def bitfield_update_checker(self,
input_width,
range_start,
range_end,
update_width,
test_amt=20):
def ref(i, s, e, u):
mask = ((1 << (e)) - 1) - ((1 << s) - 1)
return (i & ~mask) | ((u << s) & mask)
inp, inp_vals = utils.an_input_and_vals(input_width,
test_vals=test_amt,
name='inp')
upd, upd_vals = utils.an_input_and_vals(update_width,
test_vals=test_amt,
name='upd')
#inp_vals = [1,1,0,0]
#upd_vals = [0x7,0x6,0x7,0x6]
out = pyrtl.Output(input_width, "out")
bfu_out = pyrtl.bitfield_update(inp, range_start, range_end, upd)
self.assertEqual(len(out),
len(bfu_out)) # output should have width of input
out <<= bfu_out
true_result = [
ref(i, range_start, range_end, u)
for i, u in zip(inp_vals, upd_vals)
]
upd_result = utils.sim_and_ret_out(out, [inp, upd],
[inp_vals, upd_vals])
self.assertEqual(upd_result, true_result)
def test_field_too_big_truncate(self):
a = pyrtl.WireVector(name='a', bitwidth=3)
b = pyrtl.WireVector(name='b', bitwidth=3)
o = pyrtl.bitfield_update(a, 1, 2, b, truncating=True)
def test_no_bits_to_update(self):
a = pyrtl.WireVector(name='a', bitwidth=3)
b = pyrtl.WireVector(name='b', bitwidth=3)
with self.assertRaises(pyrtl.PyrtlError):
o = pyrtl.bitfield_update(a, 1, 1, b, truncating=True)
def test_field_too_big(self):
a = pyrtl.WireVector(name='a', bitwidth=3)
b = pyrtl.WireVector(name='b', bitwidth=3)
with self.assertRaises(pyrtl.PyrtlError):
o = pyrtl.bitfield_update(a, 1, 2, b)