1455 lines
59 KiB
C
1455 lines
59 KiB
C
#include <stdint.h>
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#include <math.h>
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#include <string.h>
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#include <assert.h>
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#include "gb.h"
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#define likely(x) __builtin_expect((x), 1)
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#define unlikely(x) __builtin_expect((x), 0)
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static const uint8_t duties[] = {
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0, 0, 0, 0, 0, 0, 0, 1,
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1, 0, 0, 0, 0, 0, 0, 1,
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1, 0, 0, 0, 0, 1, 1, 1,
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0, 1, 1, 1, 1, 1, 1, 0,
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};
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static void refresh_channel(GB_gameboy_t *gb, unsigned index, unsigned cycles_offset)
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{
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unsigned multiplier = gb->apu_output.cycles_since_render + cycles_offset - gb->apu_output.last_update[index];
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gb->apu_output.summed_samples[index].left += gb->apu_output.current_sample[index].left * multiplier;
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gb->apu_output.summed_samples[index].right += gb->apu_output.current_sample[index].right * multiplier;
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gb->apu_output.last_update[index] = gb->apu_output.cycles_since_render + cycles_offset;
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}
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bool GB_apu_is_DAC_enabled(GB_gameboy_t *gb, unsigned index)
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{
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if (gb->model >= GB_MODEL_AGB) {
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/* On the AGB, mixing is done digitally, so there are no per-channel
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DACs. Instead, all channels are summed digital regardless of
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whatever the DAC state would be on a CGB or earlier model. */
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return true;
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}
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switch (index) {
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case GB_SQUARE_1:
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return gb->io_registers[GB_IO_NR12] & 0xF8;
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case GB_SQUARE_2:
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return gb->io_registers[GB_IO_NR22] & 0xF8;
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case GB_WAVE:
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return gb->apu.wave_channel.enable;
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case GB_NOISE:
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return gb->io_registers[GB_IO_NR42] & 0xF8;
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}
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return false;
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}
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static uint8_t agb_bias_for_channel(GB_gameboy_t *gb, unsigned index)
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{
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if (!gb->apu.is_active[index]) return 0;
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switch (index) {
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case GB_SQUARE_1:
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return gb->apu.square_channels[GB_SQUARE_1].current_volume;
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case GB_SQUARE_2:
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return gb->apu.square_channels[GB_SQUARE_2].current_volume;
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case GB_WAVE:
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return 0;
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case GB_NOISE:
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return gb->apu.noise_channel.current_volume;
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}
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return 0;
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}
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static void update_sample(GB_gameboy_t *gb, unsigned index, int8_t value, unsigned cycles_offset)
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{
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if (gb->model >= GB_MODEL_AGB) {
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/* On the AGB, because no analog mixing is done, the behavior of NR51 is a bit different.
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A channel that is not connected to a terminal is idenitcal to a connected channel
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playing PCM sample 0. */
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gb->apu.samples[index] = value;
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if (gb->apu_output.sample_rate) {
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unsigned right_volume = (gb->io_registers[GB_IO_NR50] & 7) + 1;
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unsigned left_volume = ((gb->io_registers[GB_IO_NR50] >> 4) & 7) + 1;
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if (index == GB_WAVE) {
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/* For some reason, channel 3 is inverted on the AGB */
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value ^= 0xF;
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}
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GB_sample_t output;
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uint8_t bias = agb_bias_for_channel(gb, index);
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if (gb->io_registers[GB_IO_NR51] & (1 << index)) {
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output.right = (0xf - value * 2 + bias) * right_volume;
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}
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else {
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output.right = 0xf * right_volume;
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}
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if (gb->io_registers[GB_IO_NR51] & (0x10 << index)) {
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output.left = (0xf - value * 2 + bias) * left_volume;
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}
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else {
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output.left = 0xf * left_volume;
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}
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if (*(uint32_t *)&(gb->apu_output.current_sample[index]) != *(uint32_t *)&output) {
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refresh_channel(gb, index, cycles_offset);
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gb->apu_output.current_sample[index] = output;
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}
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}
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return;
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}
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if (!GB_apu_is_DAC_enabled(gb, index)) {
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value = gb->apu.samples[index];
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}
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else {
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gb->apu.samples[index] = value;
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}
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if (gb->apu_output.sample_rate) {
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unsigned right_volume = 0;
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if (gb->io_registers[GB_IO_NR51] & (1 << index)) {
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right_volume = (gb->io_registers[GB_IO_NR50] & 7) + 1;
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}
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unsigned left_volume = 0;
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if (gb->io_registers[GB_IO_NR51] & (0x10 << index)) {
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left_volume = ((gb->io_registers[GB_IO_NR50] >> 4) & 7) + 1;
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}
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GB_sample_t output = {(0xf - value * 2) * left_volume, (0xf - value * 2) * right_volume};
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if (*(uint32_t *)&(gb->apu_output.current_sample[index]) != *(uint32_t *)&output) {
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refresh_channel(gb, index, cycles_offset);
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gb->apu_output.current_sample[index] = output;
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}
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}
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}
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static double smooth(double x)
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{
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return 3*x*x - 2*x*x*x;
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}
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static signed interference(GB_gameboy_t *gb)
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{
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/* These aren't scientifically measured, but based on ear based on several recordings */
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signed ret = 0;
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if (gb->halted) {
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if (gb->model != GB_MODEL_AGB) {
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ret -= MAX_CH_AMP / 5;
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}
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else {
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ret -= MAX_CH_AMP / 12;
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}
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}
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if (gb->io_registers[GB_IO_LCDC] & 0x80) {
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ret += MAX_CH_AMP / 7;
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if ((gb->io_registers[GB_IO_STAT] & 3) == 3 && gb->model != GB_MODEL_AGB) {
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ret += MAX_CH_AMP / 14;
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}
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else if ((gb->io_registers[GB_IO_STAT] & 3) == 1) {
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ret -= MAX_CH_AMP / 7;
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}
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}
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if (gb->apu.global_enable) {
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ret += MAX_CH_AMP / 10;
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}
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if (GB_is_cgb(gb) && gb->model < GB_MODEL_AGB && (gb->io_registers[GB_IO_RP] & 1)) {
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ret += MAX_CH_AMP / 10;
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}
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if (!GB_is_cgb(gb)) {
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ret /= 4;
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}
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ret += rand() % (MAX_CH_AMP / 12);
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return ret;
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}
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static void render(GB_gameboy_t *gb)
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{
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GB_sample_t output = {0, 0};
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unrolled for (unsigned i = 0; i < GB_N_CHANNELS; i++) {
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double multiplier = CH_STEP;
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if (gb->model < GB_MODEL_AGB) {
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if (!GB_apu_is_DAC_enabled(gb, i)) {
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gb->apu_output.dac_discharge[i] -= ((double) DAC_DECAY_SPEED) / gb->apu_output.sample_rate;
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if (gb->apu_output.dac_discharge[i] < 0) {
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multiplier = 0;
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gb->apu_output.dac_discharge[i] = 0;
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}
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else {
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multiplier *= smooth(gb->apu_output.dac_discharge[i]);
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}
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}
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else {
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gb->apu_output.dac_discharge[i] += ((double) DAC_ATTACK_SPEED) / gb->apu_output.sample_rate;
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if (gb->apu_output.dac_discharge[i] > 1) {
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gb->apu_output.dac_discharge[i] = 1;
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}
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else {
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multiplier *= smooth(gb->apu_output.dac_discharge[i]);
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}
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}
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}
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if (likely(gb->apu_output.last_update[i] == 0)) {
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output.left += gb->apu_output.current_sample[i].left * multiplier;
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output.right += gb->apu_output.current_sample[i].right * multiplier;
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}
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else {
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refresh_channel(gb, i, 0);
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output.left += (signed long) gb->apu_output.summed_samples[i].left * multiplier
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/ gb->apu_output.cycles_since_render;
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output.right += (signed long) gb->apu_output.summed_samples[i].right * multiplier
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/ gb->apu_output.cycles_since_render;
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gb->apu_output.summed_samples[i] = (GB_sample_t){0, 0};
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}
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gb->apu_output.last_update[i] = 0;
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}
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gb->apu_output.cycles_since_render = 0;
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GB_sample_t filtered_output = gb->apu_output.highpass_mode?
