diff --git a/examples/example1.1-signed-numbers.py b/examples/example1.1-signed-numbers.py index 572c5a91..d4b45e9c 100644 --- a/examples/example1.1-signed-numbers.py +++ b/examples/example1.1-signed-numbers.py @@ -89,9 +89,8 @@ # Manually sign-extend inputs to correctly add signed integers with `+`. # ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ # Instead of using `signed_add`, we can manually sign-extend the inputs and -# truncate the output to correctly add signed integers with `+`. -# -# Use this trick to implement other signed arithmetic operations. +# truncate the output to correctly add signed integers with `+`. Use this trick +# to implement other signed arithmetic operations. pyrtl.reset_working_block() a = pyrtl.Input(bitwidth=2, name='a') @@ -100,8 +99,8 @@ # Using `+` produces the correct result for signed addition here because we # manually extend `a` and `b` to 3 bits. The result of `a.sign_extended(3) + # b.sign_extended(3)` is now 4 bits, but we truncate it to 3 bits. This -# truncation is important! The addition's full 4 bit result would not be -# correct. +# truncation is subtle, but important! The addition's full 4 bit result would +# not be correct. sign_extended_sum = pyrtl.Output(bitwidth=3, name='sign_extended_sum') extended_a = a.sign_extended(bitwidth=3) extended_b = b.sign_extended(bitwidth=3) @@ -117,5 +116,6 @@ print('\nInstead of using `signed_add`, we can also manually sign extend the ' 'inputs to\ncorrectly add signed integers with `+`.\n' - 'sign_extended_sum == a.sign_extended(3) + b.sign_extended(3)') + 'sign_extended_sum == (a.sign_extended(3) + b.sign_extended(3))' + '.truncate(3)') sim.tracer.render_trace(repr_func=pyrtl.val_to_signed_integer) diff --git a/examples/example2-counter.py b/examples/example2-counter.py index 94464c92..eb92c811 100644 --- a/examples/example2-counter.py +++ b/examples/example2-counter.py @@ -80,7 +80,3 @@ def ripple_add(a, b, carry_in=0): sim.step({}) assert sim.value[counter] == cycle % 8 sim_trace.render_trace() - -# All done. - -exit(0) diff --git a/pyrtl/wire.py b/pyrtl/wire.py index 1ac526a1..89783599 100644 --- a/pyrtl/wire.py +++ b/pyrtl/wire.py @@ -305,7 +305,7 @@ def __ixor__(self, other): def __add__(self, other): """Adds two wires together into a single WireVector. - Addition is *unsigned*. + Addition is *unsigned*. Use :func:`.signed_add` for signed addition. :rtype: WireVector :return: Returns the result wire of the operation. The resulting wire @@ -330,7 +330,8 @@ def __iadd__(self, other): def __sub__(self, other): """Subtracts the right wire from the left one. - Subtraction is *unsigned*. + Subtraction is *unsigned*. Use :func:`.signed_sub` for signed + subtraction. :rtype: WireVector :return: Returns the result wire of the operation. The resulting wire @@ -350,7 +351,8 @@ def __isub__(self, other): def __mul__(self, other): """Multiplies two WireVectors. - Multiplication is *unsigned*. + Multiplication is *unsigned*. Use :func:`.signed_mult` for signed + multiplication. :rtype: WireVector :return: Returns the result wire of the operation. The resulting wire's @@ -368,7 +370,8 @@ def __imul__(self, other): def __lt__(self, other): """Calculates whether a wire is less than another. - The comparison is *unsigned*. + The comparison is *unsigned*. Use :func:`.signed_lt` for a signed + comparison. :rtype: WireVector :return: a one bit result wire of the operation @@ -379,7 +382,8 @@ def __lt__(self, other): def __le__(self, other): """Calculates whether a wire is less than or equal to another. - The comparison is *unsigned*. + The comparison is *unsigned*. Use :func:`.signed_le` for a signed + comparison. :rtype: WireVector :return: a one bit result wire of the operation @@ -408,7 +412,8 @@ def __ne__(self, other): def __gt__(self, other): """Calculates whether a wire is greater than another. - The comparison is *unsigned*. + The comparison is *unsigned*. Use :func:`.signed_gt` for a signed + comparison. :rtype: WireVector :return: a one bit result wire of the operation @@ -419,7 +424,8 @@ def __gt__(self, other): def __ge__(self, other): """Calculates whether a wire is greater than or equal to another. - The comparison is *unsigned*. + The comparison is *unsigned*. Use :func:`.signed_ge` for a signed + comparison. :rtype: WireVector :return: a one bit result wire of the operation