audio.c 18.3 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560
#include <ultra64.h>
#include <assert.h>
#include <PR/ramrom.h>
#include <gng.h>
#include <controller.h>
#include "audio.h"
#include "../testDriver/zaru.h"

#define TEST_LEFT     0
#define TEST_RIGHT    1
#define TEST_MUSIC    2
#define TEST_MUSIC441	3
#define TEST_MUSIC320 4
#define TEST_MUSIC220 5

extern int controllerSlot;

extern OSMesgQueue   rspMessageQ,dmaMessageQ;

void AudioTest(int outRate);
void InitAudio(void);
static void romCopy(const char *src, const char *dest, const int len);
static void doSequence(int seqLen,int testNum);

static s32       __DMAAlloc(s32 addr, s32 len, void *state);
static void      __clearAudioDMA(void);
static ALDMAproc __dmaNew(DMAState **state);


DMAState    dmaState;
DMABuffer   dmaBuffs[NBUFFERS];
u32         audFrameCt;
ALSeqPlayer *seqp;
ALSeq       *seq;
u8          *seqData;
ALGlobals   audGlbs;
u32         curBuf;
u32         nextDMA;

Acmd        *cmdList[2];
OSTask      *taskPtr[2];
s16         *audioBuffer[2];

OSMesgQueue      AIMessageQ;
OSMesg           AIMessageBuf[4];

OSMesgQueue    timerMsgQ;
OSMesg         timerMsgBuf;

/** Queues and storage for use with audio DMA's ****/
OSIoMesg        audDMAIOMesgBuf[NUM_DMA_MESSAGES];
OSMesgQueue     audDMAMessageQ;
OSMesg          audDMAMessageBuf[NUM_DMA_MESSAGES];

ALHeap          aHeapRec;
u8              audioHeap[AUDIO_HEAP_SIZE];

char tstring[] = "test 00";

int audMain(void)
{
    ZaruSetSound(ZARU_SOUND_OFF);

		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDL); /* sasano added */
    AudioTest(TEST_LEFT);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDR); /* sasano added */
    AudioTest(TEST_RIGHT);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDM); /* sasano added */
    AudioTest(TEST_MUSIC);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDE); /* sasano added */
    AudioTest(TEST_MUSIC441);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDE); /* sasano added */
    AudioTest(TEST_MUSIC320);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDE); /* sasano added */
    AudioTest(TEST_MUSIC220);
		ZaruWriteReg2(REG_SOUND,ZARU_SOUNDE); /* sasano added */
    return(0);
}
int music44100(void){
      gng_report("Audio test 44100Hz\nMusic left\nMusic right\nMusic stereo", 0, 0, 0);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSIC44100); /* sasano added */
    AudioTest(TEST_MUSIC441);
		return(0);
}
int music32000(void){
      gng_report("Audio test 32000Hz\nMusic left\nMusic right\nMusic stereo", 0, 0, 0);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSIC32000); /* sasano added */
    AudioTest(TEST_MUSIC320);
		return(0);
}
int music22050(void){
      gng_report("Audio test 22050Hz\nMusic left\nMusic right\nMusic stereo", 0, 0, 0);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSIC22050); /* sasano added */
    AudioTest(TEST_MUSIC220);
		return(0);
}

static void MoveAudio(void)
{
    int    i, *ipt;
    u8     *hpStart;

    if(osMemSize > 0x400000)
    {
	hpStart = audioHeap + 0x400000;
	ipt = (int*)hpStart;
	for(i = 0; i < (AUDIO_HEAP_SIZE/4); i++)
	    ipt[i] = 0;