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(GB_sample_t) {output.left - gb->apu_output.highpass_diff.left,
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output.right - gb->apu_output.highpass_diff.right} :
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output;
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switch (gb->apu_output.highpass_mode) {
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case GB_HIGHPASS_OFF:
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gb->apu_output.highpass_diff = (GB_double_sample_t) {0, 0};
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break;
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case GB_HIGHPASS_ACCURATE:
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gb->apu_output.highpass_diff = (GB_double_sample_t)
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{output.left - filtered_output.left * gb->apu_output.highpass_rate,
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output.right - filtered_output.right * gb->apu_output.highpass_rate};
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break;
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case GB_HIGHPASS_REMOVE_DC_OFFSET: {
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unsigned mask = gb->io_registers[GB_IO_NR51];
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unsigned left_volume = 0;
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unsigned right_volume = 0;
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unrolled for (unsigned i = GB_N_CHANNELS; i--;) {
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if (gb->apu.is_active[i]) {
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if (mask & 1) {
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left_volume += (gb->io_registers[GB_IO_NR50] & 7) * CH_STEP * 0xF;
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}
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if (mask & 0x10) {
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right_volume += ((gb->io_registers[GB_IO_NR50] >> 4) & 7) * CH_STEP * 0xF;
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}
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}
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else {
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left_volume += gb->apu_output.current_sample[i].left * CH_STEP;
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right_volume += gb->apu_output.current_sample[i].right * CH_STEP;
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}
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mask >>= 1;
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}
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gb->apu_output.highpass_diff = (GB_double_sample_t)
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{left_volume * (1 - gb->apu_output.highpass_rate) + gb->apu_output.highpass_diff.left * gb->apu_output.highpass_rate,
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right_volume * (1 - gb->apu_output.highpass_rate) + gb->apu_output.highpass_diff.right * gb->apu_output.highpass_rate};
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case GB_HIGHPASS_MAX:;
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}
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}
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if (gb->apu_output.interference_volume) {
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signed interference_bias = interference(gb);
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int16_t interference_sample = (interference_bias - gb->apu_output.interference_highpass);
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gb->apu_output.interference_highpass = gb->apu_output.interference_highpass * gb->apu_output.highpass_rate +
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(1 - gb->apu_output.highpass_rate) * interference_sample;
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interference_bias *= gb->apu_output.interference_volume;
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filtered_output.left = MAX(MIN(filtered_output.left + interference_bias, 0x7FFF), -0x8000);
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filtered_output.right = MAX(MIN(filtered_output.right + interference_bias, 0x7FFF), -0x8000);
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}
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assert(gb->apu_output.sample_callback);
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gb->apu_output.sample_callback(gb, &filtered_output);
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}
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static void update_square_sample(GB_gameboy_t *gb, unsigned index)
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{
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if (gb->apu.square_channels[index].current_sample_index & 0x80) return;
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uint8_t duty = gb->io_registers[index == GB_SQUARE_1? GB_IO_NR11 :GB_IO_NR21] >> 6;
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update_sample(gb, index,
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duties[gb->apu.square_channels[index].current_sample_index + duty * 8]?
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gb->apu.square_channels[index].current_volume : 0,
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0);
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}
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/* the effects of NRX2 writes on current volume are not well documented and differ
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between models and variants. The exact behavior can only be verified on CGB as it
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requires the PCM12 register. The behavior implemented here was verified on *my*
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CGB, which might behave differently from other CGB revisions, as well as from the
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DMG, MGB or SGB/2 */
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static void _nrx2_glitch(uint8_t *volume, uint8_t value, uint8_t old_value, uint8_t *countdown, GB_envelope_clock_t *lock)
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{
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if (lock->clock) {
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*countdown = value & 7;
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}
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bool should_tick = (value & 7) && !(old_value & 7) && !lock->locked;
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bool should_invert = (value & 8) ^ (old_value & 8);
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if ((value & 0xF) == 8 && (old_value & 0xF) == 8 && !lock->locked) {
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should_tick = true;
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}
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if (should_invert) {
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// The weird way and over-the-top way clocks for this counter are connected cause
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// some weird ways for it to invert
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if (value & 8) {
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if (!(old_value & 7) && !lock->locked) {
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*volume ^= 0xF;
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}
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else {
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*volume = 0xE - *volume;
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*volume &= 0xF;
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}
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should_tick = false; // Somehow prevents ticking?
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}
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else {
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*volume = 0x10 - *volume;
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*volume &= 0xF;
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}
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}
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if (should_tick) {
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if (value & 8) {
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(*volume)++;
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}
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else {
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(*volume)--;
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}
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*volume &= 0xF;
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}
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else if (!(value & 7) && lock->clock) {
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// *lock->locked = false; // Excepted from the schematics, but doesn't actually happen on any model?
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if (!should_invert) {
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if (*volume == 0xF && (value & 8)) {
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lock->locked = true;
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}
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else if (*volume == 0 && !(value & 8)) {
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lock->locked = true;
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}
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}
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else if (*volume == 1 && !(value & 8)) {
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lock->locked = true;
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}
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else if (*volume == 0xE && (value & 8)) {
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lock->locked = true;
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}
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lock->clock = false;
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}
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}
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static void nrx2_glitch(GB_gameboy_t *gb, uint8_t *volume, uint8_t value, uint8_t old_value, uint8_t *countdown, GB_envelope_clock_t *lock)
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{
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if (gb->model <= GB_MODEL_CGB_C) {
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_nrx2_glitch(volume, 0xFF, old_value, countdown, lock);
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_nrx2_glitch(volume, value, 0xFF, countdown, lock);
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}
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else {
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_nrx2_glitch(volume, value, old_value, countdown, lock);
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}
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}
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static void tick_square_envelope(GB_gameboy_t *gb, enum GB_CHANNELS index)
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{
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uint8_t nrx2 = gb->io_registers[index == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
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if (gb->apu.square_envelope_clock[index].locked) return;
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if (!(nrx2 & 7)) return;
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if (gb->cgb_double_speed) {
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if (index == GB_SQUARE_1) {
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gb->apu.pcm_mask[0] &= gb->apu.square_channels[GB_SQUARE_1].current_volume | 0xF1;
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}
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else {
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gb->apu.pcm_mask[0] &= (gb->apu.square_channels[GB_SQUARE_2].current_volume << 2) | 0x1F;
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}
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}
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if (nrx2 & 8) {
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if (gb->apu.square_channels[index].current_volume < 0xF) {
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gb->apu.square_channels[index].current_volume++;
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}
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else {
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gb->apu.square_envelope_clock[index].locked = true;
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}
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}
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else {
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if (gb->apu.square_channels[index].current_volume > 0) {
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gb->apu.square_channels[index].current_volume--;
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}
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else {
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gb->apu.square_envelope_clock[index].locked = true;
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}
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}
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if (gb->apu.is_active[index]) {
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update_square_sample(gb, index);
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}
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}
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static void tick_noise_envelope(GB_gameboy_t *gb)
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{
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uint8_t nr42 = gb->io_registers[GB_IO_NR42];
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if (gb->apu.noise_envelope_clock.locked) return;
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if (!(nr42 & 7)) return;
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if (gb->cgb_double_speed) {
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gb->apu.pcm_mask[0] &= (gb->apu.noise_channel.current_volume << 2) | 0x1F;
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}
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if (nr42 & 8) {
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if (gb->apu.noise_channel.current_volume < 0xF) {
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gb->apu.noise_channel.current_volume++;
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}
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else {
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gb->apu.noise_envelope_clock.locked = true;
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}
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}
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else {
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if (gb->apu.noise_channel.current_volume > 0) {
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gb->apu.noise_channel.current_volume--;
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}
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else {
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gb->apu.noise_envelope_clock.locked = true;
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}
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}
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if (gb->apu.is_active[GB_NOISE]) {
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update_sample(gb, GB_NOISE,
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(gb->apu.noise_channel.lfsr & 1) ?
