mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-02-24 15:12:23 +01:00
94b2538af5
byuu says: Basically just a project rename, with s/bsnes/higan and the new icon from lowkee added in. It won't compile on Windows because I forgot to update the resource.rc file, and a path transform command isn't working on Windows. It was really just meant as a starting point, so that v091 WIPs can flow starting from .00 with the new name (it overshadows bsnes v091, so publicly speaking this "shouldn't exist" and will probably be deleted from Google Code when v092 is ready.)
113 lines
2.3 KiB
C++
Executable File
113 lines
2.3 KiB
C++
Executable File
#ifdef APU_CPP
|
|
|
|
bool APU::Noise::dac_enable() {
|
|
return (envelope_volume || envelope_direction);
|
|
}
|
|
|
|
void APU::Noise::run() {
|
|
if(period && --period == 0) {
|
|
period = divisor << frequency;
|
|
if(frequency < 14) {
|
|
bool bit = (lfsr ^ (lfsr >> 1)) & 1;
|
|
lfsr = (lfsr >> 1) ^ (bit << (narrow_lfsr ? 6 : 14));
|
|
}
|
|
}
|
|
|
|
uint4 sample = (lfsr & 1) ? (uint4)0 : volume;
|
|
if(enable == false) sample = 0;
|
|
|
|
output = sample;
|
|
}
|
|
|
|
void APU::Noise::clock_length() {
|
|
//if(counter && length) {
|
|
// if(--length == 0) enable = false;
|
|
//}
|
|
if(enable && counter) {
|
|
if(++length == 0) enable = false;
|
|
}
|
|
}
|
|
|
|
void APU::Noise::clock_envelope() {
|
|
if(enable && envelope_frequency && --envelope_period == 0) {
|
|
envelope_period = envelope_frequency;
|
|
if(envelope_direction == 0 && volume > 0) volume--;
|
|
if(envelope_direction == 1 && volume < 15) volume++;
|
|
}
|
|
}
|
|
|
|
void APU::Noise::write(unsigned r, uint8 data) {
|
|
if(r == 1) { //$ff20 NR41
|
|
//length = 64 - (data & 0x3f);
|
|
length = data & 0x3f;
|
|
}
|
|
|
|
if(r == 2) { //$ff21 NR42
|
|
envelope_volume = data >> 4;
|
|
envelope_direction = data & 0x08;
|
|
envelope_frequency = data & 0x07;
|
|
if(dac_enable() == false) enable = false;
|
|
}
|
|
|
|
if(r == 3) { //$ff22 NR43
|
|
frequency = data >> 4;
|
|
narrow_lfsr = data & 0x08;
|
|
divisor = (data & 0x07) << 4;
|
|
if(divisor == 0) divisor = 8;
|
|
period = divisor << frequency;
|
|
}
|
|
|
|
if(r == 4) { //$ff34 NR44
|
|
bool initialize = data & 0x80;
|
|
counter = data & 0x40;
|
|
|
|
if(initialize) {
|
|
enable = dac_enable();
|
|
lfsr = ~0U;
|
|
envelope_period = envelope_frequency;
|
|
volume = envelope_volume;
|
|
//if(length == 0) length = 64;
|
|
}
|
|
}
|
|
}
|
|
|
|
void APU::Noise::power() {
|
|
enable = 0;
|
|
|
|
envelope_volume = 0;
|
|
envelope_direction = 0;
|
|
envelope_frequency = 0;
|
|
frequency = 0;
|
|
narrow_lfsr = 0;
|
|
divisor = 0;
|
|
counter = 0;
|
|
|
|
output = 0;
|
|
length = 0;
|
|
envelope_period = 0;
|
|
volume = 0;
|
|
period = 0;
|
|
lfsr = 0;
|
|
}
|
|
|
|
void APU::Noise::serialize(serializer &s) {
|
|
s.integer(enable);
|
|
|
|
s.integer(envelope_volume);
|
|
s.integer(envelope_direction);
|
|
s.integer(envelope_frequency);
|
|
s.integer(frequency);
|
|
s.integer(narrow_lfsr);
|
|
s.integer(divisor);
|
|
s.integer(counter);
|
|
|
|
s.integer(output);
|
|
s.integer(length);
|
|
s.integer(envelope_period);
|
|
s.integer(volume);
|
|
s.integer(period);
|
|
s.integer(lfsr);
|
|
}
|
|
|
|
#endif
|