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ym2612: support TimerA and TimerB

This commit is contained in:
beirich 2012-04-29 06:05:15 +00:00
parent d9134ac6ce
commit 59eb4b4abe
6 changed files with 137 additions and 37 deletions
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1
BizHawk.Emulation/BizHawk.Emulation.csproj
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@ -328,6 +328,7 @@
<Compile Include="Consoles\Sega\SMS\SMS.cs" />
<Compile Include="Consoles\Sega\SMS\VDP.cs" />
<Compile Include="Sound\YM2413.cs" />
<Compile Include="Sound\YM2612.Timers.cs" />
<Compile Include="Util.cs" />
<Compile Include="Sound\Utilities\Waves.cs" />
</ItemGroup>

14
BizHawk.Emulation/Consoles/Sega/Genesis/Genesis.cs
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@ -105,12 +105,14 @@ namespace BizHawk.Emulation.Consoles.Sega
VDP.RenderLine();
MainCPU.ExecuteCycles(487); // 488??
if (Z80Runnable)
{
//Console.WriteLine("running z80");
SoundCPU.ExecuteCycles(228);
SoundCPU.Interrupt = false;
}
if (Z80Runnable)
{
//Console.WriteLine("running z80");
SoundCPU.ExecuteCycles(228);
SoundCPU.Interrupt = false;
} else {
SoundCPU.TotalExecutedCycles += 228; // I emulate the YM2612 synced to Z80 clock, for better or worse. Keep the timer going even if Z80 isn't running.
}
if (VDP.ScanLine == 224)
{

3
BizHawk.Emulation/Sound/SN76489.cs
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@ -422,6 +422,9 @@ namespace BizHawk.Emulation.Sound
public void GetSamples(short[] samples)
{
int elapsedCycles = frameStopTime - frameStartTime;
if (elapsedCycles == 0)
elapsedCycles = 1; // hey it's better than diving by zero
int start = 0;
while (commands.Count > 0)
{

49
BizHawk.Emulation/Sound/YM2612.IO.cs
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@ -31,12 +31,18 @@ this correctly right now.
*/
public byte ReadStatus(int clock)
{
// default status: not BUSY, both timers tripped
return 3;
UpdateTimers(clock);
byte retval = 0;
if (TimerATripped) retval |= 1;
if (TimerBTripped) retval |= 2;
return retval;
}
public void Write(int addr, byte value, int clock)
{
UpdateTimers(clock);
if (addr == 0)
{
PartSelect = 1;
@ -65,42 +71,22 @@ this correctly right now.
void WriteCommand(QueuedCommand cmd)
{
if (cmd.Part == 1)
Part1_WriteRegister(cmd.Register, cmd.Data, 0); // TODO remove clock 0 ?
Part1_WriteRegister(cmd.Register, cmd.Data);
else
Part2_WriteRegister(cmd.Register, cmd.Data);
}
void WriteTimerA_MSB_24(byte value, int clock)
{
Console.WriteLine("Timer A (msb) {0:X2}", value);
}
void WriteTimerA_LSB_25(byte value, int clock)
{
Console.WriteLine("Timer A (lsb) {0:X2}", value);
}
void WriteTimerB_26(byte value, int clock)
{
Console.WriteLine("Timer B {0:X2}", value);
}
void WriteTimerControl_27(byte value, int clock)
{
Console.WriteLine("Timer control {0:X2}", value);
}
// information on TIMER is on pg 6
void Part1_WriteRegister(byte register, byte value, int clock) // TODO remove clock?
void Part1_WriteRegister(byte register, byte value)
{
switch (register)
{
case 0x22: Console.WriteLine("LFO Control {0:X2}", value); break;
//case 0x22: Console.WriteLine("LFO Control {0:X2}", value); break;
case 0x24: break; // Timer A MSB, handled immediately
case 0x25: break; // Timer A LSB, handled immediately
case 0x26: break; // Timer B, handled immediately
case 0x27: Console.WriteLine("$27: Ch3 Mode / Timer Control {0:X2}", value); break; // determines if CH3 has 1 frequency or 4 frequencies.
case 0x28: Console.WriteLine("Operator Key On/Off Ctrl {0:X2}", value); break;
//case 0x27: Console.WriteLine("$27: Ch3 Mode / Timer Control {0:X2}", value); break; // determines if CH3 has 1 frequency or 4 frequencies.
//case 0x28: Console.WriteLine("Operator Key On/Off Ctrl {0:X2}", value); break;
case 0x2A: DacValue = value; break;
case 0x2B: DacEnable = (value & 0x80) != 0; break;
case 0x2C: throw new Exception("something wrote to ym2612 port $2C!"); //http://forums.sonicretro.org/index.php?showtopic=28589
@ -117,10 +103,11 @@ this correctly right now.
// PG4 has some info on frquency calculations
default:
if (register >= 0x30 && register < 0xA0)
/* if (register >= 0x30 && register < 0xA0)
Console.WriteLine("P1 FM Channel data write");
else
Console.WriteLine("P1 REG {0:X2} WRITE {1:X2}", register, value); break;
Console.WriteLine("P1 REG {0:X2} WRITE {1:X2}", register, value); */
break;
}
}
@ -128,10 +115,10 @@ this correctly right now.
{
// NOTE. Only first bank has multi-frequency CSM/Special mode. This mode can't work on CH6.
if (register >= 0x30 && register < 0xA0)
/*if (register >= 0x30 && register < 0xA0)
Console.WriteLine("P2 FM Channel data write");
else
Console.WriteLine("P2 REG {0:X2} WRITE {1:X2}", register, value);
Console.WriteLine("P2 REG {0:X2} WRITE {1:X2}", register, value);*/
}
public class QueuedCommand

