diff --git a/Core/apu.c b/Core/apu.c index 0826eb5d..dc64ca5e 100755 --- a/Core/apu.c +++ b/Core/apu.c @@ -120,8 +120,7 @@ void GB_apu_div_event(GB_gameboy_t *gb) if (!gb->apu.global_enable) return; gb->apu.div_divider++; - /* gb->apu.div_divider is even; handle volume envelopes */ - if ((gb->apu.div_divider & 1) == 0) { + if ((gb->apu.div_divider & 7) == 0) { for (unsigned i = GB_SQUARE_2 + 1; i--;) { uint8_t nrx2 = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22]; @@ -135,7 +134,7 @@ void GB_apu_div_event(GB_gameboy_t *gb) gb->apu.square_channels[i].current_volume--; } - gb->apu.square_channels[i].volume_countdown = (nrx2 & 7) * 4; + gb->apu.square_channels[i].volume_countdown = nrx2 & 7; uint8_t duty = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR11 :GB_IO_NR21] >> 6; update_sample(gb, i, @@ -158,7 +157,7 @@ void GB_apu_div_event(GB_gameboy_t *gb) gb->apu.noise_channel.current_volume--; } - gb->apu.noise_channel.volume_countdown = (nr42 & 7) * 4; + gb->apu.noise_channel.volume_countdown = nr42 & 7; update_sample(gb, GB_NOISE, (gb->apu.noise_channel.lfsr & 1) ? @@ -167,8 +166,8 @@ void GB_apu_div_event(GB_gameboy_t *gb) } } } - /* gb->apu.div_divider is odd; handle length controls */ - else { + + if ((gb->apu.div_divider & 1) == 1) { for (unsigned i = GB_SQUARE_2 + 1; i--;) { if (gb->apu.square_channels[i].length_enabled) { if (gb->apu.square_channels[i].pulse_length) { @@ -537,7 +536,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) } } gb->apu.square_channels[index].current_volume = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] >> 4; - gb->apu.square_channels[index].volume_countdown = (gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] & 7) * 4; + gb->apu.square_channels[index].volume_countdown = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] & 7; if ((gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] & 0xF8) != 0) { gb->apu.is_active[index] = true; @@ -711,7 +710,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) } gb->apu.noise_channel.current_volume = gb->io_registers[GB_IO_NR42] >> 4; - gb->apu.noise_channel.volume_countdown = (gb->io_registers[GB_IO_NR42] & 7) * 4; + gb->apu.noise_channel.volume_countdown = gb->io_registers[GB_IO_NR42] & 7; if ((gb->io_registers[GB_IO_NR42] & 0xF8) != 0) { gb->apu.is_active[GB_NOISE] = true;