size_t fifo_read(int16_t *buffer, size_t samples, sim_t *s)
{
size_t length;
size_t samples_remaining;
int16_t *buffer_current = buffer;
length = get_sample_length(s);
if (length < samples)
samples = length;
length = samples; // return value
samples_remaining = FIFO_LENGTH - s->tail;
if (samples > samples_remaining) {
memcpy(buffer_current, &(s->fifo[s->tail * 2]), samples_remaining * sizeof(int16_t) * 2);
s->tail = 0;
buffer_current += samples_remaining * 2;
samples -= samples_remaining;
}
memcpy(buffer_current, &(s->fifo[s->tail * 2]), samples * sizeof(int16_t) * 2);
s->tail += (long)samples;
if (s->tail >= FIFO_LENGTH)
s->tail -= FIFO_LENGTH;
return(length);
}
void *tx_task(void *arg)
{
sim_t *s = (sim_t *)arg;
size_t samples_populated;
while (1) {
int16_t *tx_buffer_current = s->tx.buffer;
unsigned int buffer_samples_remaining = SAMPLES_PER_BUFFER;
while (buffer_samples_remaining > 0) {
pthread_mutex_lock(&(s->gps.lock));
while (get_sample_length(s) == 0)
{
pthread_cond_wait(&(s->fifo_read_ready), &(s->gps.lock));
}
// assert(get_sample_length(s) > 0);
samples_populated = fifo_read(tx_buffer_current,
buffer_samples_remaining,
s);
pthread_mutex_unlock(&(s->gps.lock));
pthread_cond_signal(&(s->fifo_write_ready));
#if 0
if (is_fifo_write_ready(s)) {
/*
printf("\rTime = %4.1f", s->time);
s->time += 0.1;
fflush(stdout);
*/
}
else if (is_finished_generation(s))
{
goto out;
}
#endif
// Advance the buffer pointer.
buffer_samples_remaining -= (unsigned int)samples_populated;
tx_buffer_current += (2 * samples_populated);
}
// If there were no errors, transmit the data buffer.
bladerf_sync_tx(s->tx.dev, s->tx.buffer, SAMPLES_PER_BUFFER, NULL, TIMEOUT_MS);
if (is_fifo_write_ready(s)) {
/*
printf("\rTime = %4.1f", s->time);
s->time += 0.1;
fflush(stdout);
*/
}
else if (is_finished_generation(s))
{
goto out;
}
}
out:
return NULL;
}
int is_fifo_write_ready(sim_t *s)
{
int status = 0;
s->sample_length = get_sample_length(s);
if (s->sample_length < NUM_IQ_SAMPLES)
status = 1;
return(status);
}