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comparison snes_spc/SPC_DSP.h @ 0:e38dacceb958

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initial import
author Robert McIntyre <rlm@mit.edu>
date Fri, 21 Oct 2011 05:53:11 -0700
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-1:000000000000 0:e38dacceb958
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
9 extern "C" { typedef void (*dsp_copy_func_t)( unsigned char** io, void* state, size_t ); }
10
11 class SPC_DSP {
12 public:
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 // Number of samples written to output since it was last set, always
26 // a multiple of 2. Undefined if more samples were generated than
27 // output buffer could hold.
28 int sample_count() const;
29
30 // Emulation
31
32 // Resets DSP to power-on state
33 void reset();
34
35 // Emulates pressing reset switch on SNES
36 void soft_reset();
37
38 // Reads/writes DSP registers. For accuracy, you must first call run()
39 // to catch the DSP up to present.
40 int read ( int addr ) const;
41 void write( int addr, int data );
42
43 // Runs DSP for specified number of clocks (~1024000 per second). Every 32 clocks
44 // a pair of samples is be generated.
45 void run( int clock_count );
46
47 // Sound control
48
49 // Mutes voices corresponding to non-zero bits in mask (issues repeated KOFF events).
50 // Reduces emulation accuracy.
51 enum { voice_count = 8 };
52 void mute_voices( int mask );
53
54 // State
55
56 // Resets DSP and uses supplied values to initialize registers
57 enum { register_count = 128 };
58 void load( uint8_t const regs [register_count] );
59
60 // Saves/loads exact emulator state
61 enum { state_size = 640 }; // maximum space needed when saving
62 typedef dsp_copy_func_t copy_func_t;
63 void copy_state( unsigned char** io, copy_func_t );
64
65 // Returns non-zero if new key-on events occurred since last call
66 bool check_kon();
67
68 // DSP register addresses
69
70 // Global registers
71 enum {
72 r_mvoll = 0x0C, r_mvolr = 0x1C,
73 r_evoll = 0x2C, r_evolr = 0x3C,
74 r_kon = 0x4C, r_koff = 0x5C,
75 r_flg = 0x6C, r_endx = 0x7C,
76 r_efb = 0x0D, r_pmon = 0x2D,
77 r_non = 0x3D, r_eon = 0x4D,
78 r_dir = 0x5D, r_esa = 0x6D,
79 r_edl = 0x7D,
80 r_fir = 0x0F // 8 coefficients at 0x0F, 0x1F ... 0x7F
81 };
82
83 // Voice registers
84 enum {
85 v_voll = 0x00, v_volr = 0x01,
86 v_pitchl = 0x02, v_pitchh = 0x03,
87 v_srcn = 0x04, v_adsr0 = 0x05,
88 v_adsr1 = 0x06, v_gain = 0x07,
89 v_envx = 0x08, v_outx = 0x09
90 };
91
92 public:
93 enum { extra_size = 16 };
94 sample_t* extra() { return m.extra; }
95 sample_t const* out_pos() const { return m.out; }
96 void disable_surround( bool ) { } // not supported
97 public:
98 BLARGG_DISABLE_NOTHROW
99
100 typedef BOOST::int8_t int8_t;
101 typedef BOOST::int16_t int16_t;
102
103 enum { echo_hist_size = 8 };
104
105 enum env_mode_t { env_release, env_attack, env_decay, env_sustain };
106 enum { brr_buf_size = 12 };
107 struct voice_t
108 {
109 int buf [brr_buf_size*2];// decoded samples (twice the size to simplify wrap handling)
110 int buf_pos; // place in buffer where next samples will be decoded
111 int interp_pos; // relative fractional position in sample (0x1000 = 1.0)
112 int brr_addr; // address of current BRR block
113 int brr_offset; // current decoding offset in BRR block
114 uint8_t* regs; // pointer to voice's DSP registers
115 int vbit; // bitmask for voice: 0x01 for voice 0, 0x02 for voice 1, etc.
