'Target machine word size, in bits (i.e. the size of general purpose registers).
The default value is ``32``, but changes according to :attr:`arch`.
Examples:
>>> context.clear()
>>> context.bits == 32
True
>>> context.bits = 64
>>> context.bits == 64
True
>>> context.bits = -1 #doctest: +ELLIPSIS
Traceback (most recent call last):
AttributeError: bits must be > 0 (-1)'

@_validator
def bits(self, bits):

    bits = int(bits)
    if (bits <= 0):
        raise AttributeError(('bits    must    be    >    0    (%r)' % bits))
    return bits