	alHeapInit(&aHeapRec, hpStart, AUDIO_HEAP_SIZE);    
	cmdList[0] = alHeapAlloc(&aHeapRec, 1, MAX_RSP_CMDS*sizeof(Acmd));
	cmdList[1] = alHeapAlloc(&aHeapRec, 1, MAX_RSP_CMDS*sizeof(Acmd));
	taskPtr[0] = alHeapAlloc(&aHeapRec, 1, sizeof(OSTask));
	taskPtr[1] = alHeapAlloc(&aHeapRec, 1, sizeof(OSTask));
	audioBuffer[0] = alHeapAlloc(&aHeapRec, 1, sizeof(s32)*NUM_SMPL_PER_FRAME);
	audioBuffer[1] = alHeapAlloc(&aHeapRec, 1, sizeof(s32)*NUM_SMPL_PER_FRAME);
    
	dmaBuffs[0].node.prev = 0; 
	dmaBuffs[0].node.next = 0;
	for (i=0; i<NUM_DMA_BUFFERS-1; i++)
	{
	    alLink((ALLink*)&dmaBuffs[i+1],(ALLink*)&dmaBuffs[i]);
	    dmaBuffs[i].ptr = alHeapAlloc(&aHeapRec, 1, DMA_BUFFER_LENGTH);
	}

	dmaBuffs[i].ptr = alHeapAlloc(&aHeapRec, 1, DMA_BUFFER_LENGTH);
    }
}

void InitAudio(void)
{
    ALBankFile    *bankPtr;
    u32           bankLen;
    ALSynConfig   sync;
    ALSeqpConfig  seqpc;
    u32           i,lenMax,*ipt;
    u32           len;

    osCreateMesgQueue(&AIMessageQ, AIMessageBuf, 4);
    osSetEventMesg(OS_EVENT_AI, &AIMessageQ, NULL);
    osSendMesg(&AIMessageQ,NULL,OS_MESG_BLOCK); 
    osCreateMesgQueue(&audDMAMessageQ, audDMAMessageBuf, NUM_DMA_MESSAGES);
    osCreateMesgQueue(&timerMsgQ, &timerMsgBuf, 1);
    

    ipt = (u32*)audioHeap;
    for(i = 0; i < (AUDIO_HEAP_SIZE/4); i++)
	ipt[i] = 0;

    alHeapInit(&aHeapRec, (u8 *) audioHeap, AUDIO_HEAP_SIZE);

    cmdList[0] = alHeapAlloc(&aHeapRec, 1, MAX_RSP_CMDS*sizeof(Acmd));
    cmdList[1] = alHeapAlloc(&aHeapRec, 1, MAX_RSP_CMDS*sizeof(Acmd));
    taskPtr[0] = alHeapAlloc(&aHeapRec, 1, sizeof(OSTask));
    taskPtr[1] = alHeapAlloc(&aHeapRec, 1, sizeof(OSTask));
    audioBuffer[0] = alHeapAlloc(&aHeapRec, 1, sizeof(s32)*NUM_SMPL_PER_FRAME);
    audioBuffer[1] = alHeapAlloc(&aHeapRec, 1, sizeof(s32)*NUM_SMPL_PER_FRAME);
    
    dmaState.initialized = 0;
    dmaBuffs[0].node.prev = 0; 
    dmaBuffs[0].node.next = 0;
    for (i=0; i<NUM_DMA_BUFFERS-1; i++)
    {
        alLink((ALLink*)&dmaBuffs[i+1],(ALLink*)&dmaBuffs[i]);
        dmaBuffs[i].ptr = alHeapAlloc(&aHeapRec, 1, DMA_BUFFER_LENGTH);
    }
    /* last buffer already linked, but still needs buffer */
    dmaBuffs[i].ptr = alHeapAlloc(&aHeapRec, 1, DMA_BUFFER_LENGTH);

    bankLen = _bankSegmentRomEnd - _bankSegmentRomStart;
    bankPtr = alHeapAlloc(&aHeapRec, 1, bankLen);
    romCopy(_bankSegmentRomStart, (char *)bankPtr, bankLen);
    alBnkfNew(bankPtr, (u8 *) _tableSegmentRomStart);

    sync.maxVVoices = MAX_VOICES;
    sync.maxPVoices = MAX_VOICES;
    sync.maxUpdates = MAX_UPDATES;
    sync.dmaproc    = __dmaNew; 
    sync.fxType	    = 0;
    sync.outputRate = 22050;      /* each test better reset this value */
    sync.heap       = &aHeapRec;

