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rebuilt SDL speaker driver

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This commit is contained in:
Jorj Bauer 2019-02-20 17:49:51 -05:00
parent a93b14bc9c
commit e15db839e3
4 changed files with 149 additions and 152 deletions
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4
physicalspeaker.h
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@ -7,11 +7,15 @@ class PhysicalSpeaker {
public:
virtual ~PhysicalSpeaker() {}
virtual void begin() = 0;
virtual void toggle(uint32_t c) = 0;
virtual void maintainSpeaker(uint32_t c, uint64_t microseconds) = 0;
virtual void beginMixing() = 0;
virtual void mixOutput(uint8_t v) = 0;
virtual uint32_t bufferedContentSize() = 0;
};
#endif

57
sdl/aiie.cpp
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@ -27,7 +27,7 @@
BIOS bios;
Debugger debugger;
static struct timespec nextInstructionTime, startTime;
struct timespec nextInstructionTime, startTime;
#define NB_ENABLE 1
#define NB_DISABLE 0
@ -91,8 +91,6 @@ void write(void *arg, uint16_t address, uint8_t v)
static void *cpu_thread(void *dummyptr) {
struct timespec currentTime;
struct timespec nextSpeakerCycleTime;
uint32_t nextSpeakerCycle = 0;
#if 0
int policy;
@ -109,10 +107,9 @@ static void *cpu_thread(void *dummyptr) {
printf("free-running\n");
// In this loop, we determine when the next CPU or Speaker event is;
// sleep until that event; and then perform the event. There are a
// number of maintenance tasks that also happen to be sure that
// peripherals are updated appropriately.
// In this loop, we determine when the next CPU event is; sleep until
// that event; and then perform the event. There are also peripheral
// maintenance calls embedded in the loop...
while (1) {
if (g_biosInterrupt) {
@ -140,55 +137,24 @@ static void *cpu_thread(void *dummyptr) {
do_gettime(&currentTime);
// FIXME: these first two can go in their respective loops after execution
// Determine the next speaker runtime (nextSpeakerCycle).
// The speaker runs 48 cycles behind the CPU (an arbitrary number).
timespec_add_cycles(&startTime, nextSpeakerCycle-48, &nextSpeakerCycleTime);
// Determine the next CPU runtime (nextInstructionTime)
timespec_add_cycles(&startTime, g_cpu->cycles, &nextInstructionTime);
// Sleep until one of them is ready to run.
// Sleep until the CPU is ready to run.
// tsSubtract doesn't return negatives; it bounds at zero. So if
// either result is zero then it's time to run something.
struct timespec cpudiff = tsSubtract(nextInstructionTime, currentTime);
struct timespec spkrdiff = tsSubtract(nextSpeakerCycleTime, currentTime);
struct timespec mindiff;
if (cpudiff.tv_sec < spkrdiff.tv_sec) {
memcpy(&mindiff, &cpudiff, sizeof(struct timespec));
} else if (spkrdiff.tv_sec < cpudiff.tv_sec) {
memcpy(&mindiff, &spkrdiff, sizeof(struct timespec));
} else if (cpudiff.tv_nsec < spkrdiff.tv_nsec) {
memcpy(&mindiff, &cpudiff, sizeof(struct timespec));
} else {
memcpy(&mindiff, &spkrdiff, sizeof(struct timespec));
}
if (mindiff.tv_sec > 0 || mindiff.tv_nsec > 0) {
// Sleep until the first of them is ready & loop...
nanosleep(&mindiff, NULL);
if (cpudiff.tv_sec > 0 || cpudiff.tv_nsec > 0) {
// Sleep until the it's ready and loop...
nanosleep(&cpudiff, NULL);
continue;
}
// Now we know either the speaker or the CPU is ready to
// run. Figure out which and run it.