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gb->apu.noise_channel.current_volume : 0,
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0);
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}
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}
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static void trigger_sweep_calculation(GB_gameboy_t *gb)
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{
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if ((gb->io_registers[GB_IO_NR10] & 0x70) && gb->apu.square_sweep_countdown == 7) {
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if (gb->io_registers[GB_IO_NR10] & 0x07) {
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gb->apu.square_channels[GB_SQUARE_1].sample_length =
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gb->apu.sweep_length_addend + gb->apu.shadow_sweep_sample_length + !!(gb->io_registers[GB_IO_NR10] & 0x8);
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gb->apu.square_channels[GB_SQUARE_1].sample_length &= 0x7FF;
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}
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if (gb->apu.channel_1_restart_hold == 0) {
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gb->apu.sweep_length_addend = gb->apu.square_channels[GB_SQUARE_1].sample_length;
|
|
gb->apu.sweep_length_addend >>= (gb->io_registers[GB_IO_NR10] & 7);
|
|
}
|
|
|
|
/* 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;
|
|
}
|
|
}
|
|
|
|
void GB_apu_div_event(GB_gameboy_t *gb)
|
|
{
|
|
if (!gb->apu.global_enable) return;
|
|
if (gb->apu.skip_div_event == GB_SKIP_DIV_EVENT_SKIP) {
|
|
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_SKIPPED;
|
|
return;
|
|
}
|
|
if (gb->apu.skip_div_event == GB_SKIP_DIV_EVENT_SKIPPED) {
|
|
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_INACTIVE;
|
|
}
|
|
else {
|
|
gb->apu.div_divider++;
|
|
}
|
|
|
|
if ((gb->apu.div_divider & 7) == 7) {
|
|
unrolled for (unsigned i = GB_SQUARE_2 + 1; i--;) {
|
|
if (!gb->apu.square_envelope_clock[i].clock) {
|
|
gb->apu.square_channels[i].volume_countdown--;
|
|
gb->apu.square_channels[i].volume_countdown &= 7;
|
|
}
|
|
}
|
|
if (!gb->apu.noise_envelope_clock.clock) {
|
|
gb->apu.noise_channel.volume_countdown--;
|
|
gb->apu.noise_channel.volume_countdown &= 7;
|
|
}
|
|
}
|
|
|
|
unrolled for (unsigned i = GB_SQUARE_2 + 1; i--;) {
|
|
if (gb->apu.square_envelope_clock[i].clock) {
|
|
tick_square_envelope(gb, i);
|
|
gb->apu.square_envelope_clock[i].clock = false;
|
|
}
|
|
}
|
|
|
|
if (gb->apu.noise_envelope_clock.clock) {
|
|
tick_noise_envelope(gb);
|
|
gb->apu.noise_envelope_clock.clock = false;
|
|
}
|
|
|
|
if ((gb->apu.div_divider & 1) == 1) {
|
|
unrolled for (unsigned i = GB_SQUARE_2 + 1; i--;) {
|
|
if (gb->apu.square_channels[i].length_enabled) {
|
|
if (gb->apu.square_channels[i].pulse_length) {
|
|
if (!--gb->apu.square_channels[i].pulse_length) {
|
|
gb->apu.is_active[i] = false;
|
|
update_sample(gb, i, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (gb->apu.wave_channel.length_enabled) {
|
|
if (gb->apu.wave_channel.pulse_length) {
|
|
if (!--gb->apu.wave_channel.pulse_length) {
|
|
gb->apu.is_active[GB_WAVE] = false;
|
|
update_sample(gb, GB_WAVE, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (gb->apu.noise_channel.length_enabled) {
|
|
if (gb->apu.noise_channel.pulse_length) {
|
|
if (!--gb->apu.noise_channel.pulse_length) {
|
|
gb->apu.is_active[GB_NOISE] = false;
|
|
update_sample(gb, GB_NOISE, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if ((gb->apu.div_divider & 3) == 3) {
|
|
gb->apu.square_sweep_countdown++;
|
|
gb->apu.square_sweep_countdown &= 7;
|
|
trigger_sweep_calculation(gb);
|
|
}
|
|
}
|
|
|
|
void GB_apu_div_secondary_event(GB_gameboy_t *gb)
|
|
{
|
|
unrolled for (unsigned i = GB_SQUARE_2 + 1; i--;) {
|
|
uint8_t nrx2 = gb->io_registers[i == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
|
|
if (gb->apu.is_active[i] && gb->apu.square_channels[i].volume_countdown == 0) {
|
|
gb->apu.square_envelope_clock[i].clock = (gb->apu.square_channels[i].volume_countdown = nrx2 & 7);
|
|
}
|
|
}
|
|
|
|
if (gb->apu.is_active[GB_NOISE] && gb->apu.noise_channel.volume_countdown == 0) {
|
|
gb->apu.noise_envelope_clock.clock = (gb->apu.noise_channel.volume_countdown = gb->io_registers[GB_IO_NR42] & 7);
|
|
}
|
|
}
|
|
|
|
static void step_lfsr(GB_gameboy_t *gb, unsigned cycles_offset)
|
|
{
|
|
unsigned high_bit_mask = gb->apu.noise_channel.narrow ? 0x4040 : 0x4000;
|
|
bool new_high_bit = (gb->apu.noise_channel.lfsr ^ (gb->apu.noise_channel.lfsr >> 1) ^ 1) & 1;
|
|
gb->apu.noise_channel.lfsr >>= 1;
|
|
|
|
if (new_high_bit) {
|
|
gb->apu.noise_channel.lfsr |= high_bit_mask;
|
|
}
|
|
else {
|
|
/* This code is not redundent, it's relevant when switching LFSR widths */
|
|
gb->apu.noise_channel.lfsr &= ~high_bit_mask;
|
|
}
|
|
|
|
gb->apu.current_lfsr_sample = gb->apu.noise_channel.lfsr & 1;
|
|
if (gb->apu.is_active[GB_NOISE]) {
|
|
update_sample(gb, GB_NOISE,
|
|
gb->apu.current_lfsr_sample ?
