#include "addition.h"
#include <stdlib.h>

// Struct for number in floating and integer 

struct data
{
    union {
        float floating;
        unsigned int integer;
    } number;
    unsigned int sign;
    unsigned int exponent;
    unsigned int precision;
};

// full_adder is an implementation of two bit addition with carry

void full_adder (num* sum, num* nextcarry, num number1, num number2, num carry) {
    sum[0] = (number1 % 2) ^ (number2 % 2) ^ (carry % 2);
    
    nextcarry[0] = ((number1 % 2) & (number2 % 2)) | ((number1 % 2) & (carry % 2)) | ((number2 % 2) & (carry % 2));
}

// addition is an implementation of an 32 bit addition

unsigned int addition_uint(num number1, num number2) {
    unsigned int result = 0;
    num sum[1] = {0};
    num nextcarry[1] = {0};

    for (int i = 0; i < 8 * sizeof(num); i++)
    {
        full_adder(sum, nextcarry, number1, number2, nextcarry[0]);
        result ^= (sum[0] << i);

        number1 >>= 1;
        number2 >>= 1;
    }

    return result;
}

// reading sign out of an integer (floating number)

unsigned int sign_float(unsigned int number) {
    return number >> 31;
}

// reading precision out of an integer (floating number)

unsigned int precision_float(unsigned int number) {
    unsigned int precision = 8388607;
    return (number & precision);
}

// reading exponent out of an integer (floating number)

unsigned int exponent_float(unsigned int number) {
    unsigned int exponent = 2139095040;
    return (number & exponent) >> 23;
}

// adding two precision together

unsigned int addition_precision_float(unsigned int p1, unsigned int p2) {
    return addition_uint(p1, p2);
}

// writing number out of sign, exponent and precision

unsigned int output_float(unsigned int sign, unsigned int exponent, unsigned int precision) {
    return (sign << 31) | (exponent << 23) | precision;
}

// addition of two floating numbers

float addition_float(float number1, float number2) {
    if (number2 == (float) 0.0) return number1;
    else if (number1 == (float) 0.0) return number2;
    else if (number2 > number1) return addition_float(number2, number1);

    unsigned int e = 8388608;
    struct data num1, num2, num3;
    num1.number.floating = number1, num2.number.floating = number2;
    num1.sign = sign_float(num1.number.integer), num2.sign = sign_float(num2.number.integer);
    num1.exponent = exponent_float(num1.number.integer), num2.exponent = exponent_float(num2.number.integer);
    num1.precision = precision_float(num1.number.integer) | e, num2.precision = precision_float(num2.number.integer) | e;

    num3.precision = addition_precision_float(num1.precision, num2.precision >> (num1.exponent - num2.exponent));
    if (num3.precision > 16777215) {
        num3.exponent = addition_uint(num1.exponent, 1);
        num3.precision = (num3.precision >> 1);
    }
    else {
        num3.exponent = num1.exponent;
    }
    num3.precision ^= e;
    num3.number.integer = output_float(num1.sign, num3.exponent, num3.precision);

    return num3.number.floating;
}