if (spkrdiff.tv_sec == 0 && spkrdiff.tv_nsec == 0) {
// Run the speaker
uint64_t microseconds = nextSpeakerCycleTime.tv_sec * 1000000 +
(double)nextSpeakerCycleTime.tv_nsec / 1000.0;
g_speaker->maintainSpeaker(nextSpeakerCycle-48, microseconds);
nextSpeakerCycle++;
}
if (cpudiff.tv_sec == 0 && cpudiff.tv_nsec == 0) {
// Run the CPU
// Run the CPU; it's caught up to "real time"
uint8_t executed = 0;
if (debugger.active()) {
@ -288,6 +254,8 @@ int main(int argc, char *argv[])
// pthread_setschedparam(cpuThreadID, SCHED_RR, PTHREAD_MAX_PRIORITY);
}
g_speaker->begin();
uint32_t lastCycleCount = -1;
while (1) {
@ -311,8 +279,7 @@ int main(int argc, char *argv[])
do_gettime(&startTime);
do_gettime(&nextInstructionTime);
// Drain the speaker queue (FIXME: a little hacky)
g_speaker->maintainSpeaker(-1, -1);
// FIXME: drain whatever's in the speaker queue
/* FIXME
// Force the display to redraw

230
sdl/sdl-speaker.cpp
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@ -12,26 +12,37 @@ extern "C"
#include "timeutil.h"
// FIXME: 4096 is the right value here, I'm just debugging
#define SDLSIZE (4096)
// FIXME: Globals; ick.
static volatile uint32_t bufIdx = 0;
static uint8_t soundBuf[44100]; // 1 second of audio
static pthread_mutex_t sndmutex = PTHREAD_MUTEX_INITIALIZER;
static uint8_t soundBuf[44100];
static pthread_mutex_t togmutex = PTHREAD_MUTEX_INITIALIZER;
static struct timespec sdlEmptyTime, sdlStartTime;
extern struct timespec startTime; // defined in aiie (main)
static void audioCallback(void *unused, Uint8 *stream, int len)
{
pthread_mutex_lock(&sndmutex);
pthread_mutex_lock(&togmutex);
if (g_biosInterrupt) {
// While the BIOS is running, we don't put samples in the audio
// queue.
memset(stream, 0x80, len);
pthread_mutex_unlock(&sndmutex);
pthread_mutex_unlock(&togmutex);
return;
}
// calculate when the buffer will be empty again
do_gettime(&sdlEmptyTime);
timespec_add_us(&sdlEmptyTime, ((float)len * (float)1000000)/(float)44100, &sdlEmptyTime);
sdlEmptyTime = tsSubtract(sdlEmptyTime, sdlStartTime);
static uint8_t lastKnownSample = 0; // saved for when the apple is quiescent
if (bufIdx >= len) {
memcpy(stream, soundBuf, len);
lastKnownSample = stream[len-1];
if (bufIdx > len) {
// move the remaining data down
@ -39,17 +50,20 @@ static void audioCallback(void *unused, Uint8 *stream, int len)
bufIdx -= len;
}
} else {
// Audio underrun
static uint8_t occurrenceCount = 0;
if (++occurrenceCount < 10) {
printf("Audio underrun!\n");
if (occurrenceCount == 9) {
printf(" (Suppressing further audio errors)\n");
}
if (bufIdx) {
// partial buffer exists
memcpy(stream, soundBuf, bufIdx);
// and it's a partial underrun
memset(&stream[bufIdx], lastKnownSample, len-bufIdx);
bufIdx = 0;
} else {
// Total audio underrun. This is normal if nothing is toggling the
// speaker; we stay at the last known level.