116 int kon_delay; // KON delay/current setup phase
117 env_mode_t env_mode;
118 int env; // current envelope level
119 int hidden_env; // used by GAIN mode 7, very obscure quirk
120 uint8_t t_envx_out;
121 };
122 private:
123 enum { brr_block_size = 9 };
124
125 struct state_t
126 {
127 uint8_t regs [register_count];
128
129 // Echo history keeps most recent 8 samples (twice the size to simplify wrap handling)
130 int echo_hist [echo_hist_size * 2] [2];
131 int (*echo_hist_pos) [2]; // &echo_hist [0 to 7]
132
133 int every_other_sample; // toggles every sample
134 int kon; // KON value when last checked
135 int noise;
136 int counter;
137 int echo_offset; // offset from ESA in echo buffer
138 int echo_length; // number of bytes that echo_offset will stop at
139 int phase; // next clock cycle to run (0-31)
140 bool kon_check; // set when a new KON occurs
141
142 // Hidden registers also written to when main register is written to
143 int new_kon;
144 uint8_t endx_buf;
145 uint8_t envx_buf;
146 uint8_t outx_buf;
147
148 // Temporary state between clocks
149
150 // read once per sample
151 int t_pmon;
152 int t_non;
153 int t_eon;
154 int t_dir;
155 int t_koff;
156
157 // read a few clocks ahead then used
158 int t_brr_next_addr;
159 int t_adsr0;
160 int t_brr_header;
161 int t_brr_byte;
162 int t_srcn;
163 int t_esa;
164 int t_echo_enabled;
165
166 // internal state that is recalculated every sample
167 int t_dir_addr;
168 int t_pitch;
169 int t_output;
170 int t_looped;
171 int t_echo_ptr;
172
173 // left/right sums
174 int t_main_out [2];
175 int t_echo_out [2];
176 int t_echo_in [2];
177
178 voice_t voices [voice_count];
179
180 // non-emulation state
181 uint8_t* ram; // 64K shared RAM between DSP and SMP
182 int mute_mask;
183 sample_t* out;
184 sample_t* out_end;
185 sample_t* out_begin;
186 sample_t extra [extra_size];
187 };
188 state_t m;
189
190 void init_counter();
191 void run_counters();
192 unsigned read_counter( int rate );
193
194 int interpolate( voice_t const* v );
195 void run_envelope( voice_t* const v );
196 void decode_brr( voice_t* v );
197
198 void misc_27();
199 void misc_28();
200 void misc_29();
201 void misc_30();
202
203 void voice_output( voice_t const* v, int ch );
204 void voice_V1( voice_t* const );
205 void voice_V2( voice_t* const );
206 void voice_V3( voice_t* const );
207 void voice_V3a( voice_t* const );
208 void voice_V3b( voice_t* const );
209 void voice_V3c( voice_t* const );
210 void voice_V4( voice_t* const );
211 void voice_V5( voice_t* const );
212 void voice_V6( voice_t* const );
213 void voice_V7( voice_t* const );
214 void voice_V8( voice_t* const );
215 void voice_V9( voice_t* const );
216 void voice_V7_V4_V1( voice_t* const );
217 void voice_V8_V5_V2( voice_t* const );
218 void voice_V9_V6_V3( voice_t* const );
219
220 void echo_read( int ch );
221 int echo_output( int ch );
222 void echo_write( int ch );
223 void echo_22();
224 void echo_23();
225 void echo_24();
226 void echo_25();
227 void echo_26();
228 void echo_27();
229 void echo_28();
230 void echo_29();
231 void echo_30();
232
233 void soft_reset_common();
234 };
235
236 #include <assert.h>
237
238 inline int SPC_DSP::sample_count() const { return m.out - m.out_begin; }
239
240 inline int SPC_DSP::read( int addr ) const
241 {
242 assert( (unsigned) addr < register_count );
243 return m.regs [addr];
244 }
245
246 inline void SPC_DSP::write( int addr, int data )
247 {
248 assert( (unsigned) addr < register_count );
249
250 m.regs [addr] = (uint8_t) data;
251 switch ( addr & 0x0F )
252 {
253 case v_envx:
254 m.envx_buf = (uint8_t) data;
255 break;
256
257 case v_outx:
258 m.outx_buf = (uint8_t) data;
259 break;
260
261 case 0x0C:
262 if ( addr == r_kon )
263 m.new_kon = (uint8_t) data;
264
265 if ( addr == r_endx ) // always cleared, regardless of data written
266 {
267 m.endx_buf = 0;
268 m.regs [r_endx] = 0;
269 }
270 break;
271 }
272 }
273
274 inline void SPC_DSP::mute_voices( int mask ) { m.mute_mask = mask; }
275
276 inline bool SPC_DSP::check_kon()
277 {
278 bool old = m.kon_check;
279 m.kon_check = 0;
280 return old;
281 }
282
283 #if !SPC_NO_COPY_STATE_FUNCS
284
285 class SPC_State_Copier {
286 SPC_DSP::copy_func_t func;
287 unsigned char** buf;
288 public:
289 SPC_State_Copier( unsigned char** p, SPC_DSP::copy_func_t f ) { func = f; buf = p; }
290 void copy( void* state, size_t size );
291 int copy_int( int state, int size );
292 void skip( int count );
293 void extra();
294 };
295
296 #define SPC_COPY( type, state )\
297 {\
298 state = (BOOST::type) copier.copy_int( state, sizeof (BOOST::type) );\
299 assert( (BOOST::type) state == state );\
300 }
301
302 #endif
303
304 #endif