| 1 | // |
| 2 | // DAC (really, Synchronous Serial Interface) Handler |
| 3 | // |
| 4 | // Originally by David Raingeard |
| 5 | // GCC/SDL port by Niels Wagenaar (Linux/WIN32) and Caz (BeOS) |
| 6 | // Rewritten by James Hammons |
| 7 | // (C) 2010 Underground Software |
| 8 | // |
| 9 | // JLH = James Hammons <jlhamm@acm.org> |
| 10 | // |
| 11 | // Who When What |
| 12 | // --- ---------- ------------------------------------------------------------- |
| 13 | // JLH 01/16/2010 Created this log ;-) |
| 14 | // JLH 04/30/2012 Changed SDL audio handler to run JERRY |
| 15 | // |
| 16 | |
| 17 | // Need to set up defaults that the BIOS sets for the SSI here in DACInit()... !!! FIX !!! |
| 18 | // or something like that... Seems like it already does, but it doesn't seem to |
| 19 | // work correctly...! Perhaps just need to set up SSI stuff so BUTCH doesn't get |
| 20 | // confused... |
| 21 | |
| 22 | // After testing on a real Jaguar, it seems clear that the I2S interrupt drives |
| 23 | // the audio subsystem. So while you can drive the audio at a *slower* rate than |
| 24 | // set by SCLK, you can't drive it any *faster*. Also note, that if the I2S |
| 25 | // interrupt is not enabled/running on the DSP, then there is no audio. Also, |
| 26 | // audio can be muted by clearing bit 8 of JOYSTICK (JOY1). |
| 27 | // |
| 28 | // Approach: We can run the DSP in the host system's audio IRQ, by running the |
| 29 | // DSP for the alloted time (depending on the host buffer size & sample rate) |
| 30 | // by simply reading the L/R_I2S (L/RTXD) registers at regular intervals. We |
| 31 | // would also have to time the I2S/TIMER0/TIMER1 interrupts in the DSP as well. |
| 32 | // This way, we can run the host audio IRQ at, say, 48 KHz and not have to care |
| 33 | // so much about SCLK and running a separate buffer and all the attendant |
| 34 | // garbage that comes with that awful approach. |
| 35 | // |
| 36 | // There would still be potential gotchas, as the SCLK can theoretically drive |
| 37 | // the I2S at 26590906 / 2 (for SCLK == 0) = 13.3 MHz which corresponds to an |
| 38 | // audio rate 416 KHz (dividing the I2S rate by 32, for 16-bit stereo). It |
| 39 | // seems doubtful that anything useful could come of such a high rate, and we |
| 40 | // can probably safely ignore any such ridiculously high audio rates. It won't |
| 41 | // sound the same as on a real Jaguar, but who cares? :-) |
| 42 | |
| 43 | #include "dac.h" |
| 44 | |
| 45 | #include "SDL.h" |
| 46 | #include "cdrom.h" |
| 47 | #include "dsp.h" |
| 48 | #include "event.h" |
| 49 | #include "jerry.h" |
| 50 | #include "jaguar.h" |
| 51 | #include "log.h" |
| 52 | #include "m68000/m68kinterface.h" |
| 53 | //#include "memory.h" |
| 54 | #include "settings.h" |
| 55 | |
| 56 | |
| 57 | //#define DEBUG_DAC |
| 58 | |
| 59 | #define BUFFER_SIZE 0x10000 // Make the DAC buffers 64K x 16 bits |
| 60 | #define DAC_AUDIO_RATE 48000 // Set the audio rate to 48 KHz |
| 61 | |
| 62 | // Jaguar memory locations |
| 63 | |
| 64 | #define LTXD 0xF1A148 |
| 65 | #define RTXD 0xF1A14C |
| 66 | #define LRXD 0xF1A148 |
| 67 | #define RRXD 0xF1A14C |
| 68 | #define SCLK 0xF1A150 |
| 69 | #define SMODE 0xF1A154 |
| 70 | |
| 71 | // Global variables |
| 72 | |
