Double compare

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>

typedef int64_t s64;
typedef uint64_t u64;
typedef int64_t s8;
typedef double f64;
typedef bool b8;


u64 f64Tos64(f64 a)
{
    s64 Result = *((s64 *)&a);
    return Result;
}
f64 s64Tof64(s64 a)
{
    f64 Result = *((f64 *)&a);
    return Result;
}

b8 Compare(f64 in_a, f64 in_b, s8 Shift)
{
    s64 a = f64Tos64(in_a);
    s64 b = f64Tos64(in_b);
    
    // Verify:
    // How exponet reacts.
    // Compare on exponet first?
    // Assert shift is no higher than mantissa.
    return labs(a-b) <= (2 << Shift);
}


int main()
{
    f64 a = 0.30000000000001; // Equal
//  f64 a = 0.3000000000001; // Not Equal
    f64 b = 0.3;
    
    printf("%f\n",a);
    printf("%lx\n",f64Tos64(a));
    printf("%f\n",b);
    printf("%lx\n",f64Tos64(b));
    
    printf("%li\n",f64Tos64(3.0) - f64Tos64(0.3));
    printf("-0.0 - 0.0: %li\n",f64Tos64(-0.0) - f64Tos64(0.0)); // Problems :(
    printf("%li\n",Compare(f64Tos64(-0.0), f64Tos64(0.0), 8));
    
    
    
    if(Compare(b,a,8))
    {
        printf("yay?\n");
    }
    else
    {
        printf("nay\n");
    }
    return 0;
}