|
|
gb->apu.noise_channel.current_volume : 0,
|
|
cycles_offset);
|
|
}
|
|
}
|
|
|
|
void GB_apu_run(GB_gameboy_t *gb)
|
|
{
|
|
/* Convert 4MHZ to 2MHz. apu_cycles is always divisable by 4. */
|
|
uint8_t cycles = gb->apu.apu_cycles >> 2;
|
|
gb->apu.apu_cycles = 0;
|
|
if (!cycles) return;
|
|
|
|
bool start_ch4 = false;
|
|
if (likely(!gb->stopped || GB_is_cgb(gb))) {
|
|
if (gb->apu.channel_4_dmg_delayed_start) {
|
|
if (gb->apu.channel_4_dmg_delayed_start == cycles) {
|
|
gb->apu.channel_4_dmg_delayed_start = 0;
|
|
start_ch4 = true;
|
|
}
|
|
else if (gb->apu.channel_4_dmg_delayed_start > cycles) {
|
|
gb->apu.channel_4_dmg_delayed_start -= cycles;
|
|
}
|
|
else {
|
|
/* Split it into two */
|
|
cycles -= gb->apu.channel_4_dmg_delayed_start;
|
|
gb->apu.apu_cycles = gb->apu.channel_4_dmg_delayed_start * 4;
|
|
GB_apu_run(gb);
|
|
}
|
|
}
|
|
/* To align the square signal to 1MHz */
|
|
gb->apu.lf_div ^= cycles & 1;
|
|
gb->apu.noise_channel.alignment += cycles;
|
|
|
|
if (gb->apu.square_sweep_calculate_countdown &&
|
|
(((gb->io_registers[GB_IO_NR10] & 7) || gb->apu.unshifted_sweep) ||
|
|
gb->apu.square_sweep_calculate_countdown <= 3)) { // Calculation is paused if the lower bits are 0
|
|
if (gb->apu.square_sweep_calculate_countdown > cycles) {
|
|
gb->apu.square_sweep_calculate_countdown -= cycles;
|
|
}
|
|
else {
|
|
/* APU bug: sweep frequency is checked after adding the sweep delta twice */
|
|
if (gb->apu.channel_1_restart_hold == 0) {
|
|
gb->apu.shadow_sweep_sample_length = gb->apu.square_channels[GB_SQUARE_1].sample_length;
|
|
}
|
|
if (gb->io_registers[GB_IO_NR10] & 8) {
|
|
gb->apu.sweep_length_addend ^= 0x7FF;
|
|
}
|
|
if (gb->apu.shadow_sweep_sample_length + gb->apu.sweep_length_addend > 0x7FF && !(gb->io_registers[GB_IO_NR10] & 8)) {
|
|
gb->apu.is_active[GB_SQUARE_1] = false;
|
|
update_sample(gb, GB_SQUARE_1, 0, gb->apu.square_sweep_calculate_countdown - cycles);
|
|
}
|
|
gb->apu.channel1_completed_addend = gb->apu.sweep_length_addend;
|
|
|
|
gb->apu.square_sweep_calculate_countdown = 0;
|
|
}
|
|
}
|
|
|
|
if (gb->apu.channel_1_restart_hold) {
|
|
if (gb->apu.channel_1_restart_hold > cycles) {
|
|
gb->apu.channel_1_restart_hold -= cycles;
|
|
}
|
|
else {
|
|
gb->apu.channel_1_restart_hold = 0;
|
|
}
|
|
}
|
|
|
|
unrolled for (unsigned i = GB_SQUARE_1; i <= GB_SQUARE_2; i++) {
|
|
if (gb->apu.is_active[i]) {
|
|
uint8_t cycles_left = cycles;
|
|
while (unlikely(cycles_left > gb->apu.square_channels[i].sample_countdown)) {
|
|
cycles_left -= gb->apu.square_channels[i].sample_countdown + 1;
|
|
gb->apu.square_channels[i].sample_countdown = (gb->apu.square_channels[i].sample_length ^ 0x7FF) * 2 + 1;
|
|
gb->apu.square_channels[i].current_sample_index++;
|
|
gb->apu.square_channels[i].current_sample_index &= 0x7;
|
|
if (cycles_left == 0 && gb->apu.samples[i] == 0) {
|
|
gb->apu.pcm_mask[0] &= i == GB_SQUARE_1? 0xF0 : 0x0F;
|
|
}
|
|
|
|
update_square_sample(gb, i);
|
|
}
|
|
if (cycles_left) {
|
|
gb->apu.square_channels[i].sample_countdown -= cycles_left;
|
|
}
|
|
}
|
|
}
|
|
|
|
gb->apu.wave_channel.wave_form_just_read = false;
|
|
if (gb->apu.is_active[GB_WAVE]) {
|
|
uint8_t cycles_left = cycles;
|
|
while (unlikely(cycles_left > gb->apu.wave_channel.sample_countdown)) {
|
|
cycles_left -= gb->apu.wave_channel.sample_countdown + 1;
|
|
gb->apu.wave_channel.sample_countdown = gb->apu.wave_channel.sample_length ^ 0x7FF;
|
|
gb->apu.wave_channel.current_sample_index++;
|
|
gb->apu.wave_channel.current_sample_index &= 0x1F;
|
|
gb->apu.wave_channel.current_sample =
|
|
gb->apu.wave_channel.wave_form[gb->apu.wave_channel.current_sample_index];
|
|
update_sample(gb, GB_WAVE,
|
|
gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift,
|
|
cycles - cycles_left);
|
|
gb->apu.wave_channel.wave_form_just_read = true;
|
|
}
|
|
if (cycles_left) {
|
|
gb->apu.wave_channel.sample_countdown -= cycles_left;
|
|
gb->apu.wave_channel.wave_form_just_read = false;
|
|
}
|
|
}
|
|
|
|
// The noise channel can step even if inactive on the DMG
|
|
if (gb->apu.is_active[GB_NOISE] || !GB_is_cgb(gb)) {
|
|
uint8_t cycles_left = cycles;
|
|
unsigned divisor = (gb->io_registers[GB_IO_NR43] & 0x07) << 2;
|
|
if (!divisor) divisor = 2;
|
|
if (gb->apu.noise_channel.counter_countdown == 0) {
|
|
gb->apu.noise_channel.counter_countdown = divisor;
|
|
}
|
|
while (unlikely(cycles_left >= gb->apu.noise_channel.counter_countdown)) {
|
|
cycles_left -= gb->apu.noise_channel.counter_countdown;
|
|
gb->apu.noise_channel.counter_countdown = divisor + gb->apu.channel_4_delta;
|
|
gb->apu.channel_4_delta = 0;
|
|
bool old_bit = (gb->apu.noise_channel.counter >> (gb->io_registers[GB_IO_NR43] >> 4)) & 1;
|
|
gb->apu.noise_channel.counter++;
|
|
gb->apu.noise_channel.counter &= 0x3FFF;
|
|
bool new_bit = (gb->apu.noise_channel.counter >> (gb->io_registers[GB_IO_NR43] >> 4)) & 1;
|
|
|
|
/* Step LFSR */
|
|
if (new_bit && !old_bit) {
|
|
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) {
|
|
gb->apu.noise_channel.counter_countdown -= cycles_left;
|
|
gb->apu.channel_4_countdown_reloaded = false;
|
|
}
|
|
else {
|
|
gb->apu.channel_4_countdown_reloaded = true;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (gb->apu_output.sample_rate) {
|
|
gb->apu_output.cycles_since_render += cycles;
|
|
|
|
if (gb->apu_output.sample_cycles >= gb->apu_output.cycles_per_sample) {
|
|
gb->apu_output.sample_cycles -= gb->apu_output.cycles_per_sample;
|
|
render(gb);
|
|
}
|
|
}
|
|
if (start_ch4) {
|
|
GB_apu_write(gb, GB_IO_NR44, gb->io_registers[GB_IO_NR44] | 0x80);
|
|
}
|
|
}
|
|
|
|
void GB_apu_init(GB_gameboy_t *gb)
|
|
{
|
|
memset(&gb->apu, 0, sizeof(gb->apu));
|
|
/* Restore the wave form */
|
|
for (unsigned reg = GB_IO_WAV_START; reg <= GB_IO_WAV_END; reg++) {
|
|
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2] = gb->io_registers[reg] >> 4;
|
|
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2 + 1] = gb->io_registers[reg] & 0xF;