| 73 | // These are defined in memory.h/cpp |
| 74 | //uint16_t lrxd, rrxd; // I2S ports (into Jaguar) |
| 75 | |
| 76 | // Local variables |
| 77 | |
| 78 | static SDL_AudioSpec desired; |
| 79 | static bool SDLSoundInitialized; |
| 80 | //static uint8_t SCLKFrequencyDivider = 19; // Default is roughly 22 KHz (20774 Hz in NTSC mode) |
| 81 | // /*static*/ uint16_t serialMode = 0; |
| 82 | |
| 83 | // Private function prototypes |
| 84 | |
| 85 | void SDLSoundCallback(void * userdata, Uint8 * buffer, int length); |
| 86 | void DSPSampleCallback(void); |
| 87 | |
| 88 | |
| 89 | // |
| 90 | // Initialize the SDL sound system |
| 91 | // |
| 92 | void DACInit(void) |
| 93 | { |
| 94 | SDLSoundInitialized = false; |
| 95 | |
| 96 | // if (!vjs.audioEnabled) |
| 97 | if (!vjs.DSPEnabled) |
| 98 | { |
| 99 | WriteLog("DAC: DSP/host audio playback disabled.\n"); |
| 100 | return; |
| 101 | } |
| 102 | |
| 103 | desired.freq = DAC_AUDIO_RATE; |
| 104 | desired.format = AUDIO_S16SYS; |
| 105 | desired.channels = 2; |
| 106 | desired.samples = 2048; // 2K buffer = audio delay of 42.67 ms (@ 48 KHz) |
| 107 | desired.callback = SDLSoundCallback; |
| 108 | |
| 109 | if (SDL_OpenAudio(&desired, NULL) < 0) // NULL means SDL guarantees what we want |
| 110 | WriteLog("DAC: Failed to initialize SDL sound...\n"); |
| 111 | else |
| 112 | { |
| 113 | SDLSoundInitialized = true; |
| 114 | DACReset(); |
| 115 | SDL_PauseAudio(false); // Start playback! |
| 116 | WriteLog("DAC: Successfully initialized. Sample rate: %u\n", desired.freq); |
| 117 | } |
| 118 | |
| 119 | ltxd = lrxd = desired.silence; |
| 120 | sclk = 19; // Default is roughly 22 KHz |
| 121 | |
| 122 | uint32_t riscClockRate = (vjs.hardwareTypeNTSC ? RISC_CLOCK_RATE_NTSC : RISC_CLOCK_RATE_PAL); |
| 123 | uint32_t cyclesPerSample = riscClockRate / DAC_AUDIO_RATE; |
| 124 | WriteLog("DAC: RISC clock = %u, cyclesPerSample = %u\n", riscClockRate, cyclesPerSample); |
| 125 | } |
| 126 | |
| 127 | |
| 128 | // |
| 129 | // Reset the sound buffer FIFOs |
| 130 | // |
| 131 | void DACReset(void) |
| 132 | { |
| 133 | // LeftFIFOHeadPtr = LeftFIFOTailPtr = 0, RightFIFOHeadPtr = RightFIFOTailPtr = 1; |
| 134 | ltxd = lrxd = desired.silence; |
| 135 | } |
| 136 | |
| 137 | |
| 138 | // |
| 139 | // Pause/unpause the SDL audio thread |
| 140 | // |
| 141 | void DACPauseAudioThread(bool state/*= true*/) |
| 142 | { |
| 143 | SDL_PauseAudio(state); |
| 144 | } |
| 145 | |
| 146 | |
| 147 | // |
| 148 | // Close down the SDL sound subsystem |
| 149 | // |
| 150 | void DACDone(void) |
| 151 | { |
| 152 | if (SDLSoundInitialized) |
| 153 | { |
| 154 | SDL_PauseAudio(true); |
| 155 | SDL_CloseAudio(); |
| 156 | } |
| 157 | |
| 158 | WriteLog("DAC: Done.\n"); |
| 159 | } |
| 160 | |
| 161 | |
| 162 | // Approach: Run the DSP for however many cycles needed to correspond to whatever sample rate |
| 163 | // we've set the audio to run at. So, e.g., if we run it at 48 KHz, then we would run the DSP |
| 164 | // for however much time it takes to fill the buffer. So with a 2K buffer, this would correspond |
| 165 | // to running the DSP for 0.042666... seconds. At 26590906 Hz, this would correspond to |
| 166 | // running the DSP for 1134545 cycles. You would then sample the L/RTXD registers every |