memset(stream, lastKnownSample, len);
}
memset(stream, 0, len);
}
pthread_mutex_unlock(&sndmutex);
pthread_mutex_unlock(&togmutex);
}
void ResetDCFilter(); // FIXME: remove
@ -59,10 +73,7 @@ SDLSpeaker::SDLSpeaker()
toggleState = false;
mixerValue = 0x80;
toggleCount = toggleReadPtr = toggleWritePtr = 0;
pthread_mutex_init(&togmutex, NULL);
pthread_mutex_init(&sndmutex, NULL);
_init_darwin_shim();
@ -70,48 +81,112 @@ SDLSpeaker::SDLSpeaker()
lastCycleCount = 0;
lastSampleCount = 0;
SDL_AudioSpec audioDevice;
SDL_AudioSpec audioActual;
SDL_memset(&audioDevice, 0, sizeof(audioDevice));
audioDevice.freq = 44100;
audioDevice.format = AUDIO_U8;
audioDevice.channels = 1;
audioDevice.samples = 4096; // 4096 bytes @ 44100Hz is about 1/10th second out of sync - should be okay for this testing
audioDevice.callback = audioCallback;
audioDevice.userdata = NULL;
SDL_OpenAudio(&audioDevice, &audioActual); // FIXME retval
printf("Actual: freq %d channels %d samples %d\n",
audioActual.freq, audioActual.channels, audioActual.samples);
SDL_PauseAudio(0);
}
SDLSpeaker::~SDLSpeaker()
{
}
void SDLSpeaker::begin()
{
do_gettime(&sdlStartTime);
do_gettime(&sdlEmptyTime);
sdlEmptyTime = tsSubtract(sdlEmptyTime, sdlStartTime);
SDL_AudioSpec audioDevice;
SDL_AudioSpec audioActual;
SDL_memset(&audioDevice, 0, sizeof(audioDevice));
audioDevice.freq = 44100; // count of 8-bit samples
audioDevice.format = AUDIO_U8;
audioDevice.channels = 1;
audioDevice.samples = SDLSIZE; // SDLSIZE 8-bit samples @ 44100Hz: 4096 is about 1/10th second out of sync
audioDevice.callback = audioCallback;
audioDevice.userdata = NULL;
memset(&soundBuf[0], 0, SDLSIZE);
bufIdx = SDLSIZE/2;
SDL_OpenAudio(&audioDevice, &audioActual); // FIXME retval
printf("Actual: freq %d channels %d samples %d\n",
audioActual.freq, audioActual.channels, audioActual.samples);
SDL_PauseAudio(0);
}
void SDLSpeaker::toggle(uint32_t c)
{
pthread_mutex_lock(&togmutex);
toggleTimes[toggleWritePtr] = c;
if (toggleCount < SPEAKERQUEUESIZE-1) {
toggleWritePtr++;
if (toggleWritePtr >= SPEAKERQUEUESIZE)
toggleWritePtr = 0;
toggleCount++;
} else {
printf("speaker overflow @ cycle %d\n", c);
for (int i=0; i<SPEAKERQUEUESIZE; i++) {
printf(" %d [%d]\n", toggleTimes[(toggleReadPtr + i)%SPEAKERQUEUESIZE],
toggleTimes[(toggleReadPtr + i - 1)%SPEAKERQUEUESIZE] -
toggleTimes[(toggleReadPtr + i)%SPEAKERQUEUESIZE]
);
}
exit(1);
/* Figuring out what to do:
*
* The wallclock time we started the app is in startTime.
*
* The wallclock time when the SDL audio buffer will be totally
* drained is in sdlEmptyTime. When that time comes, we want to have
* at least SDLSIZE samples in soundBuf[] - which is currently filled
* to bufIdx samples.
*
* So given the cycle number at which this toggle happened (c), we
* know we need to fill soundBuf[bufIdx..?] with either 0 or 127
* (adjusted for volume). The end of that area that we need to fill is
* based on what time cycle 'c' refers to,
*
* The wallclock time of cycle (c) is calculable from
* timespec_add_cycles(&startTime, c, &outputTime);
*
* And the point at which the SDL buffer will be drained is the same
* as the time at which soundBuf begins. So the difference between
* the two tells us where the end point is.
*
* Then we need to fill soundBuf[bufIdx .. endPoint] with that 0 or 127,
* and set bufIdx = endPoint.
*
* Bonus: if it looks like we're not filling enough buffer, then we
* should tell the emulation layer above to run more cycles in bulk
* to build up more speaker backlog.
