handy functions to work with bits

bitutils.py

# (unset) mask = 0xff - (1 << offset) if (nibble == 'lower') else 0xff - (4 << (4 - offset)); operation = &
# (set) mask = 1 << offset if (nibble == 'lower') else 4 << (4 - offset); operation = |
#
# (read) result = (current_values & 0x0F) if (nibble == 'lower') else (current_values & 0xF0) >> 4
# (write) mask = (offset - 1) & 0xf0 if (nibble == 'lower') else 4 << (offset - 1) & 0x0f; operation = |

def getNibbles(int_type):
  """ getNibbles() returns the byte nibbles for a given integer (upper, lower) """
    return((int_type & 0xF0) >> 4, (int_type & 0x0F))

def testBit(int_type, offset):
  """ testBit() returns a nonzero result, 2**offset, if the bit at 'offset' is one. """
    mask = 1 << offset
    return(int_type & mask)

def setBit(int_type, offset):
  """ setBit() returns an integer with the bit at 'offset' set to 1. """"
    mask = 1 << offset
    return(int_type | mask)

def clearBit(int_type, offset):
    """ clearBit() returns an integer with the bit at 'offset' cleared."""
    mask = ~(1 << offset)
    return(int_type & mask)

def toggleBit(int_type, offset):
  """ toggleBit() returns an integer with the bit at 'offset' inverted, 0 -> 1 and 1 -> 0."""
    mask = 1 << offset
    return(int_type ^ mask)