def bin2hex(s):
    ht = [ str(i) for i in range(10) ] + [ "A","B","C","D","E","F" ]
    h = ""
    while s != "":
        h = ht[int(s[-4:],2)] + h
        s = s[:-4]
    return "0x"+h

def to_mantisse(d,n=23):
    s = ""
    for i in range(n):
        d *= 2
        s += str(int(d)%2)
    return s

def to_binary(d,n=8):
    s = ""
    for i in range(n):
        s = str(d & 1) + s
        d = d >> 1
    return s

def to_ieee754(d,el,ml):
    if d < 0:
        s = 1
        d *= -1
    else:
        s = 0
    g = 0
    while d >= 2:
        d /= 2
        g += 1
    while d <= 0.5:
        d *= 2
        g -= 1
    bias = 2**(el-1)-1
    e = g+bias
    return str(s)+to_binary(e,n=el)+to_mantisse(d,n=ml)

def to_ieee754_single(d):
    return to_ieee754(d,el=8,ml=23)

def to_ieee754_double(d):
    return to_ieee754(d,el=11,ml=52)

def to_ieee754_single_hex(d):
    return bin2hex(to_ieee754_single(d))

def to_ieee754_double_hex(d):
    return bin2hex(to_ieee754_double(d))

if __name__ == "__main__":
    print(bin2hex(to_ieee754_double(-2.5)))
    print(bin2hex(to_ieee754_double(-1.75)))