| 167 | // 1134545 / 2048 = 554 cycles to fill the buffer. You would also have to manage interrupt |
| 168 | // timing as well (generating them at the proper times), but that shouldn't be too difficult... |
| 169 | // If the DSP isn't running, then fill the buffer with L/RTXD and exit. |
| 170 | |
| 171 | // |
| 172 | // SDL callback routine to fill audio buffer |
| 173 | // |
| 174 | // Note: The samples are packed in the buffer in 16 bit left/16 bit right pairs. |
| 175 | // Also, length is the length of the buffer in BYTES |
| 176 | // |
| 177 | static Uint8 * sampleBuffer; |
| 178 | static int bufferIndex = 0; |
| 179 | static int numberOfSamples = 0; |
| 180 | static bool bufferDone = false; |
| 181 | void SDLSoundCallback(void * userdata, Uint8 * buffer, int length) |
| 182 | { |
| 183 | // 1st, check to see if the DSP is running. If not, fill the buffer with L/RXTD and exit. |
| 184 | |
| 185 | if (!DSPIsRunning()) |
| 186 | { |
| 187 | for(int i=0; i<(length/2); i+=2) |
| 188 | { |
| 189 | ((uint16_t *)buffer)[i + 0] = ltxd; |
| 190 | ((uint16_t *)buffer)[i + 1] = rtxd; |
| 191 | } |
| 192 | |
| 193 | return; |
| 194 | } |
| 195 | |
| 196 | // The length of time we're dealing with here is 1/48000 s, so we multiply this |
| 197 | // by the number of cycles per second to get the number of cycles for one sample. |
| 198 | // uint32_t riscClockRate = (vjs.hardwareTypeNTSC ? RISC_CLOCK_RATE_NTSC : RISC_CLOCK_RATE_PAL); |
| 199 | // uint32_t cyclesPerSample = riscClockRate / DAC_AUDIO_RATE; |
| 200 | // This is the length of time |
| 201 | // timePerSample = (1000000.0 / (double)riscClockRate) * (); |
| 202 | |
| 203 | // Now, run the DSP for that length of time for each sample we need to make |
| 204 | |
| 205 | bufferIndex = 0; |
| 206 | sampleBuffer = buffer; |
| 207 | // If length is the length of the sample buffer in BYTES, then shouldn't the # of |
| 208 | // samples be / 4? No, because we bump the sample count by 2, so this is OK. |
| 209 | numberOfSamples = length / 2; |
| 210 | bufferDone = false; |
| 211 | |
| 212 | SetCallbackTime(DSPSampleCallback, 1000000.0 / (double)DAC_AUDIO_RATE, EVENT_JERRY); |
| 213 | |
| 214 | // These timings are tied to NTSC, need to fix that in event.cpp/h! [FIXED] |
| 215 | do |
| 216 | { |
| 217 | double timeToNextEvent = GetTimeToNextEvent(EVENT_JERRY); |
| 218 | |
| 219 | if (vjs.DSPEnabled) |
| 220 | { |
| 221 | if (vjs.usePipelinedDSP) |
| 222 | DSPExecP2(USEC_TO_RISC_CYCLES(timeToNextEvent)); |
| 223 | else |
| 224 | DSPExec(USEC_TO_RISC_CYCLES(timeToNextEvent)); |
| 225 | } |
| 226 | |
| 227 | HandleNextEvent(EVENT_JERRY); |
| 228 | } |
| 229 | while (!bufferDone); |
| 230 | } |
| 231 | |
| 232 | |
| 233 | void DSPSampleCallback(void) |
| 234 | { |
| 235 | ((uint16_t *)sampleBuffer)[bufferIndex + 0] = ltxd; |
| 236 | ((uint16_t *)sampleBuffer)[bufferIndex + 1] = rtxd; |
| 237 | bufferIndex += 2; |
| 238 | |
| 239 | if (bufferIndex == numberOfSamples) |
| 240 | { |
| 241 | bufferDone = true; |
| 242 | return; |
| 243 | } |
| 244 | |
| 245 | SetCallbackTime(DSPSampleCallback, 1000000.0 / (double)DAC_AUDIO_RATE, EVENT_JERRY); |
| 246 | } |
| 247 | |
| 248 | |
| 249 | #if 0 |
| 250 | // |
| 251 | // Calculate the frequency of SCLK * 32 using the divider |
