def popcount(w):
"""
Create a population count circuit.
Parameters
----------
w : int
Input width of the circuit.
Returns
-------
Circuit
Population count circuit.
"""
c = Circuit(name="popcount")
ps = [[c.add(f"in_{i}", "input")] for i in range(w)]
c.add("tie0", "0")
i = 0
while len(ps) > 1:
# get values
ns = ps.pop(0)
ms = ps.pop(0)
# pad
aw = max(len(ns), len(ms))
while len(ms) < aw:
ms += ["tie0"]
while len(ns) < aw:
ns += ["tie0"]
# instantiate and connect adder
c.add_subcircuit(adder(aw), f"add_{i}")
for j, (n, m) in enumerate(zip(ns, ms)):
c.connect(n, f"add_{i}_a_{j}")
c.connect(m, f"add_{i}_b_{j}")
# add adder outputs
ps.append([f"add_{i}_out_{j}" for j in range(aw + 1)])
i += 1
# connect outputs
for i, o in enumerate(ps[0]):
c.add(f"out_{i}", "output", fanin=o)
if not c.fanout("tie0"):
c.remove("tie0")
return c
class VerilogCircuitGraphTransformer(Transformer):
"""
A lark.Transformer that transforms a parsed verilog netlist into a
circuitgraph.Circuit.
"""
def __init__(self,
text,
blackboxes,
warnings=False,
error_on_warning=False):
"""
Initializes a new transformer.
Parameters
----------
text: str
The netlist that the transformer will be used on, used for
error messages.
blackboxes: list of circuitgraph.BlackBox
The blackboxes present in the netlist that will be parsed.
warnings: bool
If True, warnings about unused nets will be printed.
error_on_warning: bool
If True, unused nets will cause raise `VerilogParsingWarning`
exceptions.
"""
self.c = Circuit()
self.text = text
self.blackboxes = blackboxes
self.warnings = warnings
self.error_on_warning = error_on_warning
self.tie0 = self.c.add("tie0", "0")
self.tie1 = self.c.add("tie1", "1")
self.io = set()
self.inputs = set()
self.outputs = set()
self.wires = set()
# Helper functions
def add_node(self, n, node_type, fanin=[], fanout=[], uid=False):
"""So that nodes are of type `str`, not `lark.Token`"""
if type(fanin) not in [list, set]:
fanin = [fanin]
if type(fanout) not in [list, set]:
fanout = [fanout]
fanin = [str(i) for i in fanin]
fanout = [str(i) for i in fanout]
node_type = str(node_type)
for i in fanout + fanin:
if i not in self.c:
self.c.add(i, "buf")
return self.c.add(
str(n),
node_type,
fanin=fanin,
fanout=fanout,
uid=uid,
)
def add_blackbox(self, blackbox, name, connections=dict()):
formatted_connections = dict()
for key in connections:
formatted_connections[str(key)] = str(connections[key])
if str(connections[key]) not in self.c:
self.c.add(str(connections[key]), "buf")
self.c.add_blackbox(blackbox, str(name), formatted_connections)
def warn(self, message):
if self.error_on_warning:
raise VerilogParsingWarning(message)
else:
print(f"Warning: {message}")
def check_for_warnings(self):
for wire in self.wires:
if wire not in self.c.nodes():
self.warn(f"{wire} declared as wire but isn't connected.")
for n in self.c.nodes():
if self.c.type(n) not in ["output", "bb_input"
] and not self.c.fanout(n):
self.warn(f"{n} doesn't drive any nets.")
elif self.c.type(n) not in [
"input",
"0",
"1",
"bb_output",
] and not self.c.fanin(n):
self.warn(f"{n} doesn't have any drivers.")
# 1. Source text
def start(self, description):
return description
def module(self, module_name_and_list_of_ports_and_module_items):
self.c.name = str(module_name_and_list_of_ports_and_module_items[0])
# Check if ports list matches with inputs and outputs
if not self.inputs <= self.io:
i = (self.inputs - self.io).pop()
raise VerilogParsingError(
f"{i} declared as output but not in port list", i, self.text)
if not self.outputs <= self.io:
o = (self.outputs - self.io).pop()
raise VerilogParsingError(
f"{o} declared as output but not in port list", o, self.text)
if not self.io <= (self.inputs | self.outputs):
v = (self.io - (self.inputs | self.outputs)).pop()
raise VerilogParsingError(
f"{v} in port list but was not declared as input or output",
v,
self.text,
)
# Relabel outputs using drivers
for o in self.outputs:
o = str(o)
if self.c.fanin(o):
o_driver = f"{o}_driver"
while o_driver in self.c.nodes():
o_driver += "_0"
self.c.relabel({o: o_driver})
self.add_node(o, "output")
self.c.connect(o_driver, o)
# Remove tie0, tie1 if not used
if not self.c.fanout(self.tie0):
self.c.remove(self.tie0)
if not self.c.fanout(self.tie1):
self.c.remove(self.tie1)
# Check for warnings
if self.warnings:
self.check_for_warnings()
return self.c
def list_of_ports(self, ports):
for port in ports:
self.io.add(port)
# 2. Declarations
def input_declaration(self, list_of_variables):
[list_of_variables] = list_of_variables
self.inputs.update(list_of_variables)
for variable in list_of_variables:
self.add_node(variable, "input")
def output_declaration(self, list_of_variables):
[list_of_variables] = list_of_variables
self.outputs.update(list_of_variables)
for variable in list_of_variables:
self.add_node(variable, "output")
def net_declaration(self, list_of_variables):
[list_of_variables] = list_of_variables
self.wires.update(list_of_variables)
def list_of_variables(self, identifiers):
return identifiers
