13cbade08a
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30397 a1c6a512-1295-4272-9138-f99709370657
89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
// Turbo Grafx 16 (PC Engine) ADPCM sound chip emulator
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// Game_Music_Emu 0.6-pre
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#ifndef HES_APU_ADPCM_H
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#define HES_APU_ADPCM_H
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#include "blargg_source.h"
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#include "blargg_common.h"
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#include "blip_buffer.h"
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enum { adpcm_amp_range = 2048 };
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enum { adpcm_osc_count = 1 }; // 0 <= chan < osc_count
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// Registers are at io_addr to io_addr+io_size-1
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enum { adpcm_io_addr = 0x1800 };
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enum { adpcm_io_size = 0x400 };
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struct State
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{
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byte pcmbuf [0x10000];
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byte port [0x10];
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int ad_sample;
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int ad_ref_index;
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bool ad_low_nibble;
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int freq;
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unsigned short addr;
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unsigned short writeptr;
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unsigned short readptr;
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unsigned short playptr;
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byte playflag;
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byte repeatflag;
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int length;
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int playlength;
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int playedsamplecount;
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int volume;
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int fadetimer;
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int fadecount;
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};
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struct Hes_Apu_Adpcm {
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struct State state;
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struct Blip_Synth synth;
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struct Blip_Buffer* output;
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blip_time_t last_time;
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int next_timer;
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int last_amp;
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};
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// Init HES adpcm sound chip
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void Adpcm_init( struct Hes_Apu_Adpcm* this );
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// Rest HES adpcm sound chip
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void Adpcm_reset( struct Hes_Apu_Adpcm* 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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static inline void Adpcm_set_output( struct Hes_Apu_Adpcm* this, int chan, struct Blip_Buffer* center, struct Blip_Buffer* left, struct Blip_Buffer* right )
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{
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// Must be silent (all NULL), mono (left and right NULL), or stereo (none NULL)
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require( !center || (center && !left && !right) || (center && left && right) );
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require( (unsigned) chan < adpcm_osc_count ); // fails if you pass invalid osc index
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#if defined(ROCKBOX)
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(void) chan;
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#endif
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if ( !center || !left || !right )
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{
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left = center;
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right = center;
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}
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this->output = center;
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}
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// Emulates to time t, then writes data to addr
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void Adpcm_write_data( struct Hes_Apu_Adpcm* this, blip_time_t t, int addr, int data );
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// Emulates to time t, then reads from addr
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int Adpcm_read_data( struct Hes_Apu_Adpcm* this, blip_time_t t, int addr );
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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 Adpcm_end_frame( struct Hes_Apu_Adpcm* this,blip_time_t t );
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// Sets overall volume, where 1.0 is normal
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static inline void Adpcm_volume( struct Hes_Apu_Adpcm* this, int v ) { Synth_volume( &this->synth, (v*3)/5 / adpcm_osc_count / adpcm_amp_range ); }
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#endif
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