bsnes/higan/gb/apu/sequencer.cpp

143 lines
3.6 KiB
C++

auto APU::Sequencer::run() -> void {
if(enable == false) {
center = 0;
left = 0;
right = 0;
return;
}
int sample = 0;
sample += apu.square1.output;
sample += apu.square2.output;
sample += apu.wave.output;
sample += apu.noise.output;
center = (sample * 512) - 16384;
sample = 0;
if(square1.leftEnable) sample += apu.square1.output;
if(square2.leftEnable) sample += apu.square2.output;
if( wave.leftEnable) sample += apu.wave.output;
if( noise.leftEnable) sample += apu.noise.output;
sample = (sample * 512) - 16384;
sample = (sample * (leftVolume + 1)) / 8;
left = sample;
sample = 0;
if(square1.rightEnable) sample += apu.square1.output;
if(square2.rightEnable) sample += apu.square2.output;
if( wave.rightEnable) sample += apu.wave.output;
if( noise.rightEnable) sample += apu.noise.output;
sample = (sample * 512) - 16384;
sample = (sample * (rightVolume + 1)) / 8;
right = sample;
//reduce audio volume
center >>= 1;
left >>= 1;
right >>= 1;
}
auto APU::Sequencer::read(uint16 addr) -> uint8 {
if(addr == 0xff24) { //NR50
return leftEnable << 7 | leftVolume << 4 | rightEnable << 3 | rightVolume;
}
if(addr == 0xff25) { //NR51
return noise.leftEnable << 7
| wave.leftEnable << 6
| square2.leftEnable << 5
| square1.leftEnable << 4
| noise.rightEnable << 3
| wave.rightEnable << 2
| square2.rightEnable << 1
| square1.rightEnable << 0;
}
if(addr == 0xff26) { //NR52
return enable << 7 | 0x70
| apu.noise.enable << 3
| apu.wave.enable << 2
| apu.square2.enable << 1
| apu.square1.enable << 0;
}
return 0xff;
}
auto APU::Sequencer::write(uint16 addr, uint8 data) -> void {
if(addr == 0xff24) { //NR50
leftEnable = data.bit (7);
leftVolume = data.bits(6,4);
rightEnable = data.bit (3);
rightVolume = data.bits(2,0);
}
if(addr == 0xff25) { //NR51
noise.leftEnable = data.bit(7);
wave.leftEnable = data.bit(6);
square2.leftEnable = data.bit(5);
square1.leftEnable = data.bit(4);
noise.rightEnable = data.bit(3);
wave.rightEnable = data.bit(2);
square2.rightEnable = data.bit(1);
square1.rightEnable = data.bit(0);
}
if(addr == 0xff26) { //NR52
if(enable != data.bit(7)) {
enable = data.bit(7);
if(!enable) {
//power(bool) resets length counters when true (eg for CGB only)
apu.square1.power(Model::GameBoyColor());
apu.square2.power(Model::GameBoyColor());
apu.wave.power(Model::GameBoyColor());
apu.noise.power(Model::GameBoyColor());
power();
} else {
apu.phase = 0;
}
}
}
}
auto APU::Sequencer::power() -> void {
leftEnable = 0;
leftVolume = 0;
rightEnable = 0;
rightVolume = 0;
noise.leftEnable = 0;
wave.leftEnable = 0;
square2.leftEnable = 0;
square1.leftEnable = 0;
noise.rightEnable = 0;
wave.rightEnable = 0;
square2.rightEnable = 0;
square1.rightEnable = 0;
enable = 0;
center = 0;
left = 0;
right = 0;
}
auto APU::Sequencer::serialize(serializer& s) -> void {
s.integer(leftEnable);
s.integer(leftVolume);
s.integer(rightEnable);
s.integer(rightVolume);
s.integer(noise.leftEnable);
s.integer(wave.leftEnable);
s.integer(square2.leftEnable);
s.integer(square1.leftEnable);
s.integer(noise.rightEnable);
s.integer(wave.rightEnable);
s.integer(square2.rightEnable);
s.integer(square1.rightEnable);
s.integer(enable);
s.integer(center);
s.integer(left);
s.integer(right);
}