    alInit(&audGlbs,&sync);
        
    seqpc.maxVoices      = MAX_VOICES;
    seqpc.maxEvents      = MAX_EVENTS;
    seqpc.maxChannels    = 16;
#ifdef NOT_IN_20C
    /*
     * debugFlags and these corresponding defintions are only present in
     * releases after 2.0.C.  Since we don't use them anywhere else, 
     * it's safe to comment them out here.
     */
    seqpc.debugFlags     = NO_VOICE_ERR_MASK |NOTE_OFF_ERR_MASK | NO_SOUND_ERR_MASK;
#endif
    seqpc.heap           = &aHeapRec;
    seqpc.initOsc        = 0;
    seqpc.updateOsc      = 0;
    seqpc.stopOsc        = 0;

    seqp = alHeapAlloc(&aHeapRec, 1, sizeof(ALSeqPlayer));
    alSeqpNew(seqp, &seqpc);
    alSeqpSetBank(seqp, bankPtr->bankArray[0]); 
    seq = alHeapAlloc(&aHeapRec, 1, sizeof(ALSeq));

    len = _seq1SegmentRomEnd - _seq1SegmentRomStart;
    lenMax = _seq2SegmentRomEnd - _seq2SegmentRomStart;
    lenMax = MAX(len,lenMax);
    len = _seq3SegmentRomEnd - _seq3SegmentRomStart;
    lenMax = MAX(len,lenMax);
    len = _subwaySegmentRomEnd - _subwaySegmentRomStart;
    lenMax = MAX(len,lenMax);
    seqData = alHeapAlloc(&aHeapRec, 1, lenMax);
}

void playSubway(void)
{
    u32  seqLen;

	if (ZaruReadReg(REG_PLAYSUBWAY)!=0){
    audGlbs.drvr.outputRate = osAiSetFrequency(44100);  
    seqLen = _subwaySegmentRomEnd - _subwaySegmentRomStart;
    romCopy(_subwaySegmentRomStart, (char *) seqData, seqLen);
    doSequence(seqLen,2);
	}
}

void AudioTest(int testNum)
{
    u32      seqLen;
    OSTimer  timer;
    u32      c;

    switch (testNum)
    {
	case TEST_LEFT:
	    gng_report("Audio test LEFT\nListen for two tones.", 0, 0, 0);
	    audGlbs.drvr.outputRate = osAiSetFrequency(44100);  
	    /* copy the "tune" sequence into memory */
	    seqLen = _seq1SegmentRomEnd - _seq1SegmentRomStart;
	    romCopy(_seq1SegmentRomStart, (char *) seqData, seqLen);
	    /* turn on zaru and play the "tune" sequence */
	    ZaruSetSound(ZARU_SOUND_L);
	    osSetTimer(&timer,OS_USEC_TO_CYCLES((u64)400000),0,&timerMsgQ,NULL);
	    osRecvMesg(&timerMsgQ, NULL, OS_MESG_BLOCK);
	    doSequence(seqLen,2);
	    ZaruSetSound(ZARU_SOUND_OFF);
	    gng_report("Test complete, push button.", 0, 0, 0);
	    break;
	case TEST_RIGHT:
	    ZaruWaitForNextTestButton();
	    gng_report("Audio test RIGHT\nListen for two tones.", 0, 0, 0);
	    audGlbs.drvr.outputRate = osAiSetFrequency(44100); 
	    /* copy the "tune" sequence into memory */
	    seqLen = _seq2SegmentRomEnd - _seq2SegmentRomStart;
	    romCopy(_seq2SegmentRomStart, (char *) seqData, seqLen);
	    /* turn on zaru and play the "tune" sequence */
	    ZaruSetSound(ZARU_SOUND_R);
	    osSetTimer(&timer,OS_USEC_TO_CYCLES((u64)400000),0,&timerMsgQ,NULL);
	    osRecvMesg(&timerMsgQ, NULL, OS_MESG_BLOCK);
	    doSequence(seqLen,2);
	    ZaruSetSound(ZARU_SOUND_OFF);
	    gng_report("Test complete, push button.", 0, 0, 0);
	    break;
	case TEST_MUSIC441:
      audGlbs.drvr.outputRate = osAiSetFrequency(44100);
      seqLen = _seq3SegmentRomEnd - _seq3SegmentRomStart;
      romCopy(_seq3SegmentRomStart, (char *) seqData, seqLen);
      MoveAudio();
      doSequence(seqLen,2);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSICEND); /* sasano added */
			break;
  case TEST_MUSIC320:
      audGlbs.drvr.outputRate = osAiSetFrequency(32000);
      seqLen = _seq3SegmentRomEnd - _seq3SegmentRomStart;
      romCopy(_seq3SegmentRomStart, (char *) seqData, seqLen);
      MoveAudio();
      doSequence(seqLen,1);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSICEND); /* sasano added */
			break;
  case TEST_MUSIC220:
      audGlbs.drvr.outputRate = osAiSetFrequency(22050);
      seqLen = _seq3SegmentRomEnd - _seq3SegmentRomStart;
      romCopy(_seq3SegmentRomStart, (char *) seqData, seqLen);
      MoveAudio();
      doSequence(seqLen,0);
      ZaruWriteReg2(REG_MUSIC,ZARU_MUSICEND); /* sasano added */
			break;
  default:
			break;
    }


