1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
// AY-3-8910 sound chip ulator
// Game_Music_Emu 0.6-pre
#ifndef AY_APU_H
#define AY_APU_H
#include "blargg_common.h"
#include "blargg_source.h"
#include "blip_buffer.h"
// Number of registers
enum { ay_reg_count = 16 };
enum { ay_osc_count = 3 };
enum { ay_amp_range = 255 };
struct osc_t
{
blip_time_t period;
blip_time_t delay;
short last_amp;
short phase;
struct Blip_Buffer* output;
};
struct Ay_Apu {
struct osc_t oscs [ay_osc_count];
blip_time_t last_time;
byte addr_;
byte regs [ay_reg_count];
blip_time_t noise_delay;
unsigned noise_lfsr;
blip_time_t env_delay;
byte const* env_wave;
int env_pos;
byte env_modes [8] [48]; // values already passed through volume table
struct Blip_Synth synth_; // used by Ay_Core for beeper sound
};
void Ay_apu_init( struct Ay_Apu* this );
// Writes to address register
static inline void Ay_apu_write_addr( struct Ay_Apu* this, int data ) { this->addr_ = data & 0x0F; }
// Emulates to time t, then writes to current data register
void run_until( struct Ay_Apu* this, blip_time_t final_end_time );;
void write_data_( struct Ay_Apu* this, int addr, int data );
static inline void Ay_apu_write_data( struct Ay_Apu* this, blip_time_t t, int data ) { run_until( this, t ); write_data_( this, this->addr_, data ); }
// Reads from current data register
int Ay_apu_read( struct Ay_Apu* this );
// Resets sound chip
void Ay_apu_reset( struct Ay_Apu* this );
// Sets overall volume, where 1.0 is normal
static inline void Ay_apu_volume( struct Ay_Apu* this, int v ) { Synth_volume( &this->synth_, (v*7)/10 /ay_osc_count/ay_amp_range ); }
static inline void Ay_apu_set_output( struct Ay_Apu* this, int i, struct Blip_Buffer* out )
{
assert( (unsigned) i < ay_osc_count );
this->oscs [i].output = out;
}
// Emulates to time t, then subtracts t from the current time.
// OK if previous write call had time slightly after t.
static inline void Ay_apu_end_frame( struct Ay_Apu* this, blip_time_t time )
{
if ( time > this->last_time )
run_until( this, time );
this->last_time -= time;
assert( this->last_time >= 0 );
}
#endif
|
