IEEE 754

ieee754.py

import struct

from_hex = lambda hx: struct.unpack('>f', struct.pack('>I', hx))[0]
to_hex = lambda dc: '0x' + ''.join(['%.2x' % ord(x) for x in struct.pack('>f', dc)])
chr_to_bin = lambda ch: ('0'*8 + bin(ord(ch))[2:])[-8:]
to_32_bits = lambda fl: '|'.join((lambda bits: [bits[:1], bits[1:9], bits[9:]])(''.join(map(chr_to_bin, struct.pack('>f', fl)))))
to_64_bits = lambda fl: '|'.join((lambda bits: [bits[:1], bits[1:12], bits[12:]])(''.join(map(chr_to_bin, struct.pack('>d', fl)))))
from_bits = lambda bs: from_hex(int(bs.replace('|', ''), 2))

a = 0xfb
b = from_hex(0x80004800)
c = a * b

print to_32_bits(a)
# 0|10000110|11110110000000000000000
print to_32_bits(b)
# 1|00000000|00000000100100000000000
print to_32_bits(c)
# 1|00000000|10001101001100000000000
print to_64_bits(c)
# 1|01110000000|0001101001100000000000000000000000000000000000000000
print to_hex(c)
# 0x80469800
print from_bits('1|00000000|00000000100100000000000')
# -2.582873329443503e-41

print to_32_bits(0.0)
# 0|00000000|00000000000000000000000
print to_32_bits(-0.0)
# 1|00000000|00000000000000000000000
print to_32_bits(float('infinity'))
# 0|11111111|00000000000000000000000
print to_32_bits(float('-infinity'))
# 1|11111111|00000000000000000000000
print to_32_bits(float('nan'))
# 0|11111111|10000000000000000000000
print to_32_bits(float('-nan'))
# 1|11111111|10000000000000000000000

Tisti, ki boste uporabljal tole skripto za preverjanje rezultata pri 2. domači nalogi za ars, namesto 0xfb(ki je zapisan s dvojiškim komplementom), pišite -0x5 in boste dobili pravilno rešitev.