diff options
Diffstat (limited to 'opl/opl_sdl.c')
| -rw-r--r-- | opl/opl_sdl.c | 158 |
1 files changed, 108 insertions, 50 deletions
diff --git a/opl/opl_sdl.c b/opl/opl_sdl.c index 1963d5cd..f6a3b229 100644 --- a/opl/opl_sdl.c +++ b/opl/opl_sdl.c @@ -33,7 +33,7 @@ #include "SDL.h" #include "SDL_mixer.h" -#include "fmopl.h" +#include "dbopl.h" #include "opl.h" #include "opl_internal.h" @@ -42,6 +42,14 @@ #define MAX_SOUND_SLICE_TIME 100 /* ms */ +typedef struct +{ + unsigned int rate; // Number of times the timer is advanced per sec. + unsigned int enabled; // Non-zero if timer is enabled. + unsigned int value; // Last value that was set. + unsigned int expire_time; // Calculated time that timer will expire. +} opl_timer_t; + // When the callback mutex is locked using OPL_Lock, callback functions // are not invoked. @@ -70,11 +78,20 @@ static unsigned int pause_offset; // OPL software emulator structure. -static FM_OPL *opl_emulator = NULL; +static Chip opl_chip; // Temporary mixing buffer used by the mixing callback. -static int16_t *mix_buffer = NULL; +static int32_t *mix_buffer = NULL; + +// Register number that was written. + +static int register_num = 0; + +// Timers; DBOPL does not do timer stuff itself. + +static opl_timer_t timer1 = { 12500, 0, 0, 0 }; +static opl_timer_t timer2 = { 3125, 0, 0, 0 }; // SDL parameters. @@ -153,14 +170,14 @@ static void FillBuffer(int16_t *buffer, unsigned int nsamples) assert(nsamples < mixing_freq); - YM3812UpdateOne(opl_emulator, mix_buffer, nsamples, 0); + Chip__GenerateBlock2(&opl_chip, nsamples, mix_buffer); // Mix into the destination buffer, doubling up into stereo. for (i=0; i<nsamples; ++i) { - buffer[i * 2] = mix_buffer[i]; - buffer[i * 2 + 1] = mix_buffer[i]; + buffer[i * 2] = (int16_t) (mix_buffer[i] * 2); + buffer[i * 2 + 1] = (int16_t) (mix_buffer[i] * 2); } } @@ -179,7 +196,7 @@ static void OPL_Mix_Callback(void *udata, buffer = (int16_t *) byte_buffer; buffer_len = buffer_bytes / 4; - // Repeatedly call the FMOPL update function until the buffer is + // Repeatedly call the OPL emulator update function until the buffer is // full. while (filled < buffer_len) @@ -235,11 +252,13 @@ static void OPL_SDL_Shutdown(void) sdl_was_initialized = 0; } - if (opl_emulator != NULL) +/* + if (opl_chip != NULL) { - OPLDestroy(opl_emulator); - opl_emulator = NULL; + OPLDestroy(opl_chip); + opl_chip = NULL; } + */ if (callback_mutex != NULL) { @@ -254,29 +273,6 @@ static void OPL_SDL_Shutdown(void) } } -// Callback when a timer expires. - -static void TimerOver(void *data) -{ - int channel = (int) data; - - OPLTimerOver(opl_emulator, channel); -} - -// Callback invoked when the emulator code wants to set a timer. - -static void TimerHandler(int channel, double interval_seconds) -{ - unsigned int interval_samples; - - interval_samples = (int) (interval_seconds * mixing_freq); - - SDL_LockMutex(callback_queue_mutex); - OPL_Queue_Push(callback_queue, TimerOver, (void *) channel, - current_time - pause_offset + interval_samples); - SDL_UnlockMutex(callback_queue_mutex); -} - static unsigned int GetSliceSize(void) { int limit; @@ -360,20 +356,13 @@ static int OPL_SDL_Init(unsigned int port_base) // Mix buffer: - mix_buffer = malloc(mixing_freq * 2); + mix_buffer = malloc(mixing_freq * sizeof(uint32_t)); // Create the emulator structure: - opl_emulator = makeAdlibOPL(mixing_freq); - - if (opl_emulator == NULL) - { - fprintf(stderr, "Failed to initialize software OPL emulator!\n"); - OPL_SDL_Shutdown(); - return 0; - } - - OPLSetTimerHandler(opl_emulator, TimerHandler, 0); + DBOPL_InitTables(); + Chip__Chip(&opl_chip); + Chip__Setup(&opl_chip, mixing_freq); callback_mutex = SDL_CreateMutex(); callback_queue_mutex = SDL_CreateMutex(); @@ -386,21 +375,90 @@ static int OPL_SDL_Init(unsigned int port_base) static unsigned int OPL_SDL_PortRead(opl_port_t port) { - if (opl_emulator != NULL) + unsigned int result = 0; + + if (timer1.enabled && current_time > timer1.expire_time) { - return OPLRead(opl_emulator, port); + result |= 0x80; // Either have expired + result |= 0x40; // Timer 1 has expired } - else + + if (timer2.enabled && current_time > timer2.expire_time) { - return 0; + result |= 0x80; // Either have expired + result |= 0x20; // Timer 2 has expired + } + + return result; +} + +static void OPLTimer_CalculateEndTime(opl_timer_t *timer) +{ + int tics; + + // If the timer is enabled, calculate the time when the timer + // will expire. + + if (timer->enabled) + { + tics = 0x100 - timer->value; + timer->expire_time = current_time + + (tics * opl_sample_rate) / timer->rate; + } +} + +static void WriteRegister(unsigned int reg_num, unsigned int value) +{ + switch (reg_num) + { + case OPL_REG_TIMER1: + timer1.value = value; + OPLTimer_CalculateEndTime(&timer1); + break; + + case OPL_REG_TIMER2: + timer2.value = value; + OPLTimer_CalculateEndTime(&timer2); + break; + + case OPL_REG_TIMER_CTRL: + if (value & 0x80) + { + timer1.enabled = 0; + timer2.enabled = 0; + } + else + { + if ((value & 0x40) == 0) + { + timer1.enabled = (value & 0x01) != 0; + OPLTimer_CalculateEndTime(&timer1); + } + + if ((value & 0x20) == 0) + { + timer1.enabled = (value & 0x02) != 0; + OPLTimer_CalculateEndTime(&timer2); + } + } + + break; + + default: + Chip__WriteReg(&opl_chip, reg_num, value); + break; } } static void OPL_SDL_PortWrite(opl_port_t port, unsigned int value) { - if (opl_emulator != NULL) + if (port == OPL_REGISTER_PORT) + { + register_num = value; + } + else if (port == OPL_DATA_PORT) { - OPLWrite(opl_emulator, port, value); + WriteRegister(register_num, value); } } |