1// Highly accurate SNES SPC-700 DSP emulator
2
3// snes_spc 0.9.0
4#ifndef SPC_DSP_H
5#define SPC_DSP_H
6
7#include "blargg_common.h"
8
9extern "C" { typedef void (*dsp_copy_func_t)( unsigned char** io, void* state, size_t ); }
10
11class SPC_DSP {
12public:
13 typedef BOOST::uint8_t uint8_t;
14
15// Setup
16
17 // Initializes DSP and has it use the 64K RAM provided
18 void init( void* ram_64k );
19
20 // Sets destination for output samples. If out is NULL or out_size is 0,
21 // doesn't generate any.
22 typedef short sample_t;
23 void set_output( sample_t* out, int out_size );
24
25 void set_output( Resampler* resampler );
26
27 // Number of samples written to output since it was last set, always
28 // a multiple of 2. Undefined if more samples were generated than
29 // output buffer could hold.
30 int sample_count() const;
31
32// Emulation
33
34 // Resets DSP to power-on state
35 void reset();
36
37 // Emulates pressing reset switch on SNES
38 void soft_reset();
39
40 // Reads/writes DSP registers. For accuracy, you must first call run()
41 // to catch the DSP up to present.
42 int read ( int addr ) const;
43 void write( int addr, int data );
44
45 // Runs DSP for specified number of clocks (~1024000 per second). Every 32 clocks
46 // a pair of samples is be generated.
47 void run( int clock_count );
48
49// Sound control
50
51 // Mutes voices corresponding to non-zero bits in mask (issues repeated KOFF events).
52 // Reduces emulation accuracy.
53 enum { voice_count = 8 };
54 void mute_voices( int mask );
55
56// State
57
58 // Resets DSP and uses supplied values to initialize registers
59 enum { register_count = 128 };
60 void load( uint8_t const regs [register_count] );
61
62 // Saves/loads exact emulator state
63 enum { state_size = 640 }; // maximum space needed when saving
64 typedef dsp_copy_func_t copy_func_t;
65 void copy_state( unsigned char** io, copy_func_t );
66
67 // Returns non-zero if new key-on events occurred since last call
68 bool check_kon();
69
70// Snes9x Accessor
71
72 int stereo_switch;
73 int take_spc_snapshot;
74 void (*spc_snapshot_callback) (void);
75
76 void set_spc_snapshot_callback( void (*callback) (void) );
77 void dump_spc_snapshot( void );
78 void set_stereo_switch( int );
79 uint8_t reg_value( int, int );
80 int envx_value( int );
81
82// DSP register addresses
83
84 // Global registers
85 enum {
86 r_mvoll = 0x0C, r_mvolr = 0x1C,
87 r_evoll = 0x2C, r_evolr = 0x3C,
88 r_kon = 0x4C, r_koff = 0x5C,
89 r_flg = 0x6C, r_endx = 0x7C,
90 r_efb = 0x0D, r_pmon = 0x2D,
91 r_non = 0x3D, r_eon = 0x4D,
92 r_dir = 0x5D, r_esa = 0x6D,
93 r_edl = 0x7D,
94 r_fir = 0x0F // 8 coefficients at 0x0F, 0x1F ... 0x7F
95 };
96
97 // Voice registers
98 enum {
99 v_voll = 0x00, v_volr = 0x01,
100 v_pitchl = 0x02, v_pitchh = 0x03,
101 v_srcn = 0x04, v_adsr0 = 0x05,
102 v_adsr1 = 0x06, v_gain = 0x07,
103 v_envx = 0x08, v_outx = 0x09
104 };
105
106public:
107 enum { extra_size = 16 };
108 sample_t* extra() { return m.extra; }
109 sample_t const* out_pos() const { return m.out; }
110 void disable_surround( bool ) { } // not supported
111public:
112 BLARGG_DISABLE_NOTHROW
113
114 typedef BOOST::int8_t int8_t;
115 typedef BOOST::int16_t int16_t;
116
117 enum { echo_hist_size = 8 };
118
119 enum env_mode_t { env_release, env_attack, env_decay, env_sustain };
120 enum { brr_buf_size = 12 };
121 struct voice_t
122 {
123 int buf [brr_buf_size*2];// decoded samples (twice the size to simplify wrap handling)
124 int buf_pos; // place in buffer where next samples will be decoded
125 int interp_pos; // relative fractional position in sample (0x1000 = 1.0)
126 int brr_addr; // address of current BRR block
127 int brr_offset; // current decoding offset in BRR block
128 uint8_t* regs; // pointer to voice's DSP registers
129 int vbit; // bitmask for voice: 0x01 for voice 0, 0x02 for voice 1, etc.
