eris_mixer_ext.cpp

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#include "eris_mixer_ext.h"
#include <dspinst.h>
 
 
 
static void applyGain2(int16_t *data, int32_t mult)
{
    uint32_t *p = (uint32_t *)data;
    const uint32_t *end = (uint32_t *)(data + AUDIO_BLOCK_SAMPLES);
 
    do {
        uint32_t tmp32 = *p; // read 2 samples from *data
        int32_t val1 = signed_multiply_32x16b(mult, tmp32);
        int32_t val2 = signed_multiply_32x16t(mult, tmp32);
        val1 = signed_saturate_rshift(val1, 16, 0);
        val2 = signed_saturate_rshift(val2, 16, 0);
        *p++ = pack_16b_16b(val2, val1);
    } while (p < end);
}
 
static void applyGainThenAdd2(int16_t *data, const int16_t *in, int32_t mult)
{
    uint32_t *dst = (uint32_t *)data;
    const uint32_t *src = (uint32_t *)in;
    const uint32_t *end = (uint32_t *)(data + AUDIO_BLOCK_SAMPLES);
 
    if (mult == 65536) {
        do {
            uint32_t tmp32 = *dst;
            *dst++ = signed_add_16_and_16(tmp32, *src++);
            tmp32 = *dst;
            *dst++ = signed_add_16_and_16(tmp32, *src++);
        } while (dst < end);
    } else {
        do {
            uint32_t tmp32 = *src++; // read 2 samples from *data
            int32_t val1 = signed_multiply_32x16b(mult, tmp32);
            int32_t val2 = signed_multiply_32x16t(mult, tmp32);
            val1 = signed_saturate_rshift(val1, 16, 0);
            val2 = signed_saturate_rshift(val2, 16, 0);
            tmp32 = pack_16b_16b(val2, val1);
            uint32_t tmp32b = *dst;
            *dst++ = signed_add_16_and_16(tmp32, tmp32b);
        } while (dst < end);
    }
}
 
 
void AudioMixer8::update(void)
{
    audio_block_t *in, *out=NULL;
    unsigned int channel;
 
    for (channel=0; channel < 8; channel++) {
        if (!out) {
            out = receiveWritable(channel);
            if (out) {
                int32_t mult = multiplier[channel];
                if (mult != 65536) applyGain2(out->data, mult);
            }
        } else {
            in = receiveReadOnly(channel);
            if (in) {
                applyGainThenAdd2(out->data, in->data, multiplier[channel]);
                release(in);
            }
        }
    }
    if (out) {
        transmit(out);
        release(out);
    }
}