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// Nintendo Game Boy GBS music file emulator
// Game_Music_Emu 0.5.2
#ifndef GBS_EMU_H
#define GBS_EMU_H
#include "rom_data.h"
#include "multi_buffer.h"
#include "gb_apu.h"
#include "gb_cpu.h"
#include "m3u_playlist.h"
/* typedef uint8_t byte; */
typedef short sample_t;
enum { joypad_addr = 0xFF00 };
enum { ram_addr = 0xA000 };
enum { hi_page = 0xFF00 - ram_addr };
enum { io_base = 0xFF00 };
enum { buf_size = 2048 };
// Selects which sound hardware to use. AGB hardware is cleaner than the
// others. Doesn't take effect until next start_track().
enum sound_t {
sound_dmg = mode_dmg, // Game Boy monochrome
sound_cgb = mode_cgb, // Game Boy Color
sound_agb = mode_agb, // Game Boy Advance
sound_gbs // Use DMG/CGB based on GBS (default)
};
// GBS file header
enum { header_size = 112 };
struct header_t
{
char tag [3];
byte vers;
byte track_count;
byte first_track;
byte load_addr [2];
byte init_addr [2];
byte play_addr [2];
byte stack_ptr [2];
byte timer_modulo;
byte timer_mode;
char game [32];
char author [32];
char copyright [32];
};
struct Gbs_Emu {
enum sound_t sound_hardware;
int tempo;
// timer
blip_time_t cpu_time;
blip_time_t end_time;
blip_time_t play_period;
blip_time_t next_play;
// Sound
long clock_rate_;
long sample_rate_;
unsigned buf_changed_count;
int voice_count_;
int gain_;
int tempo_;
// track-specific
byte track_count;
volatile bool track_ended;
int current_track_;
blargg_long out_time; // number of samples played since start of track
blargg_long emu_time; // number of samples emulator has generated since start of track
bool emu_track_ended_; // emulator has reached end of track
// fading
blargg_long fade_start;
int fade_step;
// silence detection
// Disable automatic end-of-track detection and skipping of silence at beginning
bool ignore_silence;
int max_initial_silence;
int mute_mask_;
int silence_lookahead; // speed to run emulator when looking ahead for silence
long silence_time; // number of samples where most recent silence began
long silence_count; // number of samples of silence to play before using buf
long buf_remain; // number of samples left in silence buffer
// Larger items at the end
// Header for currently loaded file
struct header_t header;
// M3u Playlist
struct M3u_Playlist m3u;
struct Gb_Apu apu;
struct Gb_Cpu cpu;
struct Stereo_Buffer stereo_buf;
sample_t buf [buf_size];
// rom & ram
struct Rom_Data rom;
byte ram [0x4000 + 0x2000 + cpu_padding];
};
// Basic functionality
// Initializes Gbs_Emu structure
void Gbs_init( struct Gbs_Emu* this );
// Stops (clear) Gbs_Emu structure
void Gbs_stop( struct Gbs_Emu* this );
// Loads a file from memory
blargg_err_t Gbs_load( struct Gbs_Emu* this, void* data, long size );
// Set output sample rate. Must be called only once before loading file.
blargg_err_t Gbs_set_sample_rate( struct Gbs_Emu* this, long sample_rate );
// Start a track, where 0 is the first track. Also clears warning string.
blargg_err_t Gbs_start_track( struct Gbs_Emu* this, int );
// Generate 'count' samples info 'buf'. Output is in stereo. Any emulation
// errors set warning string, and major errors also end track.
blargg_err_t Gbs_play( struct Gbs_Emu* this, long count, sample_t* buf );
// Track status/control
// Number of milliseconds (1000 msec = 1 second) played since beginning of track
long Track_tell( struct Gbs_Emu* this );
// Seek to new time in track. Seeking backwards or far forward can take a while.
blargg_err_t Track_seek( struct Gbs_Emu* this, long msec );
// Skip n samples
blargg_err_t Track_skip( struct Gbs_Emu* this, long n );
// Set start time and length of track fade out. Once fade ends track_ended() returns
// true. Fade time can be changed while track is playing.
void Track_set_fade( struct Gbs_Emu* this, long start_msec, long length_msec );
// Get track length in milliseconds
static inline long Track_get_length( struct Gbs_Emu* this, int n )
{
long length = 120 * 1000; /* 2 minutes */
if ( (this->m3u.size > 0) && (n < this->m3u.size) ) {
struct entry_t* entry = &this->m3u.entries [n];
length = entry->length;
}
return length;
}
// Sound customization
// Adjust song tempo, where 1.0 = normal, 0.5 = half speed, 2.0 = double speed.
// Track length as returned by track_info() assumes a tempo of 1.0.
void Sound_set_tempo( struct Gbs_Emu* this, int );
// Mute/unmute voice i, where voice 0 is first voice
void Sound_mute_voice( struct Gbs_Emu* this, int index, bool mute );
// Set muting state of all voices at once using a bit mask, where -1 mutes them all,
// 0 unmutes them all, 0x01 mutes just the first voice, etc.
void Sound_mute_voices( struct Gbs_Emu* this, int mask );
// Change overall output amplitude, where 1.0 results in minimal clamping.
// Must be called before set_sample_rate().
static inline void Sound_set_gain( struct Gbs_Emu* this, int g )
{
assert( !this->sample_rate_ ); // you must set gain before setting sample rate
this->gain_ = g;
}
// Emulation (You shouldn't touch these)
blargg_err_t Run_clocks( struct Gbs_Emu* this, blip_time_t duration );
void Set_bank( struct Gbs_Emu* this, int );
void Update_timer( struct Gbs_Emu* this );
// Runs CPU until time becomes >= 0
void Run_cpu( struct Gbs_Emu* this );
// Reads/writes memory and I/O
int Read_mem( struct Gbs_Emu* this, addr_t addr );
void Write_mem( struct Gbs_Emu* this, addr_t addr, int data );
// Current time
static inline blip_time_t Time( struct Gbs_Emu* this )
{
return Cpu_time( &this->cpu ) + this->end_time;
}
void Jsr_then_stop( struct Gbs_Emu* this, byte const [] );
void Write_io_inline( struct Gbs_Emu* this, int offset, int data, int base );
void Write_io_( struct Gbs_Emu* this, int offset, int data );
int Read_io( struct Gbs_Emu* this, int offset );
void Write_io( struct Gbs_Emu* this, int offset, int data );
#endif
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