130 int kon_delay; // KON delay/current setup phase
131 env_mode_t env_mode;
132 int env; // current envelope level
133 int hidden_env; // used by GAIN mode 7, very obscure quirk
134 uint8_t t_envx_out;
135 int voice_number;
136 };
137private:
138 enum { brr_block_size = 9 };
139
140 Resampler *resampler;
141
142 struct state_t
143 {
144 uint8_t regs [register_count];
145
146 // Echo history keeps most recent 8 samples (twice the size to simplify wrap handling)
147 int echo_hist [echo_hist_size * 2] [2];
148 int (*echo_hist_pos) [2]; // &echo_hist [0 to 7]
149
150 int every_other_sample; // toggles every sample
151 int kon; // KON value when last checked
152 int noise;
153 int counter;
154 int echo_offset; // offset from ESA in echo buffer
155 int echo_length; // number of bytes that echo_offset will stop at
156 int phase; // next clock cycle to run (0-31)
157 bool kon_check; // set when a new KON occurs
158
159 // Hidden registers also written to when main register is written to
160 int new_kon;
161 uint8_t endx_buf;
162 uint8_t envx_buf;
163 uint8_t outx_buf;
164
165 // Temporary state between clocks
166
167 // read once per sample
168 int t_pmon;
169 int t_non;
170 int t_eon;
171 int t_dir;
172 int t_koff;
173
174 // read a few clocks ahead then used
175 int t_brr_next_addr;
176 int t_adsr0;
177 int t_brr_header;
178 int t_brr_byte;
179 int t_srcn;
180 int t_esa;
181 int t_echo_enabled;
182
183 // internal state that is recalculated every sample
184 int t_dir_addr;
185 int t_pitch;
186 int t_output;
187 int t_looped;
188 int t_echo_ptr;
189
190 // left/right sums
191 int t_main_out [2];
192 int t_echo_out [2];
193 int t_echo_in [2];
194
195 voice_t voices [voice_count];
196
197 // non-emulation state
198 uint8_t* ram; // 64K shared RAM between DSP and SMP
199 int mute_mask;
200
201 sample_t* out;
202 sample_t* out_end;
203 sample_t* out_begin;
204 sample_t extra [extra_size];
205
206 uint8_t separate_echo_buffer [0x10000];
207 };
208 state_t m;
209
210 void init_counter();
211 void run_counters();
212 unsigned read_counter( int rate );
213
214 int interpolate( voice_t const* v );
215 void run_envelope( voice_t* const v );
216 void decode_brr( voice_t* v );
217
218 void misc_27();
219 void misc_28();
220 void misc_29();
221 void misc_30();
222
223 void voice_output( voice_t const* v, int ch );
224 void voice_V1( voice_t* const );
225 void voice_V2( voice_t* const );
226 void voice_V3( voice_t* const );
227 void voice_V3a( voice_t* const );
228 void voice_V3b( voice_t* const );
229 void voice_V3c( voice_t* const );
230 void voice_V4( voice_t* const );
231 void voice_V5( voice_t* const );
232 void voice_V6( voice_t* const );
233 void voice_V7( voice_t* const );
234 void voice_V8( voice_t* const );
235 void voice_V9( voice_t* const );
236 void voice_V7_V4_V1( voice_t* const );
237 void voice_V8_V5_V2( voice_t* const );
238 void voice_V9_V6_V3( voice_t* const );
239
240 void echo_read( int ch );
241 int echo_output( int ch );
242 void echo_write( int ch );
243 void echo_22();
244 void echo_23();
245 void echo_24();
246 void echo_25();
247 void echo_26();
248 void echo_27();
249 void echo_28();
250 void echo_29();
251 void echo_30();
252
253 void soft_reset_common();
254};
255
256#include <assert.h>
257
258inline int SPC_DSP::sample_count() const { return m.out - m.out_begin; }
259
260inline int SPC_DSP::read( int addr ) const
261{
262 assert( (unsigned) addr < register_count );
263 return m.regs [addr];
264}
265
266inline void SPC_DSP::write( int addr, int data )
267{
268 assert( (unsigned) addr < register_count );
269
270 m.regs [addr] = (uint8_t) data;
271 switch ( addr & 0x0F )
272 {
273 case v_envx:
274 m.envx_buf = (uint8_t) data;
275 break;
276
277 case v_outx:
278 m.outx_buf = (uint8_t) data;
279 break;
280
281 case 0x0C:
282 if ( addr == r_kon )
283 m.new_kon = (uint8_t) data;
284
285 if ( addr == r_endx ) // always cleared, regardless of data written
286 {
287 m.endx_buf = 0;
288 m.regs [r_endx] = 0;
289 }
290 break;
291 }
292}
293
294inline void SPC_DSP::mute_voices( int mask ) { m.mute_mask = mask; }
295
296inline bool SPC_DSP::check_kon()
297{
298 bool old = m.kon_check;
299 m.kon_check = 0;
300 return old;
301}
302
303#if !SPC_NO_COPY_STATE_FUNCS
304
305class SPC_State_Copier {
306 SPC_DSP::copy_func_t func;
307 unsigned char** buf;
308public:
309 SPC_State_Copier( unsigned char** p, SPC_DSP::copy_func_t f ) { func = f; buf = p; }
310 void copy( void* state, size_t size );
311 int copy_int( int state, int size );
312 void skip( int count );
313 void extra();
314};
315
316#define SPC_COPY( type, state )\
317{\
318 state = (BOOST::type) copier.copy_int( state, sizeof (BOOST::type) );\
319 assert( (BOOST::type) state == state );\
320}
321
322#endif
323
324#endif
325