#include "system/task_rand.h"
#include "system/hardware_task.h"
#include "system/data_channel.h"
#include "system/float_word.h"

int task_rand_run(void *task)
{
    rand_config *config = (rand_config *)task;

    uint32_t data_channel_base = config->base.sink;
    data_channel_clear(data_channel_base);

    float_word seed_fw = { .value = config->seed };
    uint32_t lfsr = seed_fw.word;

    for (uint32_t i = 0; i < DATA_CHANNEL_DEPTH; ++i) {

        uint32_t sign     = (lfsr >> 31) & 0x1u;
        uint32_t mant     =  lfsr        & 0x007FFFFFu;   // 23 Bit Mantisse
        uint32_t exp_rand = (lfsr >> 23) & 0xFFu;         // 8 Bit Exponent

        uint32_t exp_new;
        if (exp_rand & 0x80u) {
            exp_new = 0x80u | (exp_rand & 0x01u);
        } else {
            exp_new = 0x7Cu | (exp_rand & 0x03u);
        }

        float_word out;
        out.word = (sign << 31) | (exp_new << 23) | mant;

        data_channel_write(data_channel_base, out.word);

        uint32_t fb = ((lfsr >> 31) ^ (lfsr >> 21) ^ (lfsr >> 1) ^ (lfsr >> 0)) & 0x1u;
        lfsr = (lfsr << 1) | fb;
    }

    return 0;
}