#ifndef apu_h #define apu_h #include #include #include #include "defs.h" #ifdef GB_INTERNAL /* Speed = 1 / Length (in seconds) */ #define DAC_DECAY_SPEED 20000 #define DAC_ATTACK_SPEED 20000 /* Divides nicely and never overflows with 4 channels and 8 (1-8) volume levels */ #ifdef WIIU /* Todo: Remove this hack once https://github.com/libretro/RetroArch/issues/6252 is fixed*/ #define MAX_CH_AMP (0xFF0 / 2) #else #define MAX_CH_AMP 0xFF0 #endif #define CH_STEP (MAX_CH_AMP/0xF/8) #endif /* APU ticks are 2MHz, triggered by an internal APU clock. */ typedef struct { int16_t left; int16_t right; } GB_sample_t; typedef struct { double left; double right; } GB_double_sample_t; enum GB_CHANNELS { GB_SQUARE_1, GB_SQUARE_2, GB_WAVE, GB_NOISE, GB_N_CHANNELS }; typedef struct { bool locked:1; bool clock:1; // Represents FOSY on channel 4 unsigned padding:6; } GB_envelope_clock_t; typedef void (*GB_sample_callback_t)(GB_gameboy_t *gb, GB_sample_t *sample); typedef struct { bool global_enable; uint16_t apu_cycles; uint8_t samples[GB_N_CHANNELS]; bool is_active[GB_N_CHANNELS]; uint8_t div_divider; // The DIV register ticks the APU at 512Hz, but is then divided // once more to generate 128Hz and 64Hz clocks uint8_t lf_div; // The APU runs in 2MHz, but channels 1, 2 and 4 run in 1MHZ so we divide // need to divide the signal. uint8_t square_sweep_countdown; // In 128Hz uint8_t square_sweep_calculate_countdown; // In 2 MHz uint16_t sweep_length_addend; uint16_t shadow_sweep_sample_length; bool unshifted_sweep; bool enable_zombie_calculate_stepping; uint8_t channel_1_restart_hold; uint16_t channel1_completed_addend; struct { uint16_t pulse_length; // Reloaded from NRX1 (xorred), in 256Hz DIV ticks uint8_t current_volume; // Reloaded from NRX2 uint8_t volume_countdown; // Reloaded from NRX2 uint8_t current_sample_index; bool sample_surpressed; uint16_t sample_countdown; // in APU ticks (Reloaded from sample_length, xorred $7FF) uint16_t sample_length; // From NRX3, NRX4, in APU ticks bool length_enabled; // NRX4 GB_envelope_clock_t envelope_clock; } square_channels[2]; struct { bool enable; // NR30 uint16_t pulse_length; // Reloaded from NR31 (xorred), in 256Hz DIV ticks uint8_t shift; // NR32 uint16_t sample_length; // NR33, NR34, in APU ticks bool length_enabled; // NR34 uint16_t sample_countdown; // in APU ticks (Reloaded from sample_length, xorred $7FF) uint8_t current_sample_index; uint8_t current_sample_byte; // Current sample byte. bool wave_form_just_read; bool pulsed; uint8_t bugged_read_countdown; } wave_channel; struct { uint16_t pulse_length; // Reloaded from NR41 (xorred), in 256Hz DIV ticks uint8_t current_volume; // Reloaded from NR42 uint8_t volume_countdown; // Reloaded from NR42 uint16_t lfsr; bool narrow; uint8_t counter_countdown; // Counts from 0-7 to 0 to tick counter (Scaled from 512KHz to 2MHz) uint16_t counter; // A bit from this 14-bit register ticks LFSR bool length_enabled; // NR44 uint8_t alignment; // If (NR43 & 7) != 0, samples are aligned to 512KHz clock instead of // 1MHz. This variable keeps track of the alignment. bool current_lfsr_sample; int8_t delta; bool countdown_reloaded; uint8_t dmg_delayed_start; GB_envelope_clock_t envelope_clock; } noise_channel; enum { GB_SKIP_DIV_EVENT_INACTIVE, GB_SKIP_DIV_EVENT_SKIPPED, GB_SKIP_DIV_EVENT_SKIP, } skip_div_event:8; uint8_t pcm_mask[2]; // For CGB-0 to CGB-C PCM read glitch } GB_apu_t; typedef enum { GB_HIGHPASS_OFF, // Do not apply any filter, keep DC offset GB_HIGHPASS_ACCURATE, // Apply a highpass filter similar to the one used on hardware GB_HIGHPASS_REMOVE_DC_OFFSET, // Remove DC Offset without affecting the waveform GB_HIGHPASS_MAX } GB_highpass_mode_t; typedef struct { unsigned sample_rate; unsigned sample_cycles; // Counts by sample_rate until it reaches the clock frequency // Samples are NOT normalized to MAX_CH_AMP * 4 at this stage! unsigned cycles_since_render; unsigned last_update[GB_N_CHANNELS]; GB_sample_t current_sample[GB_N_CHANNELS]; GB_sample_t summed_samples[GB_N_CHANNELS]; double dac_discharge[GB_N_CHANNELS]; GB_highpass_mode_t highpass_mode; double highpass_rate; GB_double_sample_t highpass_diff; GB_sample_callback_t sample_callback; double interference_volume; double interference_highpass; } GB_apu_output_t; void GB_set_sample_rate(GB_gameboy_t *gb, unsigned sample_rate); void GB_set_sample_rate_by_clocks(GB_gameboy_t *gb, double cycles_per_sample); /* Cycles are in 8MHz units */ void GB_set_highpass_filter_mode(GB_gameboy_t *gb, GB_highpass_mode_t mode); void GB_set_interference_volume(GB_gameboy_t *gb, double volume); void GB_apu_set_sample_callback(GB_gameboy_t *gb, GB_sample_callback_t callback); #ifdef GB_INTERNAL internal bool GB_apu_is_DAC_enabled(GB_gameboy_t *gb, unsigned index); internal void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value); internal uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg); internal void GB_apu_div_event(GB_gameboy_t *gb); internal void GB_apu_div_secondary_event(GB_gameboy_t *gb); internal void GB_apu_init(GB_gameboy_t *gb); internal void GB_apu_run(GB_gameboy_t *gb, bool force); #endif #endif /* apu_h */