#ifdef OLD_WAY    
    /* copy the "tune" sequence into memory */
    seqLen = _seq1SegmentRomEnd - _seq1SegmentRomStart;
    romCopy(_seq1SegmentRomStart, (char *) seqData, seqLen);
    /* play the "tune" sequence */
    doSequence(seqLen,testNum);

    /* copy the "sweep" sequence into memory */
    seqLen = _seq2SegmentRomEnd - _seq2SegmentRomStart;
    romCopy(_seq2SegmentRomStart, (char *) seqData, seqLen);
    /* turn on the zaru then wait .2 secs */
    ZaruSetSound(ZARU_SOUND_LR); 
    osSetTimer(&timer,OS_USEC_TO_CYCLES((u64)200000),0,&timerMsgQ,NULL);
    osRecvMesg(&timerMsgQ, NULL, OS_MESG_BLOCK);
    /* start the "sweep" sequence */
    doSequence(seqLen,testNum+3);
    ZaruSetSound(ZARU_SOUND_OFF);
#endif
}

static void doSequence(int seqLen,int testNum)
{
    s16      *audioOp;
    Acmd     *cmdLp;
    s32      clcount;
    OSTask   *task;
    u32      i;

    alSeqNew(seq, seqData, seqLen);
    alSeqpSetSeq(seqp, seq);
    alSeqpPlay(seqp);

    alSeqpSetChlProgram(seqp,0,(u8)testNum);
    alSeqpSetChlProgram(seqp,1,(u8)testNum);
    alSeqpSetChlProgram(seqp,2,(u8)testNum);
    alSeqpSetVol(seqp,0x7fff);

    do {

	__clearAudioDMA();
	audioOp = (s16*) osVirtualToPhysical(audioBuffer[curBuf]);
	cmdLp = alAudioFrame(cmdList[curBuf], &clcount, audioOp, NUM_SMPL_PER_FRAME);

	
	if(clcount)
	{
	    task = taskPtr[curBuf]; 
	    task->t.dram_stack = 0;
	    task->t.output_buff = 0;
	    task->t.output_buff_size = 0;
            task->t.type = M_AUDTASK;
            task->t.flags = 0x0;
            task->t.ucode_boot = (u64 *) rspbootTextStart;
            task->t.ucode_boot_size = ((s32)rspbootTextEnd -
                                         (s32)rspbootTextStart);
            task->t.ucode = (u64 *) aspMainTextStart;
            task->t.ucode_data = (u64 *) aspMainDataStart;
            task->t.ucode_size = 4096;
            task->t.ucode_data_size = sizeof(u64)*(aspMainDataEnd - aspMainDataStart); 
            task->t.data_ptr = (u64 *) cmdList[curBuf];
            task->t.data_size = (cmdLp - cmdList[curBuf]) * sizeof(Acmd);
            