|
|
}
|
|
gb->apu.lf_div = 1;
|
|
gb->apu.wave_channel.shift = 4;
|
|
/* APU glitch: When turning the APU on while DIV's bit 4 (or 5 in double speed mode) is on,
|
|
the first DIV/APU event is skipped. */
|
|
if (gb->div_counter & (gb->cgb_double_speed? 0x2000 : 0x1000)) {
|
|
gb->apu.skip_div_event = GB_SKIP_DIV_EVENT_SKIP;
|
|
gb->apu.div_divider = 1;
|
|
}
|
|
}
|
|
|
|
uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg)
|
|
{
|
|
if (reg == GB_IO_NR52) {
|
|
uint8_t value = 0;
|
|
for (unsigned i = 0; i < GB_N_CHANNELS; i++) {
|
|
value >>= 1;
|
|
if (gb->apu.is_active[i]) {
|
|
value |= 0x8;
|
|
}
|
|
}
|
|
if (gb->apu.global_enable) {
|
|
value |= 0x80;
|
|
}
|
|
value |= 0x70;
|
|
return value;
|
|
}
|
|
|
|
static const char read_mask[GB_IO_WAV_END - GB_IO_NR10 + 1] = {
|
|
/* NRX0 NRX1 NRX2 NRX3 NRX4 */
|
|
0x80, 0x3F, 0x00, 0xFF, 0xBF, // NR1X
|
|
0xFF, 0x3F, 0x00, 0xFF, 0xBF, // NR2X
|
|
0x7F, 0xFF, 0x9F, 0xFF, 0xBF, // NR3X
|
|
0xFF, 0xFF, 0x00, 0x00, 0xBF, // NR4X
|
|
0x00, 0x00, 0x70, 0xFF, 0xFF, // NR5X
|
|
|
|
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, // Unused
|
|
// Wave RAM
|
|
0, /* ... */
|
|
};
|
|
|
|
if (reg >= GB_IO_WAV_START && reg <= GB_IO_WAV_END && gb->apu.is_active[GB_WAVE]) {
|
|
if (!GB_is_cgb(gb) && !gb->apu.wave_channel.wave_form_just_read) {
|
|
return 0xFF;
|
|
}
|
|
if (gb->model == GB_MODEL_AGB) {
|
|
return 0xFF;
|
|
}
|
|
reg = GB_IO_WAV_START + gb->apu.wave_channel.current_sample_index / 2;
|
|
}
|
|
|
|
return gb->io_registers[reg] | read_mask[reg - GB_IO_NR10];
|
|
}
|
|
|
|
static inline uint16_t effective_channel4_counter(GB_gameboy_t *gb)
|
|
{
|
|
/*
|
|
TODO: On revisions older than the CGB-D, this behaves differently when
|
|
the counter advanced this exact T-cycle. Also, in these revisions,
|
|
it seems that "passive" changes (due to the temporary FF value NR43
|
|
has during writes) behave slightly different from non-passive ones.
|
|
*/
|
|
uint16_t effective_counter = gb->apu.noise_channel.counter;
|
|
/* Ladies and gentlemen, I present you the holy grail glitch of revision detection! */
|
|
switch (gb->model) {
|
|
/* Pre CGB revisions are assumed to be like CGB-C, A and 0 for the lack of a better guess.
|
|
TODO: It could be verified with audio based test ROMs. */
|
|
#if 0
|
|
case GB_MODEL_CGB_B:
|
|
if (effective_counter & 8) {
|
|
effective_counter |= 0xE; // Seems to me F under some circumstances?
|
|
}
|
|
if (effective_counter & 0x80) {
|
|
effective_counter |= 0xFF;
|
|
}
|
|
if (effective_counter & 0x100) {
|
|
effective_counter |= 0x1;
|
|
}
|
|
if (effective_counter & 0x200) {
|
|
effective_counter |= 0x2;
|
|
}
|
|
if (effective_counter & 0x400) {
|
|
effective_counter |= 0x4;
|
|
}
|
|
if (effective_counter & 0x800) {
|
|
effective_counter |= 0x408; // TODO: Only my CGB-B does that! Others behave like C!
|
|
}
|
|
if (effective_counter & 0x1000) {
|
|
effective_counter |= 0x10;
|
|
}
|
|
if (effective_counter & 0x2000) {
|
|
effective_counter |= 0x20;
|
|
}
|
|
break;
|
|
#endif
|
|
case GB_MODEL_DMG_B:
|
|
case GB_MODEL_SGB_NTSC:
|
|
case GB_MODEL_SGB_PAL:
|
|
case GB_MODEL_SGB_NTSC_NO_SFC:
|
|
case GB_MODEL_SGB_PAL_NO_SFC:
|
|
case GB_MODEL_SGB2:
|
|
case GB_MODEL_SGB2_NO_SFC:
|
|
// case GB_MODEL_CGB_0:
|
|
// case GB_MODEL_CGB_A:
|
|
case GB_MODEL_CGB_C:
|
|
if (effective_counter & 8) {
|
|
effective_counter |= 0xE; // Sometimes F on some instances
|
|
}
|
|
if (effective_counter & 0x80) {
|
|
effective_counter |= 0xFF;
|
|
}
|
|
if (effective_counter & 0x100) {
|
|
effective_counter |= 0x1;
|
|
}
|
|
if (effective_counter & 0x200) {
|
|
effective_counter |= 0x2;
|
|
}
|
|
if (effective_counter & 0x400) {
|
|
effective_counter |= 0x4;
|
|
}
|
|
if (effective_counter & 0x800) {
|
|
if ((gb->io_registers[GB_IO_NR43] & 8)) {
|
|
effective_counter |= 0x400;
|
|
}
|
|
effective_counter |= 0x8;
|
|
}
|
|
if (effective_counter & 0x1000) {
|
|
effective_counter |= 0x10;
|
|
}
|
|
if (effective_counter & 0x2000) {
|
|
effective_counter |= 0x20;
|
|
}
|
|
break;
|
|
#if 0
|
|
case GB_MODEL_CGB_D:
|
|
if (effective_counter & ((gb->io_registers[GB_IO_NR43] & 8)? 0x40 : 0x80)) { // This is so weird
|
|
effective_counter |= 0xFF;
|
|
}
|
|
if (effective_counter & 0x100) {
|
|
effective_counter |= 0x1;
|
|
}
|
|
if (effective_counter & 0x200) {
|
|
effective_counter |= 0x2;
|
|
}
|
|
if (effective_counter & 0x400) {
|
|
effective_counter |= 0x4;
|
|
}
|
|
if (effective_counter & 0x800) {
|
|
effective_counter |= 0x8;
|
|
}
|
|
if (effective_counter & 0x1000) {
|
|
effective_counter |= 0x10;
|
|
}
|
|
break;
|
|
#endif
|
|
case GB_MODEL_CGB_E:
|
|
if (effective_counter & ((gb->io_registers[GB_IO_NR43] & 8)? 0x40 : 0x80)) { // This is so weird
|
|
effective_counter |= 0xFF;
|
|
}
|
|
if (effective_counter & 0x1000) {
|
|
effective_counter |= 0x10;
|
|
}
|
|
break;
|
|
case GB_MODEL_AGB:
|
|
/* TODO: AGBs are not affected, but AGSes are. They don't seem to follow a simple
|
|
pattern like the other revisions. */
|
|
/* For the most part, AGS seems to do:
|
|
0x20 -> 0xA0
|
|
0x200 -> 0xA00
|
|
0x1000 -> 0x1010, but only if wide
|
|
*/
|
|
break;
|
|
}
|
|
return effective_counter;
|
|
}
|
|
|
|
void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value)
|
|
{
|
|
if (!gb->apu.global_enable && reg != GB_IO_NR52 && reg < GB_IO_WAV_START && (GB_is_cgb(gb) ||
|
|
(
|
|
reg != GB_IO_NR11 &&
|
|
reg != GB_IO_NR21 &&
|
|
reg != GB_IO_NR31 &&
|
|
reg != GB_IO_NR41
|
|
)
|
|
)) {
|
|
return;
|
|
}
|
|
|
|
if (reg >= GB_IO_WAV_START && reg <= GB_IO_WAV_END && gb->apu.is_active[GB_WAVE]) {
|
|
if ((!GB_is_cgb(gb) && !gb->apu.wave_channel.wave_form_just_read) || gb->model == GB_MODEL_AGB) {
|
|
return;
|
|
}
|
|
reg = GB_IO_WAV_START + gb->apu.wave_channel.current_sample_index / 2;
|
|
}
|
|
|
|
/* Todo: this can and should be rewritten with a function table. */
|
|
switch (reg) {
|
|
/* Globals */
|
|
case GB_IO_NR50:
|
|
case GB_IO_NR51:
|
|
gb->io_registers[reg] = value;
