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comparison snes_spc/spc.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 /* SNES SPC-700 APU emulator C interface (also usable from C++) */
2
3 /* snes_spc 0.9.0 */
4 #ifndef SPC_H
5 #define SPC_H
6
7 #include <stddef.h>
8
9 #ifdef __cplusplus
10 extern "C" {
11 #endif
12
13 /* Error string return. NULL if success, otherwise error message. */
14 typedef const char* spc_err_t;
15
16 typedef struct SNES_SPC SNES_SPC;
17
18 /* Creates new SPC emulator. NULL if out of memory. */
19 SNES_SPC* spc_new( void );
20
21 /* Frees SPC emulator */
22 void spc_delete( SNES_SPC* );
23
24 /* Sample pairs generated per second */
25 enum { spc_sample_rate = 32000 };
26
27
28 /**** Emulator use ****/
29
30 /* Sets IPL ROM data. Library does not include ROM data. Most SPC music files
31 don't need ROM, but a full emulator must provide this. */
32 enum { spc_rom_size = 0x40 };
33 void spc_init_rom( SNES_SPC*, unsigned char const rom [spc_rom_size] );
34
35 /* Sets destination for output samples */
36 typedef short spc_sample_t;
37 void spc_set_output( SNES_SPC*, spc_sample_t* out, int out_size );
38
39 /* Number of samples written to output since last set */
40 int spc_sample_count( SNES_SPC const* );
41
42 /* Resets SPC to power-on state. This resets your output buffer, so you must
43 call spc_set_output() after this. */
44 void spc_reset( SNES_SPC* );
45
46 /* Emulates pressing reset switch on SNES. This resets your output buffer, so
47 you must call spc_set_output() after this. */
48 void spc_soft_reset( SNES_SPC* );
49
50 /* 1024000 SPC clocks per second, sample pair every 32 clocks */
51 typedef int spc_time_t;
52 enum { spc_clock_rate = 1024000 };
53 enum { spc_clocks_per_sample = 32 };
54
55 /* Reads/writes port at specified time */
56 enum { spc_port_count = 4 };
57 int spc_read_port ( SNES_SPC*, spc_time_t, int port );
58 void spc_write_port( SNES_SPC*, spc_time_t, int port, int data );
59
60 /* Runs SPC to end_time and starts a new time frame at 0 */
61 void spc_end_frame( SNES_SPC*, spc_time_t end_time );
62
63
64 /**** Sound control ****/
65
66 /*Mutes voices corresponding to non-zero bits in mask. Reduces emulation accuracy. */
67 enum { spc_voice_count = 8 };
68 void spc_mute_voices( SNES_SPC*, int mask );
69
70 /* If true, prevents channels and global volumes from being phase-negated.
71 Only supported by fast DSP; has no effect on accurate DSP. */
72 void spc_disable_surround( SNES_SPC*, int disable );
73
74 /* Sets tempo, where spc_tempo_unit = normal, spc_tempo_unit / 2 = half speed, etc. */
75 enum { spc_tempo_unit = 0x100 };
76 void spc_set_tempo( SNES_SPC*, int );
77
78
79 /**** SPC music playback *****/
80
81 /* Loads SPC data into emulator. Returns NULL on success, otherwise error string. */
82 spc_err_t spc_load_spc( SNES_SPC*, void const* spc_in, long size );
83
84 /* Clears echo region. Useful after loading an SPC as many have garbage in echo. */
85 void spc_clear_echo( SNES_SPC* );
86
87 /* Plays for count samples and write samples to out. Discards samples if out
88 is NULL. Count must be a multiple of 2 since output is stereo. */
89 spc_err_t spc_play( SNES_SPC*, int count, short* out );
90
91 /* Skips count samples. Several times faster than spc_play(). */
92 spc_err_t spc_skip( SNES_SPC*, int count );
93
94
95 /**** State save/load (only available with accurate DSP) ****/
96
97 /* Saves/loads exact emulator state */
98 enum { spc_state_size = 67 * 1024L }; /* maximum space needed when saving */
99 typedef void (*spc_copy_func_t)( unsigned char** io, void* state, size_t );
100 void spc_copy_state( SNES_SPC*, unsigned char** io, spc_copy_func_t );
101
102 /* Writes minimal SPC file header to spc_out */
103 void spc_init_header( void* spc_out );
104
105 /* Saves emulator state as SPC file data. Writes spc_file_size bytes to spc_out.
106 Does not set up SPC header; use spc_init_header() for that. */
107 enum { spc_file_size = 0x10200 }; /* spc_out must have this many bytes allocated */
108 void spc_save_spc( SNES_SPC*, void* spc_out );
109
110 /* Returns non-zero if new key-on events occurred since last check. Useful for
111 trimming silence while saving an SPC. */
112 int spc_check_kon( SNES_SPC* );
113
114
115 /**** SPC_Filter ****/
116
117 typedef struct SPC_Filter SPC_Filter;
118
119 /* Creates new filter. NULL if out of memory. */
120 SPC_Filter* spc_filter_new( void );
121
122 /* Frees filter */
123 void spc_filter_delete( SPC_Filter* );
124
125 /* Filters count samples of stereo sound in place. Count must be a multiple of 2. */
126 void spc_filter_run( SPC_Filter*, spc_sample_t* io, int count );
127
128 /* Clears filter to silence */
129 void spc_filter_clear( SPC_Filter* );
130
131 /* Sets gain (volume), where spc_filter_gain_unit is normal. Gains greater than
132 spc_filter_gain_unit are fine, since output is clamped to 16-bit sample range. */
133 enum { spc_filter_gain_unit = 0x100 };
134 void spc_filter_set_gain( SPC_Filter*, int gain );
135
136 /* Sets amount of bass (logarithmic scale) */
137 enum { spc_filter_bass_none = 0 };
138 enum { spc_filter_bass_norm = 8 }; /* normal amount */
139 enum { spc_filter_bass_max = 31 };
140 void spc_filter_set_bass( SPC_Filter*, int bass );
141
142
143 #ifdef __cplusplus
144 }
145 #endif
146
147 #endif