f40bfc9267
Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius <nils@rockbox.org> Tested-by: Nils Wallménius <nils@rockbox.org>
63 lines
1.7 KiB
C
63 lines
1.7 KiB
C
// Sega Master System SN76489 PSG sound chip emulator
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// Sms_Snd_Emu 0.1.2
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#ifndef SMS_APU_H
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#define SMS_APU_H
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#include "blargg_common.h"
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#include "blip_buffer.h"
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// 0: Square 1, 1: Square 2, 2: Square 3, 3: Noise
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enum { sms_osc_count = 4 }; // 0 <= chan < osc_count
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struct Osc
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{
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struct Blip_Buffer* outputs [4]; // NULL, right, left, center
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struct Blip_Buffer* output;
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int last_amp;
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int volume;
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int period;
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int delay;
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unsigned phase;
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};
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struct Sms_Apu {
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struct Osc oscs [sms_osc_count];
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int ggstereo;
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int latch;
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blip_time_t last_time;
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int min_tone_period;
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unsigned noise_feedback;
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unsigned looped_feedback;
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struct Blip_Synth synth;
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};
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// Basics
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void Sms_apu_init( struct Sms_Apu* this );
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// Sets buffer(s) to generate sound into, or 0 to mute. If only center is not 0,
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// output is mono.
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void Sms_apu_set_output( struct Sms_Apu* this, int i, struct Blip_Buffer* center, struct Blip_Buffer* left, struct Blip_Buffer* right);
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// Emulates to time t, then writes data to Game Gear left/right assignment byte
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void Sms_apu_write_ggstereo( struct Sms_Apu* this, blip_time_t t, int data );
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// Emulates to time t, then writes data
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void Sms_apu_write_data( struct Sms_Apu* this, blip_time_t t, int data );
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// Emulates to time t, then subtracts t from the current time.
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// OK if previous write call had time slightly after t.
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void Sms_apu_end_frame( struct Sms_Apu* this, blip_time_t t );
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// More features
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// Resets sound chip and sets noise feedback bits and width
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void Sms_apu_reset( struct Sms_Apu* this, unsigned noise_feedback, int noise_width );
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// Sets overall volume, where 1.0 is normal
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void Sms_apu_volume( struct Sms_Apu* this, int vol );
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#endif
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