104
BizHawk.Emulation/Sound/YM2612.Timers.cs Normal file
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@ -0,0 +1,104 @@
using System;
namespace BizHawk.Emulation.Sound
{
// The master clock on the genesis is 53,693,175 MCLK / sec (NTSC)
// 53,203,424 MCLK / sec (PAL)
// 7,670,454 68K cycles / sec (7 MCLK divisor)
// 3,579,545 Z80 cycles / sec (15 MCLK divisor)
// YM2612 is fed by EXT CLOCK: 7,670,454 ECLK / sec (NTSC)
// (Same clock on 68000) 7,600,489 ECLK / sec (PAL)
// YM2612 has /6 divisor on the EXT CLOCK.
// YM2612 takes 24 cycles to generate a sample. 6*24 = 144. This is where the /144 divisor comes from.
// YM2612 native output rate is 7670454 / 144 = 53267 hz (NTSC), 52781 hz (PAL)
// Timer A ticks at the native output rate (53267 times per second for NTSC).
// Timer B ticks down with a /16 divisor. (3329 times per second for NTSC).
// Ergo, Timer A ticks every 67.2 Z80 cycles. Timer B ticks every 1075.2 Z80 cycles.
public partial class YM2612
{
const float timerAZ80Factor = 67.2f;
const float timerBZ80Factor = 1075.2f;
int TimerAPeriod, TimerBPeriod;
bool TimerATripped, TimerBTripped;
int TimerAResetClock, TimerBResetClock;
int TimerALastReset, TimerBLastReset;
byte TimerControl27;
bool TimerALoad { get { return (TimerControl27 & 1) != 0; } }
bool TimerBLoad { get { return (TimerControl27 & 2) != 0; } }
bool TimerAEnable { get { return (TimerControl27 & 4) != 0; } }
bool TimerBEnable { get { return (TimerControl27 & 8) != 0; } }
bool TimerAReset { get { return (TimerControl27 & 16) != 0; } }
bool TimerBReset { get { return (TimerControl27 & 32) != 0; } }
void InitTimers()
{
TimerAResetClock = 68812;
TimerBResetClock = 275200;
}
void UpdateTimers(int clock)
{
int elapsedCyclesSinceLastTimerAReset = clock - TimerALastReset;
if (elapsedCyclesSinceLastTimerAReset > TimerAResetClock)
{
if (TimerAEnable)
TimerATripped = true;
int numTimesTripped = elapsedCyclesSinceLastTimerAReset / TimerAResetClock;
TimerALastReset += (TimerAResetClock * numTimesTripped);
}
int elapsedCyclesSinceLastTimerBReset = clock - TimerBLastReset;
if (elapsedCyclesSinceLastTimerBReset > TimerBResetClock)
{
if (TimerBEnable)
TimerBTripped = true;
int numTimesTripped = elapsedCyclesSinceLastTimerBReset / TimerBResetClock;
TimerBLastReset += (TimerBResetClock * numTimesTripped);
}
}
void WriteTimerA_MSB_24(byte value, int clock)
{
TimerAPeriod = (value << 2) | (TimerAPeriod & 3);
TimerAResetClock = (int)((1024 - TimerAPeriod) * timerAZ80Factor);
}
void WriteTimerA_LSB_25(byte value, int clock)
{
TimerAPeriod = (TimerAPeriod & 0x3FC) | (value & 3);
TimerAResetClock = (int)((1024 - TimerAPeriod) * timerAZ80Factor);
}
void WriteTimerB_26(byte value, int clock)
{
TimerBPeriod = value;
TimerBResetClock = (int)((256 - TimerBPeriod) * timerBZ80Factor);
}
void WriteTimerControl_27(byte value, int clock)
{
bool lagALoad = TimerALoad;
bool lagBLoad = TimerBLoad;
TimerControl27 = value;
if (!lagALoad && TimerALoad)
TimerALastReset = clock;
if (!lagBLoad && TimerBLoad)
TimerBLastReset = clock;
if (TimerAReset) TimerATripped = false;
if (TimerBReset) TimerBTripped = false;
}
}
}

3
BizHawk.Emulation/Sound/YM2612.cs
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@ -19,10 +19,13 @@ namespace BizHawk.Emulation.Sound
Channels[3] = new Channel();
Channels[4] = new Channel();
Channels[5] = new Channel();
InitTimers();
}
public void Reset()
{
throw new Exception("something is resetting the ym2612");
}
public void BeginFrame(int clock)