            /* Empty the dma queue to make sure all DMAs have completed.   */
            for (i=0; i<nextDMA; i++)
		osRecvMesg(&audDMAMessageQ, NULL, OS_MESG_NOBLOCK);


            osWritebackDCacheAll();
            osSpTaskStart(task);

	    osRecvMesg(&rspMessageQ, NULL, OS_MESG_BLOCK);

	    osAiSetNextBuffer(audioBuffer[curBuf], NUM_SMPL_PER_FRAME * 4);
	    osRecvMesg(&AIMessageQ, NULL, OS_MESG_BLOCK);
	}
	
	curBuf ^= 1;

    } while (seqp->state != AL_STOPPED);

}



static void romCopy(const char *src, const char *dest, const int len)
{
    OSIoMesg dmaIoMesgBuf;
    OSMesg dummyMesg;
    
    /*
     * Always invalidate cache before dma'ing data into the buffer.
     * This is to prevent a flush of the cache in the future from 
     * potentially trashing some data that has just been dma'ed in.
     * Since you don't care if old data makes it from cache out to 
     * memory, you can use the cheaper osInvalDCache() instead of one
     * of the writeback commands
     */
    osInvalDCache((void *)dest, (s32) len);
    osPiStartDma(&dmaIoMesgBuf, OS_MESG_PRI_NORMAL, OS_READ,
                 (u32)src, (void *)dest, (u32)len, &dmaMessageQ);
    (void) osRecvMesg(&dmaMessageQ, &dummyMesg, OS_MESG_BLOCK);
}

/******************************************************************************
 *
 * __amDMA This routine handles the dma'ing of samples from rom to ram.
 * First it checks the current buffers to see if the samples needed are
 * already in place. Because buffers are linked sequentially by the
 * addresses where the samples are on rom, it doesn't need to check all
 * of them, only up to the address that it needs. If it finds one, it
 * returns the address of that buffer. If it doesn't find the samples 
 * that it needs, it will initiate a DMA of the samples that it needs.
 * In either case, it updates the lastFrame variable, to indicate that
 * this buffer was last used in this frame. This is important for the
 * __clearAudioDMA routine.
 *
 *****************************************************************************/
static s32 __DMAAlloc(s32 addr, s32 len, void *state)
{
    void            *foundBuffer;
    s32             delta, addrEnd, buffEnd;
    DMABuffer     *dmaPtr, *lastDmaPtr;
    
    lastDmaPtr = 0;
    dmaPtr = dmaState.firstUsed;
    addrEnd = addr+len;

    /* first check to see if a currently existing buffer contains the
       sample that you need.  */
    
    while(dmaPtr)
    {
        buffEnd = dmaPtr->startAddr + DMA_BUFFER_LENGTH;
        if(dmaPtr->startAddr > addr) /* since buffers are ordered */
            break;                   /* abort if past possible */

        else if(addrEnd <= buffEnd) /* yes, found a buffer with samples */
        {
            dmaPtr->lastFrame = audFrameCt; /* mark it used */
            foundBuffer = dmaPtr->ptr + addr - dmaPtr->startAddr;
            return (int) osVirtualToPhysical(foundBuffer);
        }
        lastDmaPtr = dmaPtr;
        dmaPtr = (DMABuffer*)dmaPtr->node.next;
    }

    /* get here, and you didn't find a buffer, so dma a new one */

    /* get a buffer from the free list */
    dmaPtr = dmaState.firstFree;

    assert(dmaPtr);  /* be sure you have a buffer, */
                    /* if you don't have one, this is a major problem */

    dmaState.firstFree = (DMABuffer*)dmaPtr->node.next;
    alUnlink((ALLink*)dmaPtr);

