From 2aa171e0ea62ab243f89ddecadf67839a41a99fe Mon Sep 17 00:00:00 2001 From: Lior Halphon Date: Sat, 9 Jan 2021 16:26:56 +0200 Subject: [PATCH] Better sample alignment on pre-CGB-D models --- Core/apu.c | 47 +++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 43 insertions(+), 4 deletions(-) diff --git a/Core/apu.c b/Core/apu.c index 2596e0f2..d9a04409 100644 --- a/Core/apu.c +++ b/Core/apu.c @@ -394,6 +394,9 @@ static void trigger_sweep_calculation(GB_gameboy_t *gb) /* Recalculation and overflow check only occurs after a delay */ gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 5 - gb->apu.lf_div; + if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) { + gb->apu.square_sweep_calculate_countdown += 2; + } gb->apu.enable_zombie_calculate_stepping = false; gb->apu.unshifted_sweep = !(gb->io_registers[GB_IO_NR10] & 0x7); gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7; @@ -618,10 +621,10 @@ void GB_apu_run(GB_gameboy_t *gb) /* Step LFSR */ if (new_bit && !old_bit) { - step_lfsr(gb, cycles - cycles_left); if (cycles_left == 0 && gb->apu.samples[GB_NOISE] == 0) { gb->apu.pcm_mask[1] &= 0x0F; } + step_lfsr(gb, cycles - cycles_left); } } if (cycles_left) { @@ -823,6 +826,7 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) case GB_IO_NR14: case GB_IO_NR24: { + /* TODO: GB_MODEL_CGB_D fails channel_1_sweep_restart_2, don't forget when adding support for this revision! */ unsigned index = reg == GB_IO_NR24? GB_SQUARE_2: GB_SQUARE_1; bool was_active = gb->apu.is_active[index]; /* TODO: When the sample length changes right before being updated, the countdown should change to the @@ -847,6 +851,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) turning the APU off. */ if (!gb->apu.is_active[index]) { gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 6 - gb->apu.lf_div; + if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) { + gb->apu.square_channels[index].sample_countdown += 2; + } } else { unsigned extra_delay = 0; @@ -864,6 +871,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) } /* Timing quirk: if already active, sound starts 2 (2MHz) ticks earlier.*/ gb->apu.square_channels[index].sample_countdown = (gb->apu.square_channels[index].sample_length ^ 0x7FF) * 2 + 4 - gb->apu.lf_div + extra_delay; + if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) { + gb->apu.square_channels[index].sample_countdown += 2; + } } gb->apu.square_channels[index].current_volume = gb->io_registers[index == GB_SQUARE_1 ? GB_IO_NR12 : GB_IO_NR22] >> 4; @@ -893,6 +903,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) if (gb->io_registers[GB_IO_NR10] & 7) { /* APU bug: if shift is nonzero, overflow check also occurs on trigger */ gb->apu.square_sweep_calculate_countdown = (gb->io_registers[GB_IO_NR10] & 0x7) * 2 + 5 - gb->apu.lf_div; + if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) { + gb->apu.square_sweep_calculate_countdown += 2; + } gb->apu.enable_zombie_calculate_stepping = false; gb->apu.unshifted_sweep = false; if (!was_active) { @@ -905,6 +918,9 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) gb->apu.sweep_length_addend = 0; } gb->apu.channel_1_restart_hold = 2 - gb->apu.lf_div + GB_is_cgb(gb) * 2; + if (gb->model <= GB_MODEL_CGB_C && gb->apu.lf_div) { + gb->apu.channel_1_restart_hold += 2; + } gb->apu.square_sweep_countdown = ((gb->io_registers[GB_IO_NR10] >> 4) & 7) ^ 7; } } @@ -1080,10 +1096,23 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) gb->apu.channel_4_delta = 0; gb->apu.noise_channel.counter_countdown = divisor + 4; if (divisor == 2) { - gb->apu.noise_channel.counter_countdown += 1 - gb->apu.lf_div; + if (gb->model <= GB_MODEL_CGB_C) { + gb->apu.noise_channel.counter_countdown += gb->apu.lf_div; + if (!gb->cgb_double_speed) { + gb->apu.noise_channel.counter_countdown -= 1; + } + } + else { + gb->apu.noise_channel.counter_countdown += 1 - gb->apu.lf_div; + } } else { - gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 0, 3}[gb->apu.noise_channel.alignment & 3]; + if (gb->model <= GB_MODEL_CGB_C) { + gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 4, 3}[gb->apu.noise_channel.alignment & 3]; + } + else { + gb->apu.noise_channel.counter_countdown += (uint8_t[]){2, 1, 0, 3}[gb->apu.noise_channel.alignment & 3]; + } if (((gb->apu.noise_channel.alignment + 1) & 3) < 2) { if ((gb->io_registers[GB_IO_NR43] & 0x07) == 1) { gb->apu.noise_channel.counter_countdown -= 2; @@ -1094,7 +1123,17 @@ void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value) } } } - + + /* TODO: These two are quite weird. Verify further */ + if (gb->model <= GB_MODEL_CGB_C && gb->cgb_double_speed) { + if (!(gb->io_registers[GB_IO_NR43] & 0xF0) && (gb->io_registers[GB_IO_NR43] & 0x07)) { + gb->apu.noise_channel.counter_countdown -= 1; + } + else if ((gb->io_registers[GB_IO_NR43] & 0xF0) && !(gb->io_registers[GB_IO_NR43] & 0x07)) { + gb->apu.noise_channel.counter_countdown += 1; + } + } + gb->apu.noise_channel.current_volume = gb->io_registers[GB_IO_NR42] >> 4; /* The volume changes caused by NRX4 sound start take effect instantly (i.e. the effect the previously