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I'm testing a project on a signal processing processor (ADSP 21489). I'm using as a development software VisualDSP++ 5.0 from Analog Devices. I use the DMA buffers to send data to a CODEC.

The problem is that in Debug mode everything is fine, but in Release mode it's not working. The compiler optimizes something that shouldn't be optimized. I tried making the variables volatile and adding #pragma optimize_off, but still didn't work. Any tips how this can be resolved?

extern volatile int inputReady;
extern volatile int buffer_cntr;

static void fixData (int *output, float *input, unsigned int outstep, unsigned int length)
{
    int i;

    for(i = 0; i < length; i++)
    {
        output[outstep*i] = __builtin_conv_FtoR(input[i]);
    }
}

#pragma optimize_off
volatile int sine_cnt = 0;

static void process_audioBlocks(void)
{
    memcpy(fBlockA.Tx_L1, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_R1, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_L2, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_R2, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_R3, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_L3, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_L4, &sine[sine_cnt], DAC_NUM_SAMPLES);
    memcpy(fBlockA.Tx_R4, &sine[sine_cnt], DAC_NUM_SAMPLES);
    
    if (sine_cnt < ARRAY_SIZE(sine) - DAC_NUM_SAMPLES)
    {
        sine_cnt += DAC_NUM_SAMPLES;
    }
    else
    {
        sine_cnt = 0;
    }
}
#pragma optimize_as_cmd_line

#pragma optimize_off
void AD1938_ISR(int sig_int)
{
    int i;
       
    if(isProcessing)
    {
        ProcessingTooLong();
    }
    else
    {
        //Increment the block pointer
        buffer_cntr++;
        buffer_cntr %= 2;
        inputReady = 1;
    }
}
#pragma optimize_as_cmd_line

#pragma optimize_off
void AD1938_Handle_Codec_Data(volatile int buffer_cntr)
{
    // Clear the Block Ready Semaphore
    inputReady = 0;

    // Set the Processing Active Semaphore before starting processing
    isProcessing = 1;

    // Place the audio processing algorithm here. 
    process_audioBlocks();

    // Fix DAC data for AD1938
    fixData(tx_block_pointer[buffer_cntr]+0, fBlockA.Tx_L1, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+1, fBlockA.Tx_R1, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+2, fBlockA.Tx_L2, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+3, fBlockA.Tx_R2, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+4, fBlockA.Tx_L3, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+5, fBlockA.Tx_R3, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+6, fBlockA.Tx_L4, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    fixData(tx_block_pointer[buffer_cntr]+7, fBlockA.Tx_R4, NUM_TX_SLOTS, DAC_NUM_SAMPLES);
    
    // Clear the Processing Active Semaphore after processing is complete
    isProcessing = 0;
}
#pragma optimize_as_cmd_line

This is part of my code. The AD1938_ISR is a interrupt handler which initiates the transfer. The tx_block_pointer contains pointers to the dma buffer (ping-pong transfer mode).

Improve this question
4
  • hello , no need to put everything volatile , but i was wondering could you post the definition of the isProcessing variable ? This is typically the kind of usage where the optimisation would change the intended behaviour. Commented Oct 18, 2016 at 11:25
  • isProcessing variable is defined globaly as a volatile integer (volatile int isProcessing = 0). If isProcessing == 1 when the interrupt arrives (the processing takes too long) the program will be stuck in a infinite loop ( the function void ProcessingTooLong(void) { printf("\nError: Audio processing too long"); while(1); }) Commented Oct 19, 2016 at 11:20
  • isProcessing is a semaphore to indicate to the isr that the processing has not completed before the buffer will be overwritten. Commented Oct 19, 2016 at 11:24
  • It looks like some modifications from an exemple code from installation package of VisualDSP++... can you tell what was the initial example (before you change anything)? Commented Nov 25, 2016 at 15:08
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