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GB: APU - Implemented volume update behavior on register writes

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Fixes sound in Prehistorik intro
This commit is contained in:
Sour 2020-05-24 22:41:54 -04:00
parent 4274c481d7
commit 9f7ee662f9
3 changed files with 28 additions and 7 deletions
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27
Core/GbSquareChannel.h
View file

@ -90,7 +90,7 @@ public:
void ClockEnvelope()
{
if(_state.EnvTimer > 0) {
if(_state.EnvTimer > 0 && !_state.EnvStopped) {
_state.EnvTimer--;
if(_state.EnvTimer == 0) {
@ -98,6 +98,8 @@ public:
_state.Volume++;
} else if(!_state.EnvRaiseVolume && _state.Volume > 0) {
_state.Volume--;
} else {
_state.EnvStopped = true;
}
_state.EnvTimer = _state.EnvPeriod;
@ -170,15 +172,33 @@ public:
_state.Duty = (value & 0xC0) >> 6;
break;
case 2:
case 2: {
if(_state.EnvPeriod == 0 && !_state.EnvStopped){
//"If the old envelope period was zero and the envelope is still doing automatic updates, volume is incremented by 1"
_state.Volume++;
} else if(!_state.EnvRaiseVolume) {
//"otherwise if the envelope was in subtract mode, volume is incremented by 2"
_state.Volume += 2;
}
bool raiseVolume = (value & 0x08) != 0;
if(raiseVolume != _state.EnvRaiseVolume) {
//"If the mode was changed (add to subtract or subtract to add), volume is set to 16 - volume."
_state.Volume = 16 - _state.Volume;
}
//"Only the low 4 bits of volume are kept after the above operations."
_state.Volume &= 0xF;
_state.EnvPeriod = value & 0x07;
_state.EnvRaiseVolume = (value & 0x08) != 0;
_state.EnvRaiseVolume = raiseVolume;
_state.EnvVolume = (value & 0xF0) >> 4;
if(!(value & 0xF8)) {
_state.Enabled = false;
}
break;
}
case 3:
_state.Frequency = (_state.Frequency & 0x700) | value;
@ -204,6 +224,7 @@ public:
//Volume envelope timer is reloaded with period.
_state.EnvTimer = _state.EnvPeriod;
_state.EnvStopped = false;
//Channel volume is reloaded from NRx2.
_state.Volume = _state.EnvVolume;

1
Core/GbTypes.h
View file

@ -219,6 +219,7 @@ struct GbSquareState
bool EnvRaiseVolume;
uint8_t EnvPeriod;
uint8_t EnvTimer;
bool EnvStopped;
uint8_t Duty;
uint16_t Frequency;

7
UI/Interop/DebugState.cs
View file

@ -693,6 +693,7 @@ namespace Mesen.GUI
public byte H;
public byte L;
[MarshalAs(UnmanagedType.I1)] public bool EiPending;
[MarshalAs(UnmanagedType.I1)] public bool IME;
[MarshalAs(UnmanagedType.I1)] public bool Halted;
}
@ -713,6 +714,7 @@ namespace Mesen.GUI
[MarshalAs(UnmanagedType.I1)] public bool StatIrqFlag;
public byte LyCompare;
[MarshalAs(UnmanagedType.I1)] public bool LyCoincidenceFlag;
public byte BgPalette;
public byte ObjPalette0;
public byte ObjPalette1;
@ -735,10 +737,6 @@ namespace Mesen.GUI
public UInt32 FrameCount;
public byte CgbVramBank;
public UInt16 CgbDmaSource;
public UInt16 CgbDmaDest;
public byte CgbDmaLength;
[MarshalAs(UnmanagedType.I1)] public bool CgbHdmaMode;
public byte CgbBgPalPosition;
[MarshalAs(UnmanagedType.I1)] public bool CgbBgPalAutoInc;
@ -768,6 +766,7 @@ namespace Mesen.GUI
[MarshalAs(UnmanagedType.I1)] public bool EnvRaiseVolume;
public byte EnvPeriod;
public byte EnvTimer;
[MarshalAs(UnmanagedType.I1)] public bool EnvStopped;
public byte Duty;
public UInt16 Frequency;