fetcher is in music mode
if (MusicMode[x - 5])
{
int top = Tops[x] + 1;
int newLow = Counters[x] & 0x00ff;
if (Tops[x] != 0)
{
newLow -= (wholeClocks % top);
if (newLow < 0)
{
newLow += top;
}
}
else
{
newLow = 0;
}
// Update flag register for this data fetcher
if (newLow <= Bottoms[x])
{
Flags[x] = 0x00;
}
else if (newLow <= Tops[x])
{
Flags[x] = 0xff;
}
Counters[x] = (Counters[x] & 0x0700) | newLow;
}
}
}
private void ClockRandomNumberGenerator()
{
// Table for computing the input bit of the random number generator's
// shift register (it's the NOT of the EOR of four bits)
byte[] f = {
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
};
// Using bits 7, 5, 4, & 3 of the shift register compute the input
// bit for the shift register
byte bit = f[((RandomNumber >> 3) & 0x07) |
((RandomNumber & 0x80) > 0 ? 0x08 : 0x00)];
// Update the shift register
RandomNumber = (byte)(RandomNumber << 1 | bit);
}
}
}