| 252 | // |
| 253 | int GetCalculatedFrequency(void) |
| 254 | { |
| 255 | int systemClockFrequency = (vjs.hardwareTypeNTSC ? RISC_CLOCK_RATE_NTSC : RISC_CLOCK_RATE_PAL); |
| 256 | |
| 257 | // We divide by 32 here in order to find the frequency of 32 SCLKs in a row (transferring |
| 258 | // 16 bits of left data + 16 bits of right data = 32 bits, 1 SCLK = 1 bit transferred). |
| 259 | return systemClockFrequency / (32 * (2 * (SCLKFrequencyDivider + 1))); |
| 260 | } |
| 261 | #endif |
| 262 | |
| 263 | |
| 264 | // |
| 265 | // LTXD/RTXD/SCLK/SMODE ($F1A148/4C/50/54) |
| 266 | // |
| 267 | void DACWriteByte(uint32_t offset, uint8_t data, uint32_t who/*= UNKNOWN*/) |
| 268 | { |
| 269 | WriteLog("DAC: %s writing BYTE %02X at %08X\n", whoName[who], data, offset); |
| 270 | if (offset == SCLK + 3) |
| 271 | DACWriteWord(offset - 3, (uint16_t)data); |
| 272 | } |
| 273 | |
| 274 | |
| 275 | void DACWriteWord(uint32_t offset, uint16_t data, uint32_t who/*= UNKNOWN*/) |
| 276 | { |
| 277 | if (offset == LTXD + 2) |
| 278 | { |
| 279 | ltxd = data; |
| 280 | } |
| 281 | else if (offset == RTXD + 2) |
| 282 | { |
| 283 | rtxd = data; |
| 284 | } |
| 285 | else if (offset == SCLK + 2) // Sample rate |
| 286 | { |
| 287 | WriteLog("DAC: Writing %u to SCLK (by %s)...\n", data, whoName[who]); |
| 288 | |
| 289 | sclk = data & 0xFF; |
| 290 | JERRYI2SInterruptTimer = -1; |
| 291 | RemoveCallback(JERRYI2SCallback); |
| 292 | JERRYI2SCallback(); |
| 293 | } |
| 294 | else if (offset == SMODE + 2) |
| 295 | { |
| 296 | // serialMode = data; |
| 297 | smode = data; |
| 298 | WriteLog("DAC: %s writing to SMODE. Bits: %s%s%s%s%s%s [68K PC=%08X]\n", whoName[who], |
| 299 | (data & 0x01 ? "INTERNAL " : ""), (data & 0x02 ? "MODE " : ""), |
| 300 | (data & 0x04 ? "WSEN " : ""), (data & 0x08 ? "RISING " : ""), |
| 301 | (data & 0x10 ? "FALLING " : ""), (data & 0x20 ? "EVERYWORD" : ""), |
| 302 | m68k_get_reg(NULL, M68K_REG_PC)); |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | |
| 307 | // |
| 308 | // LRXD/RRXD/SSTAT ($F1A148/4C/50) |
| 309 | // |
| 310 | uint8_t DACReadByte(uint32_t offset, uint32_t who/*= UNKNOWN*/) |
| 311 | { |
| 312 | // WriteLog("DAC: %s reading byte from %08X\n", whoName[who], offset); |
| 313 | return 0xFF; |
| 314 | } |
| 315 | |
| 316 | |
| 317 | //static uint16_t fakeWord = 0; |
| 318 | uint16_t DACReadWord(uint32_t offset, uint32_t who/*= UNKNOWN*/) |
| 319 | { |
| 320 | // WriteLog("DAC: %s reading word from %08X\n", whoName[who], offset); |
| 321 | // return 0xFFFF; |
| 322 | // WriteLog("DAC: %s reading WORD %04X from %08X\n", whoName[who], fakeWord, offset); |
| 323 | // return fakeWord++; |
| 324 | //NOTE: This only works if a bunch of things are set in BUTCH which we currently don't |
| 325 | // check for. !!! FIX !!! |
| 326 | // Partially fixed: We check for I2SCNTRL in the JERRY I2S routine... |
| 327 | // return GetWordFromButchSSI(offset, who); |
| 328 | if (offset == LRXD || offset == RRXD) |
| 329 | return 0x0000; |
| 330 | else if (offset == LRXD + 2) |
| 331 | return lrxd; |
| 332 | else if (offset == RRXD + 2) |
| 333 | return rrxd; |
| 334 | |
| 335 | return 0xFFFF; // May need SSTAT as well... (but may be a Jaguar II only feature) |
| 336 | } |
| 337 | |