IEEE_754_1985_FPR.py

#!/usr/bin/env python
# IEEE-754-1985
# Dario Clavijo 2018
# GPLv2
verbose = False


def ieee_754_1985_32(i):
    # single precision floating point
    # SEEEEEEEEMMMMMMMMMMMMMMMMMMMMMMM
    S = i >> 31
    E = (i >> 23) & 0b11111111
    F = i & 0b11111111111111111111111
    a = -(1**S)
    b = 1.0 + ((1.0 * F) / (2**23))
    c = 2 ** (E - 127)
    if verbose:
        print(bin(s), bin(E), bin(F))
        print(a, b, c)
    return a * b * c


def ieee_754_1985_64(i):
    # double precision floating point
    # SEEEEEEEEEEEMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
    S = i >> 63
    E = (i >> 52) & 0b11111111111
    F = i & 0b1111111111111111111111111111111111111111111111111111
    a = -(1**S)
    b = 1.0 + ((1.0 * F) / (2**52))
    c = 2 ** (E - 1023)
    if verbose:
        print(bin(s), bin(E), bin(F))
        print(a, b, c)
    return a * b * c


def test():
    pi = 3.141592653589793
    print(pi)
    pi32 = 0b01000000010010010000111111011011
    pi64 = 0b0100000000001001001000011111101101010100010001000010110100011000
    print(pi32, hex(pi32))
    print(pi64, hex(pi64))
    print(ieee_754_1985_32(pi32))
    print(ieee_754_1985_64(pi64))


test()