77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
#ifndef apu_h
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#define apu_h
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#include <stdbool.h>
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#include <stdint.h>
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#include "gb_struct_def.h"
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#ifdef GB_INTERNAL
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/* Divides nicely and never overflows with 4 channels */
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#define MAX_CH_AMP 0x1E00
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#define CH_STEP (MAX_CH_AMP/0xF)
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#endif
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/* Lengths are in either DIV ticks (256Hz, triggered by the DIV register) or
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APU ticks (2MHz, triggered by an internal APU clock)*/
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typedef struct
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{
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int16_t left;
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int16_t right;
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} GB_sample_t;
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typedef struct
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{
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double left;
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double right;
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} GB_double_sample_t;
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enum GB_CHANNELS {
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GB_SQUARE_1,
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GB_SQUARE_2,
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GB_WAVE,
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GB_NOISE,
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GB_N_CHANNELS
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};
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typedef struct
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{
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bool global_enable;
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uint8_t left_volume;
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uint8_t right_volume;
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uint8_t samples[GB_N_CHANNELS];
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bool left_enabled[GB_N_CHANNELS];
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bool right_enabled[GB_N_CHANNELS];
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bool is_active[GB_N_CHANNELS];
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struct {
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bool enable; // NR30
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uint8_t pulse_length; // Reloaded from NR31 (xorred), in DIV ticks
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uint8_t shift; // NR32
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uint16_t sample_length; // NR33, NR34, in APU ticks
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bool length_enabled; // NR34
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uint16_t sample_countdown; // in APU ticks
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uint8_t current_sample_index;
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uint8_t current_sample; // Current sample before shifting.
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int8_t wave_form[32];
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bool wave_form_just_read;
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} wave_channel;
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} GB_apu_t;
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void GB_set_sample_rate(GB_gameboy_t *gb, unsigned int sample_rate);
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void GB_apu_copy_buffer(GB_gameboy_t *gb, GB_sample_t *dest, unsigned int count);
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unsigned GB_apu_get_current_buffer_length(GB_gameboy_t *gb);
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#ifdef GB_INTERNAL
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void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value);
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uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg);
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void GB_apu_div_event(GB_gameboy_t *gb);
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void GB_apu_init(GB_gameboy_t *gb);
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void GB_apu_run(GB_gameboy_t *gb, uint8_t cycles);
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#endif
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#endif /* apu_h */
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