def reset(self, machine):
transform.Transform.reset(self, machine)
word_size = self.get_word_size()
bits = machine.addr_bits - util.get_bus_shift(word_size)
while self.shift < 0:
self.shift += bits
self.shift %= bits
def random_shift(machine, nxt, rand):
word_size = nxt.get_word_size()
word_bits = util.get_bus_shift(word_size)
bits = machine.addr_bits - word_bits - 1
shift = rand.randint(-bits, bits)
result = Shift(join.Join(), nxt, shift)
result.reset(machine)
return result
def _rotate(self, value, count):
word_size = self.get_word_size()
word_bits = util.get_bus_shift(word_size)
word_mask = word_size - 1
bits = self.machine.addr_bits - word_bits
mask = (1 << bits) - 1
shift_part = value >> word_bits
word_part = value & word_mask
if count >= 0:
count2 = bits - count
shifted = ((shift_part << count) & mask) | (shift_part >> count2)
else:
count2 = bits + count
shifted = ((shift_part << count2) & mask) | (shift_part >> -count)
return (shifted << word_bits) | word_part
def get_addr_width(self, word_size):
"""Get the number of bits needed for an address bus."""
return self.addr_bits - util.get_bus_shift(word_size)
def permute(self, rand):
word_bits = util.get_bus_shift(self.get_word_size())
bits = self.machine.addr_bits - word_bits - 1
self.shift = rand.randint(-bits, bits)
return True
