#include "system/task_rand.h"
#include "system/hardware_task.h"
#include "system/data_channel.h"
#include "system/float_word.h"
#include <stdio.h>
#include <stdlib.h>

int data_channel_read(uint32_t base, uint32_t * value);
int data_channel_write(uint32_t base, uint32_t value);


float generate_value(uint32_t lfsr)
{
    union {
        uint32_t u;
        float f;
    } v;

    uint32_t S = (lfsr >> 31) & 0x01u; // Sign
    uint32_t M = lfsr & 0x007FFFFFu; // Mantisse
    uint32_t E;
    uint32_t E_ = (lfsr >> 23) & 0xFFu;

    if (E_ & 0x80u) {
        // 128 or 129
        E = (0x80u) | (E_ & 0x01u);
    } else {
        // 124..127
        E = (0x7Cu) | (E_ & 0x03u);
    }

    // Zusammensetzen
    v.u = (S << 31) | (E << 23) | M;

    return v.f;
}

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);
	//srand(time(NULL));
	float_word seed = { .value = config->seed};
	uint32_t lfsr = seed.word;
	for (uint32_t i = 0; i< DATA_CHANNEL_DEPTH; ++i){
		float_word res;
		res.value = generate_value(lfsr);
		data_channel_write(data_channel_base, res.word);
		uint32_t fb = ((lfsr >> 31) ^ (lfsr >> 21) ^ (lfsr >> 1) ^ (lfsr >> 0)) & 0x1u;
		lfsr = (lfsr << 1) | fb;
	}
    
    return 0;
}