def sub(clock, write, address, data_in):
assert len(address) >= 2
address = address[:2]
control_lines = address_decode(address)
write_a = And(clock, write, control_lines[0])
a = register(data_in, write_a)
write_b = And(clock, write, control_lines[1])
b = register(data_in, write_b)
res, carry = ripple_subtractor(a, b)
carry = pad([carry], len(data_in))
return word_switch(control_lines, a, b, res, carry)
def test_ripple_subtractor():
network = core.Network()
a = test_utils.BinaryIn(network, 8)
b = test_utils.BinaryIn(network, 8)
r, c = adders.ripple_subtractor(a, b)
r = test_utils.BinaryOut(r)
for i in range(10):
v1 = random.randrange(256)
v2 = random.randrange(256)
print v1, v2
a.write(v1)
b.write(v2)
network.drain()
assert c.read() == (v1 < v2)
assert r.read() == (v1 - v2) % 256
def test_ripple_subtractor():
network = core.Network()
a = test_utils.BinaryIn(network, 8)
b = test_utils.BinaryIn(network, 8)
r, c = adders.ripple_subtractor(a, b)
r = test_utils.BinaryOut(r)
for i in range(10):
v1 = random.randrange(256)
v2 = random.randrange(256)
print(v1, v2)
a.write(v1)
b.write(v2)
network.drain()
assert c.read() == (v1 < v2)
assert r.read() == (v1 - v2) % 256