sample.hcc

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/******** System Includes *************/

/******** Application Includes ********/
#include "sample.hch"



/*
 * Pointer that points towards the current 64 bits samples.
 */
signed 16 *audio_in_ptr;

/*
 * 64 step counter to keep track of our samples. This is a private variable.
 */
unsigned 8 sample_count;



void sample_add(signed 16 in_sample) {
        /*
         * We only sample 64 bits in our buffer, hence we circulate around the
         * last 6 bits.
         */
        audio_in_ptr[sample_count <-6] = in_sample;
        sample_count++;
} /* --- sample_add() --- */



void sample_get(signed 16 *out_sample) {
        /*
         * We circulate around a 64 bits buffer, therefor we only use the last
         *  6 bits.
         */
        *out_sample = audio_out_ptr[sample_count <-6];
} /* --- sample_get() --- */



unsigned 1 sample_rotate_buffers(void) {
        unsigned 1 retval;      /* store for returnvalue */

        retval = 0;
        /*
         * We only want to read 64 samples, but calculations work nicer if we
         * use 256 samples. Therefor we circulate our audio pointer around.
         */
        if (!(sample_count <- 6)) {
                /*
                 * 64 Samples have passed. We are back at '0'. Use the full
                 * sample count as index which is 0 64 128 or 192 and back to
                 * 0. Our Output is only 128 big so we only look at the
                 * 7 LSB. Also, notify the main application that 64 samples
                 * have been processed.
                 */
                par {
                        audio_in_ptr = &pcm_audio_in[sample_count];
                        audio_out_ptr = &pcm_audio_out[(sample_count <- 7)];
                        retval = 1;
                }
        }
} /* --- sample_rotate_buffers() --- */

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