|
|
/* These registers affect the output of all 4 channels (but not the output of the PCM registers).*/
|
|
/* We call update_samples with the current value so the APU output is updated with the new outputs */
|
|
for (unsigned i = GB_N_CHANNELS; i--;) {
|
|
update_sample(gb, i, gb->apu.samples[i], 0);
|
|
}
|
|
break;
|
|
case GB_IO_NR52: {
|
|
|
|
uint8_t old_pulse_lengths[] = {
|
|
gb->apu.square_channels[0].pulse_length,
|
|
gb->apu.square_channels[1].pulse_length,
|
|
gb->apu.wave_channel.pulse_length,
|
|
gb->apu.noise_channel.pulse_length
|
|
};
|
|
if ((value & 0x80) && !gb->apu.global_enable) {
|
|
GB_apu_init(gb);
|
|
gb->apu.global_enable = true;
|
|
}
|
|
else if (!(value & 0x80) && gb->apu.global_enable) {
|
|
for (unsigned i = GB_N_CHANNELS; i--;) {
|
|
update_sample(gb, i, 0, 0);
|
|
}
|
|
memset(&gb->apu, 0, sizeof(gb->apu));
|
|
memset(gb->io_registers + GB_IO_NR10, 0, GB_IO_WAV_START - GB_IO_NR10);
|
|
gb->apu.global_enable = false;
|
|
}
|
|
|
|
if (!GB_is_cgb(gb) && (value & 0x80)) {
|
|
gb->apu.square_channels[0].pulse_length = old_pulse_lengths[0];
|
|
gb->apu.square_channels[1].pulse_length = old_pulse_lengths[1];
|
|
gb->apu.wave_channel.pulse_length = old_pulse_lengths[2];
|
|
gb->apu.noise_channel.pulse_length = old_pulse_lengths[3];
|
|
}
|
|
}
|
|
break;
|
|
|
|
/* Square channels */
|
|
case GB_IO_NR10:{
|
|
bool old_negate = gb->io_registers[GB_IO_NR10] & 8;
|
|
gb->io_registers[GB_IO_NR10] = value;
|
|
if (gb->apu.shadow_sweep_sample_length + gb->apu.channel1_completed_addend + old_negate > 0x7FF &&
|
|
!(value & 8)) {
|
|
gb->apu.is_active[GB_SQUARE_1] = false;
|
|
update_sample(gb, GB_SQUARE_1, 0, 0);
|
|
}
|
|
trigger_sweep_calculation(gb);
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR11:
|
|
case GB_IO_NR21: {
|
|
unsigned index = reg == GB_IO_NR21? GB_SQUARE_2: GB_SQUARE_1;
|
|
gb->apu.square_channels[index].pulse_length = (0x40 - (value & 0x3f));
|
|
if (!gb->apu.global_enable) {
|
|
value &= 0x3f;
|
|
}
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR12:
|
|
case GB_IO_NR22: {
|
|
unsigned index = reg == GB_IO_NR22? GB_SQUARE_2: GB_SQUARE_1;
|
|
if ((value & 0xF8) == 0) {
|
|
/* This disables the DAC */
|
|
gb->io_registers[reg] = value;
|
|
gb->apu.is_active[index] = false;
|
|
update_sample(gb, index, 0, 0);
|
|
}
|
|
else if (gb->apu.is_active[index]) {
|
|
nrx2_glitch(gb, &gb->apu.square_channels[index].current_volume,
|
|
value, gb->io_registers[reg], &gb->apu.square_channels[index].volume_countdown,
|
|
&gb->apu.square_envelope_clock[index]);
|
|
update_square_sample(gb, index);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR13:
|
|
case GB_IO_NR23: {
|
|
unsigned index = reg == GB_IO_NR23? GB_SQUARE_2: GB_SQUARE_1;
|
|
gb->apu.square_channels[index].sample_length &= ~0xFF;
|
|
gb->apu.square_channels[index].sample_length |= value & 0xFF;
|
|
break;
|
|
}
|
|
|
|
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
|
|
old length, but the current sample should not change. Because our write timing isn't accurate to
|
|
the T-cycle, we hack around it by stepping the sample index backwards. */
|
|
if ((value & 0x80) == 0 && gb->apu.is_active[index]) {
|
|
/* On an AGB, as well as on CGB C and earlier (TODO: Tested: 0, B and C), it behaves slightly different on
|
|
double speed. */
|
|
if (gb->model == GB_MODEL_CGB_E /* || gb->model == GB_MODEL_CGB_D */ || gb->apu.square_channels[index].sample_countdown & 1) {
|
|
if (gb->apu.square_channels[index].sample_countdown >> 1 == (gb->apu.square_channels[index].sample_length ^ 0x7FF)) {
|
|
gb->apu.square_channels[index].current_sample_index--;
|
|
gb->apu.square_channels[index].current_sample_index &= 7;
|
|
}
|
|
}
|
|
}
|
|
|
|
uint16_t old_sample_length = gb->apu.square_channels[index].sample_length;
|
|
gb->apu.square_channels[index].sample_length &= 0xFF;
|
|
gb->apu.square_channels[index].sample_length |= (value & 7) << 8;
|
|
if (value & 0x80) {
|
|
/* Current sample index remains unchanged when restarting channels 1 or 2. It is only reset by
|
|
turning the APU off. */
|
|
gb->apu.square_envelope_clock[index].locked = false;
|
|
gb->apu.square_envelope_clock[index].clock = false;
|
|
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;
|
|
if (gb->model == GB_MODEL_CGB_E /* || gb->model == GB_MODEL_CGB_D */) {
|
|
if (!(value & 4) && !(((gb->apu.square_channels[index].sample_countdown - 1) / 2) & 0x400)) {
|
|
gb->apu.square_channels[index].current_sample_index++;
|
|
gb->apu.square_channels[index].current_sample_index &= 0x7;
|
|
}
|
|
/* Todo: verify with the schematics what's going on in here */
|
|
else if (gb->apu.square_channels[index].sample_length == 0x7FF &&
|
|
old_sample_length != 0x7FF &&
|
|
(gb->apu.square_channels[index].current_sample_index & 0x80)) {
|
|
extra_delay += 2;
|
|
}
|
|
}
|
|
/* 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;
|
|
/* The volume changes caused by NRX4 sound start take effect instantly (i.e. the effect the previously
|
|
started sound). The playback itself is not instant which is why we don't update the sample for other
|
|
cases. */
|
|
if (gb->apu.is_active[index]) {
|
|
update_square_sample(gb, index);
|
|
}
|
|
|
|
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]) {
|
|
gb->apu.is_active[index] = true;
|
|
update_sample(gb, index, 0, 0);
|
|
/* We use the highest bit in current_sample_index to mark this sample is not actually playing yet, */
|
|
gb->apu.square_channels[index].current_sample_index |= 0x80;
|
|
}
|
|
if (gb->apu.square_channels[index].pulse_length == 0) {
|
|
gb->apu.square_channels[index].pulse_length = 0x40;
|
|
gb->apu.square_channels[index].length_enabled = false;
|
|
}
|
|
|
|
if (index == GB_SQUARE_1) {
|
|
gb->apu.shadow_sweep_sample_length = 0;
|
|
gb->apu.channel1_completed_addend = 0;
|
|
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) {
|
|
/* TODO: I used to think this is correct, but it caused several regressions.