*/
// calculate the timespec that refers to the cycle where this
// speaker toggle happened
struct timespec blipTime;
timespec_add_cycles(&startTime, c, &blipTime);
timespec_add_us(&blipTime, ((float)SDLSIZE * (float)1000000)/(float)44100, &blipTime); // it's delayed one SDL buffer naturally, and there's some drift between the start of the CPU and the start of the speaker. :/
// determine how long there will be between the start of the buffer
// and that cycle time. (tsSubtract bounds at 0 and is never
// negative.)
struct timespec timeOffset = tsSubtract(blipTime, sdlEmptyTime);
// Turn that in to a sample index in the soundBuf[] buffer. There are 44100 of them per second,
// so this is straightforward
float newIdx = (float)timeOffset.tv_sec + ((float)timeOffset.tv_nsec / (float)NANOSECONDS_PER_SECOND);
newIdx *= 44100.0;
if (newIdx >= sizeof(soundBuf)) {
// Buffer overrun
printf("ERROR: buffer overrun, dropping data\n");
newIdx = sizeof(soundBuf)-1;
}
// Flip the toggle state
toggleState = !toggleState;
// Fill from bufIdx .. newIdx and set bufIdx to newIdx when done
if (newIdx > bufIdx) {
long count = (long)newIdx - bufIdx;
memset(&soundBuf[bufIdx], toggleState ? 127 : 0, count);
bufIdx = newIdx;
} else {
// Why are we backtracking? This does happen, and it's a bug.
if (newIdx >= 1) {
bufIdx = newIdx-1;
long count = (long)newIdx - bufIdx;
memset(&soundBuf[bufIdx], toggleState ? 127 : 0, count);
bufIdx = newIdx;
} else {
// ... and it's zero?
}
}
pthread_mutex_unlock(&togmutex);
}
@ -139,60 +214,6 @@ int16_t DCFilter(int16_t in)
void SDLSpeaker::maintainSpeaker(uint32_t c, uint64_t microseconds)
{
bool didChange = false;
pthread_mutex_lock(&togmutex);
if (c == -1 && microseconds == -1) {
// flushing
printf("Flush sound output\n");
toggleReadPtr = toggleWritePtr = 0;
toggleCount = 0;
} else {
while (toggleCount && c >= toggleTimes[toggleReadPtr]) {
// Override the mixer with a 1-bit "Terribad" audio sample change
toggleState = !toggleState;
toggleCount--;
toggleReadPtr++;
if (toggleReadPtr >= SPEAKERQUEUESIZE)
toggleReadPtr = 0;
didChange = true;
}
}
pthread_mutex_unlock(&togmutex);
// FIXME: removed all the mixing code
// Add samples from the last time to this time
// mixerValue = (toggleState ? 0x1FF : 0x00);
mixerValue = (toggleState ? 0x00 : ~0x80);
// FIXME: DC filter isn't correct yet
// mixerValue = DCFilter(mixerValue);
uint64_t sampleCount = (microseconds * 44100) / 1000000;
uint64_t numSamples = sampleCount - lastSampleCount;
if (numSamples) {
lastSampleCount = sampleCount;
pthread_mutex_lock(&sndmutex);
if (bufIdx + numSamples >= sizeof(soundBuf)) {
static uint8_t errcnt = 0;
if (++errcnt <= 10) {
printf("Sound overrun!\n");
}
numSamples = sizeof(soundBuf) - bufIdx - 1;
}
mixerValue >>= (8-(g_volume/2));
memset(&soundBuf[bufIdx], mixerValue, numSamples);
bufIdx += numSamples;
pthread_mutex_unlock(&sndmutex);
}
}
void SDLSpeaker::beginMixing()
@ -202,3 +223,8 @@ void SDLSpeaker::beginMixing()
void SDLSpeaker::mixOutput(uint8_t v)
{
}
uint32_t SDLSpeaker::bufferedContentSize()
{
return bufIdx;
}

10
sdl/sdl-speaker.h
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@ -12,19 +12,19 @@ class SDLSpeaker : public PhysicalSpeaker {
SDLSpeaker();
virtual ~SDLSpeaker();
virtual void begin();
virtual void toggle(uint32_t c);
virtual void maintainSpeaker(uint32_t c, uint64_t microseconds);
virtual void beginMixing();
virtual void mixOutput(uint8_t v);
virtual uint32_t bufferedContentSize();
private:
uint8_t mixerValue;
bool toggleState;
uint32_t toggleTimes[SPEAKERQUEUESIZE];
uint8_t toggleCount; // # of entries still in queue
uint8_t toggleReadPtr; // ring buffer pointer in queue
uint8_t toggleWritePtr; // ring buffer pointer in queue
uint64_t lastCycleCount;
uint64_t lastSampleCount;
};