    /* add it to the used list */
    if(lastDmaPtr) /* if you have other dmabuffers used, add this one */
    {              /* to the list, after the last one checked above */
        alLink((ALLink*)dmaPtr,(ALLink*)lastDmaPtr);
    }
    else if(dmaState.firstUsed) /* if this buffer is before any others */
    {                           /* jam at begining of list */ 
        lastDmaPtr = dmaState.firstUsed;
        dmaState.firstUsed = dmaPtr;
        dmaPtr->node.next = (ALLink*)lastDmaPtr;
        dmaPtr->node.prev = 0;
        lastDmaPtr->node.prev = (ALLink*)dmaPtr;
    }
    else /* no buffers in list, this is the first one */
    {
        dmaState.firstUsed = dmaPtr;
        dmaPtr->node.next = 0;
        dmaPtr->node.prev = 0;
    }
    
    foundBuffer = dmaPtr->ptr;
    delta = addr & 0x1;
    addr -= delta;
    dmaPtr->startAddr = addr;
    dmaPtr->lastFrame = audFrameCt;  /* mark it */
    osPiStartDma(&audDMAIOMesgBuf[nextDMA++], OS_MESG_PRI_NORMAL, OS_READ,
                 (u32)addr, foundBuffer, DMA_BUFFER_LENGTH, &audDMAMessageQ);

    return (int) osVirtualToPhysical(foundBuffer) + delta;
}

/******************************************************************************
 *
 * __amDmaNew.  Initialize the dma buffers and return the address of the
 * procedure that will be used to dma the samples from rom to ram. This 
 * routine will be called once for each physical voice that is created. 
 * In this case, because we know where all the buffers are, and since 
 * they are not attached to a specific voice, we will only really do any
 * initialization the first time. After that we just return the address
 * to the dma routine.
 *
 *****************************************************************************/
static ALDMAproc __dmaNew(DMAState **state)
{
    int         i;
    
    if(!dmaState.initialized)  /* only do this once */
    {
        dmaState.firstUsed = 0;
        dmaState.firstFree = &dmaBuffs[0];
        dmaState.initialized = 1;
    }

    *state = &dmaState;  /* state is never used in this case */

    return __DMAAlloc;
}

/******************************************************************************
 *
 * __clearAudioDMA.  Routine to move dma buffers back to the unused list.
 * First clear out your dma messageQ. Then check each buffer to see when
 * it was last used. If that was more than FRAME_LAG frames ago, move it
 * back to the unused list. 
 *
 *****************************************************************************/
static void __clearAudioDMA(void)
{
    u32          i;
    DMABuffer  *dmaPtr,*nextPtr;
    
    /*
     * Don't block here. If dma's aren't complete, you've had an audio
     * overrun. (Bad news, but go for it anyway, and try and recover.
     */
/*    for (i=0; i<nextDMA; i++)
        osRecvMesg(&audDMAMessageQ,NULL,OS_MESG_NOBLOCK);*/

    nextDMA = 0;  /* reset */
    
    dmaPtr = dmaState.firstUsed;
    while(dmaPtr)
    {
        nextPtr = (DMABuffer*)dmaPtr->node.next;

        /* remove old dma's from list */
        /* Can change FRAME_LAG value.  Should be at least one.  */
        /* Larger values mean more buffers needed, but fewer DMA's */
        if(dmaPtr->lastFrame + FRAME_LAG  < audFrameCt) 
        {
            if(dmaState.firstUsed == dmaPtr)
                dmaState.firstUsed = (DMABuffer*)dmaPtr->node.next;
            alUnlink((ALLink*)dmaPtr);
            if(dmaState.firstFree)
                alLink((ALLink*)dmaPtr,(ALLink*)dmaState.firstFree);
            else
            {
                dmaState.firstFree = dmaPtr;
                dmaPtr->node.next = 0;
                dmaPtr->node.prev = 0;
            }
        }
        dmaPtr = nextPtr;
    }
    

    audFrameCt++;
}