|
|
More research is needed to figure how calculation time is different
|
|
in models prior to CGB-D */
|
|
// gb->apu.square_sweep_calculate_countdown += 2;
|
|
}
|
|
gb->apu.enable_zombie_calculate_stepping = false;
|
|
gb->apu.unshifted_sweep = false;
|
|
if (!was_active) {
|
|
gb->apu.square_sweep_calculate_countdown += 2;
|
|
}
|
|
gb->apu.sweep_length_addend = gb->apu.square_channels[GB_SQUARE_1].sample_length;
|
|
gb->apu.sweep_length_addend >>= (gb->io_registers[GB_IO_NR10] & 7);
|
|
}
|
|
else {
|
|
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;
|
|
}
|
|
}
|
|
|
|
/* APU glitch - if length is enabled while the DIV-divider's LSB is 1, tick the length once. */
|
|
if ((value & 0x40) &&
|
|
!gb->apu.square_channels[index].length_enabled &&
|
|
(gb->apu.div_divider & 1) &&
|
|
gb->apu.square_channels[index].pulse_length) {
|
|
gb->apu.square_channels[index].pulse_length--;
|
|
if (gb->apu.square_channels[index].pulse_length == 0) {
|
|
if (value & 0x80) {
|
|
gb->apu.square_channels[index].pulse_length = 0x3F;
|
|
}
|
|
else {
|
|
gb->apu.is_active[index] = false;
|
|
update_sample(gb, index, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
gb->apu.square_channels[index].length_enabled = value & 0x40;
|
|
break;
|
|
}
|
|
|
|
/* Wave channel */
|
|
case GB_IO_NR30:
|
|
gb->apu.wave_channel.enable = value & 0x80;
|
|
if (!gb->apu.wave_channel.enable) {
|
|
gb->apu.is_active[GB_WAVE] = false;
|
|
update_sample(gb, GB_WAVE, 0, 0);
|
|
}
|
|
break;
|
|
case GB_IO_NR31:
|
|
gb->apu.wave_channel.pulse_length = (0x100 - value);
|
|
break;
|
|
case GB_IO_NR32:
|
|
gb->apu.wave_channel.shift = (uint8_t[]){4, 0, 1, 2}[(value >> 5) & 3];
|
|
if (gb->apu.is_active[GB_WAVE]) {
|
|
update_sample(gb, GB_WAVE, gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift, 0);
|
|
}
|
|
break;
|
|
case GB_IO_NR33:
|
|
gb->apu.wave_channel.sample_length &= ~0xFF;
|
|
gb->apu.wave_channel.sample_length |= value & 0xFF;
|
|
break;
|
|
case GB_IO_NR34:
|
|
gb->apu.wave_channel.sample_length &= 0xFF;
|
|
gb->apu.wave_channel.sample_length |= (value & 7) << 8;
|
|
if (value & 0x80) {
|
|
/* DMG bug: wave RAM gets corrupted if the channel is retriggerred 1 cycle before the APU
|
|
reads from it. */
|
|
if (!GB_is_cgb(gb) &&
|
|
gb->apu.is_active[GB_WAVE] &&
|
|
gb->apu.wave_channel.sample_countdown == 0) {
|
|
unsigned offset = ((gb->apu.wave_channel.current_sample_index + 1) >> 1) & 0xF;
|
|
|
|
/* This glitch varies between models and even specific instances:
|
|
DMG-B: Most of them behave as emulated. A few behave differently.
|
|
SGB: As far as I know, all tested instances behave as emulated.
|
|
MGB, SGB2: Most instances behave non-deterministically, a few behave as emulated.
|
|
|
|
Additionally, I believe DMGs, including those we behave differently than emulated,
|
|
are all deterministic. */
|
|
if (offset < 4) {
|
|
gb->io_registers[GB_IO_WAV_START] = gb->io_registers[GB_IO_WAV_START + offset];
|
|
gb->apu.wave_channel.wave_form[0] = gb->apu.wave_channel.wave_form[offset / 2];
|
|
gb->apu.wave_channel.wave_form[1] = gb->apu.wave_channel.wave_form[offset / 2 + 1];
|
|
}
|
|
else {
|
|
memcpy(gb->io_registers + GB_IO_WAV_START,
|
|
gb->io_registers + GB_IO_WAV_START + (offset & ~3),
|
|
4);
|
|
memcpy(gb->apu.wave_channel.wave_form,
|
|
gb->apu.wave_channel.wave_form + (offset & ~3) * 2,
|
|
8);
|
|
}
|
|
}
|
|
if (!gb->apu.is_active[GB_WAVE] && gb->apu.wave_channel.enable) {
|
|
gb->apu.is_active[GB_WAVE] = true;
|
|
update_sample(gb, GB_WAVE,
|
|
gb->apu.wave_channel.current_sample >> gb->apu.wave_channel.shift,
|
|
0);
|
|
}
|
|
gb->apu.wave_channel.sample_countdown = (gb->apu.wave_channel.sample_length ^ 0x7FF) + 3;
|
|
gb->apu.wave_channel.current_sample_index = 0;
|
|
if (gb->apu.wave_channel.pulse_length == 0) {
|
|
gb->apu.wave_channel.pulse_length = 0x100;
|
|
gb->apu.wave_channel.length_enabled = false;
|
|
}
|
|
/* Note that we don't change the sample just yet! This was verified on hardware. */
|
|
}
|
|
|
|
/* APU glitch - if length is enabled while the DIV-divider's LSB is 1, tick the length once. */
|
|
if ((value & 0x40) &&
|
|
!gb->apu.wave_channel.length_enabled &&
|
|
(gb->apu.div_divider & 1) &&
|
|
gb->apu.wave_channel.pulse_length) {
|
|
gb->apu.wave_channel.pulse_length--;
|
|
if (gb->apu.wave_channel.pulse_length == 0) {
|
|
if (value & 0x80) {
|
|
gb->apu.wave_channel.pulse_length = 0xFF;
|
|
}
|
|
else {
|
|
gb->apu.is_active[GB_WAVE] = false;
|
|
update_sample(gb, GB_WAVE, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
gb->apu.wave_channel.length_enabled = value & 0x40;
|
|
|
|
break;
|
|
|
|
/* Noise Channel */
|
|
|
|
case GB_IO_NR41: {
|
|
gb->apu.noise_channel.pulse_length = (0x40 - (value & 0x3f));
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR42: {
|
|
if ((value & 0xF8) == 0) {
|
|
/* This disables the DAC */
|
|
gb->io_registers[reg] = value;
|
|
gb->apu.is_active[GB_NOISE] = false;
|
|
update_sample(gb, GB_NOISE, 0, 0);
|
|
}
|
|
else if (gb->apu.is_active[GB_NOISE]) {
|
|
nrx2_glitch(gb, &gb->apu.noise_channel.current_volume,
|
|
value, gb->io_registers[reg], &gb->apu.noise_channel.volume_countdown,
|
|
&gb->apu.noise_envelope_clock);
|
|
update_sample(gb, GB_NOISE,
|
|
gb->apu.current_lfsr_sample ?
|
|
gb->apu.noise_channel.current_volume : 0,
|
|
0);
|
|
}
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR43: {
|
|
gb->apu.noise_channel.narrow = value & 8;
|
|
uint16_t effective_counter = effective_channel4_counter(gb);
|
|
bool old_bit = (effective_counter >> (gb->io_registers[GB_IO_NR43] >> 4)) & 1;
|
|
gb->io_registers[GB_IO_NR43] = value;
|
|
bool new_bit = (effective_counter >> (gb->io_registers[GB_IO_NR43] >> 4)) & 1;
|
|
if (gb->apu.channel_4_countdown_reloaded) {
|
|
unsigned divisor = (gb->io_registers[GB_IO_NR43] & 0x07) << 2;
|
|
if (!divisor) divisor = 2;
|
|
if (gb->model > GB_MODEL_CGB_C) {
|
|
gb->apu.noise_channel.counter_countdown =
|
|
divisor + (divisor == 2? 0 : (uint8_t[]){2, 1, 0, 3}[(gb->apu.noise_channel.alignment) & 3]);
|
|
}
|
|
else {
|
|
gb->apu.noise_channel.counter_countdown =
|
|
divisor + (divisor == 2? 0 : (uint8_t[]){2, 1, 4, 3}[(gb->apu.noise_channel.alignment) & 3]);
|
|
}
|
|
gb->apu.channel_4_delta = 0;
|
|
}
|
|
/* Step LFSR */
|
|
if (new_bit && (!old_bit || gb->model <= GB_MODEL_CGB_C)) {
|
|
if (gb->model <= GB_MODEL_CGB_C) {
|
|
bool previous_narrow = gb->apu.noise_channel.narrow;
|
|
gb->apu.noise_channel.narrow = true;
|
|
step_lfsr(gb, 0);
|
|
gb->apu.noise_channel.narrow = previous_narrow;
|
|
}
|
|
else {
|
|
step_lfsr(gb, 0);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case GB_IO_NR44: {
|
|
if (value & 0x80) {
|
|
gb->apu.noise_envelope_clock.locked = false;
|
|
gb->apu.noise_envelope_clock.clock = false;
|
|
if (!GB_is_cgb(gb) && (gb->apu.noise_channel.alignment & 3) != 0) {
|
|
gb->apu.channel_4_dmg_delayed_start = 6;
|
|
}
|
|
else {
|
|
unsigned divisor = (gb->io_registers[GB_IO_NR43] & 0x07) << 2;
|
|
if (!divisor) divisor = 2;
|
|
gb->apu.channel_4_delta = 0;
|
|
gb->apu.noise_channel.counter_countdown = divisor + 4;
|
|
if (divisor == 2) {
|
|
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 {
|
|
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;
|
|
gb->apu.channel_4_delta = 2;
|
|
}
|
|
else {
|
|
gb->apu.noise_channel.counter_countdown -= 4;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* TODO: These are quite weird. Verify further */
|
|
if (gb->model <= GB_MODEL_CGB_C) {
|
|
if (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;
|
|
}
|
|
}
|
|
else {
|
|
gb->apu.noise_channel.counter_countdown -= 2;
|
|
}
|
|
}
|
|
|
|
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
|
|
started sound). The playback itself is not instant which is why we don't update the sample for other
|
|
cases. */
|
|
if (gb->apu.is_active[GB_NOISE]) {
|
|
update_sample(gb, GB_NOISE,
|
|
gb->apu.current_lfsr_sample ?
|
|
gb->apu.noise_channel.current_volume : 0,
|
|
0);
|
|
}
|
|
gb->apu.noise_channel.lfsr = 0;
|
|
gb->apu.current_lfsr_sample = false;
|
|
gb->apu.noise_channel.volume_countdown = gb->io_registers[GB_IO_NR42] & 7;
|
|
|
|
if (!gb->apu.is_active[GB_NOISE] && (gb->io_registers[GB_IO_NR42] & 0xF8) != 0) {
|
|
gb->apu.is_active[GB_NOISE] = true;
|
|
update_sample(gb, GB_NOISE, 0, 0);
|
|
}
|
|
|
|
if (gb->apu.noise_channel.pulse_length == 0) {
|
|
gb->apu.noise_channel.pulse_length = 0x40;
|
|
gb->apu.noise_channel.length_enabled = false;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* APU glitch - if length is enabled while the DIV-divider's LSB is 1, tick the length once. */
|
|
if ((value & 0x40) &&
|
|
!gb->apu.noise_channel.length_enabled &&
|
|
(gb->apu.div_divider & 1) &&
|
|
gb->apu.noise_channel.pulse_length) {
|
|
gb->apu.noise_channel.pulse_length--;
|
|
if (gb->apu.noise_channel.pulse_length == 0) {
|
|
if (value & 0x80) {
|
|
gb->apu.noise_channel.pulse_length = 0x3F;
|
|
}
|
|
else {
|
|
gb->apu.is_active[GB_NOISE] = false;
|
|
update_sample(gb, GB_NOISE, 0, 0);
|
|
}
|
|
}
|
|
}
|
|
gb->apu.noise_channel.length_enabled = value & 0x40;
|
|
break;
|
|
}
|
|
|
|
default:
|
|
if (reg >= GB_IO_WAV_START && reg <= GB_IO_WAV_END) {
|
|
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2] = value >> 4;
|
|
gb->apu.wave_channel.wave_form[(reg - GB_IO_WAV_START) * 2 + 1] = value & 0xF;
|
|
}
|
|
}
|
|
gb->io_registers[reg] = value;
|
|
}
|
|
|
|
void GB_set_sample_rate(GB_gameboy_t *gb, unsigned sample_rate)
|
|
{
|
|
|
|
gb->apu_output.sample_rate = sample_rate;
|
|
if (sample_rate) {
|
|
gb->apu_output.highpass_rate = pow(0.999958, GB_get_clock_rate(gb) / (double)sample_rate);
|
|
}
|
|
gb->apu_output.rate_set_in_clocks = false;
|
|
GB_apu_update_cycles_per_sample(gb);
|
|
}
|
|
|
|
void GB_set_sample_rate_by_clocks(GB_gameboy_t *gb, double cycles_per_sample)
|
|
{
|
|
|
|
if (cycles_per_sample == 0) {
|
|
GB_set_sample_rate(gb, 0);
|
|
return;
|
|
}
|
|
gb->apu_output.cycles_per_sample = cycles_per_sample;
|
|
gb->apu_output.sample_rate = GB_get_clock_rate(gb) / cycles_per_sample * 2;
|
|
gb->apu_output.highpass_rate = pow(0.999958, cycles_per_sample);
|
|
gb->apu_output.rate_set_in_clocks = true;
|
|
}
|
|
|
|
void GB_apu_set_sample_callback(GB_gameboy_t *gb, GB_sample_callback_t callback)
|
|
{
|
|
gb->apu_output.sample_callback = callback;
|
|
}
|
|
|
|
void GB_set_highpass_filter_mode(GB_gameboy_t *gb, GB_highpass_mode_t mode)
|
|
{
|
|
gb->apu_output.highpass_mode = mode;
|
|
}
|
|
|
|
void GB_apu_update_cycles_per_sample(GB_gameboy_t *gb)
|
|
{
|
|
if (gb->apu_output.rate_set_in_clocks) return;
|
|
if (gb->apu_output.sample_rate) {
|
|
gb->apu_output.cycles_per_sample = 2 * GB_get_clock_rate(gb) / (double)gb->apu_output.sample_rate; /* 2 * because we use 8MHz units */
|
|
}
|
|
}
|
|
|
|
void GB_set_interference_volume(GB_gameboy_t *gb, double volume)
|
|
{
|
|
gb->apu_output.interference_volume = volume;
|
|
}
|