# 3. Primitive Instances
# These are merged with module isntantiations
# 4. Module Instantiations
def module_instantiation(self, name_of_module_and_module_instances):
name_of_module = name_of_module_and_module_instances[0]
module_instances = name_of_module_and_module_instances[1:]
# Check if this is a primitive gate
if name_of_module in addable_types:
for name, ports in module_instances:
if isinstance(ports, dict):
raise VerilogParsingError(
"Primitive gates cannot use named port connections",
name,
self.text,
)
self.add_node(ports[0],
name_of_module,
fanin=[p for p in ports[1:]])
# Check if this is a GTECH gate
elif name_of_module.startswith("GTECH_") and name_of_module.split("_")[
-1].rstrip(digits).lower() in addable_types + ["zero", "one"]:
gate = name_of_module.split("_")[-1].rstrip(digits).lower()
if gate == "zero":
gate = "0"
if gate == "one":
gate = "1"
for name, connections in module_instances:
if not isinstance(connections, dict):
raise VerilogParsingError(
"GTECH gates must use named port connections",
name,
self.text,
)
output = connections["Z"]
inputs = set(connections.values()) - {output}
self.add_node(output, gate, fanin=inputs)
# Otherwise, try to parse as blackbox
else:
try:
bb = {i.name: i for i in self.blackboxes}[name_of_module]
except KeyError:
raise VerilogParsingError(
f"Blackbox {name_of_module} not in list of defined blackboxes.",
name_of_module,
self.text,
)
for name, connections in module_instances:
if not isinstance(connections, dict):
raise VerilogParsingError(
"Blackbox instantiations must use named port connections",
name,
self.text,
)
for output in bb.outputs():
if output in connections:
self.add_node(connections[output], "buf")
self.add_blackbox(bb, name, connections)
def module_instance(self,
name_of_instance_and_list_of_module_connecetions):
(
name_of_instance,
list_of_module_connecetions,
) = name_of_instance_and_list_of_module_connecetions
return (name_of_instance, list_of_module_connecetions)
def list_of_module_connections(self, module_port_connections):
if isinstance(module_port_connections[0], dict):
d = dict()
for m in module_port_connections:
d.update(m)
return d
else:
return module_port_connections
def module_port_connection(self, expression):
return expression[0]
def named_port_connection(self, identifier_and_expression):
[identifier, expression] = identifier_and_expression
return {identifier: expression}
# 5. Behavioral Statements
def assignment(self, lvalue_and_expression):
[lvalue, expression] = lvalue_and_expression
if lvalue not in [self.tie0, self.tie1]:
self.add_node(lvalue, "buf", fanin=expression)
# 6. Specify Section
# 7. Expressions
def expression(self, s):
return s[0]
def constant_zero(self, value):
return self.tie0
def constant_one(self, value):
return self.tie1
def not_gate(self, items):
io = "_".join(items)
return self.add_node(f"not_{io}", "not", fanin=items[0], uid=True)
def xor_gate(self, items):
io = "_".join(items)
return self.add_node(f"xor_{io}",
"xor",
fanin=[items[0], items[1]],
uid=True)
def xnor_gate(self, items):
io = "_".join(items)
return self.add_node(f"xnor_{io}",
"xnor",
fanin=[items[0], items[1]],
uid=True)
def and_gate(self, items):
io = "_".join(items)
return self.add_node(f"and_{io}",
"and",
fanin=[items[0], items[1]],
uid=True)
def or_gate(self, items):
io = "_".join(items)
return self.add_node(f"or_{io}",
"or",
fanin=[items[0], items[1]],
uid=True)
def ternary(self, items):
io = "_".join(items)
n = self.add_node(f"mux_n_{io}", "not", fanin=items[0], uid=True)
a0 = self.add_node(f"mux_a0_{io}",
"and",
fanin=[n, items[2]],
uid=True)
a1 = self.add_node(f"mux_a1_{io}",
"and",
fanin=[items[0], items[1]],
uid=True)
return self.add_node(f"mux_o_{io}", "or", fanin=[a0, a1], uid=True)
def circuit_to_verilog(c):
"""
Generates a str of Verilog code from a `CircuitGraph`.
Parameters
----------
c: Circuit
the circuit to turn into Verilog.
Returns
-------
str
Verilog code.
"""
c = Circuit(graph=c.graph.copy(),
name=c.name,
blackboxes=c.blackboxes.copy())
# sanitize escaped nets
for node in c.nodes():
if node.startswith("\\"):
c.relabel({node: node + " "})
inputs = list(c.inputs())
outputs = list(c.outputs())
insts = []
wires = []
# remove outputs drivers
driver_mapping = dict()
for output in outputs:
if len(c.fanin(output)) > 1:
raise ValueError(f"Output {output} has multiple drivers.")
elif len(c.fanin(output)) == 1:
driver = c.fanin(output).pop()
if c.type(driver) in ["input", "1", "0"]:
driver = c.add(f"{output}_driver",
type="buf",
fanin=driver,
uid=True)
driver_mapping[driver] = output
c.remove(c.outputs())
c.relabel(driver_mapping)
# blackboxes
output_map = {}
for name, bb in c.blackboxes.items():
io = []
for n in bb.inputs():
driver = c.fanin(f"{name}.{n}").pop()
io += [f".{n}({driver})"]
for n in bb.outputs():
w = c.uid(f"{name}_{n}_load")
wires.append(w)
output_map[f"{name}.{n}"] = w
io += [f".{n}({w})"]
io_def = ", ".join(io)
insts.append(f"{bb.name} {name} ({io_def})")
# gates
for n in c.nodes():
if c.type(n) in [
"xor", "xnor", "buf", "not", "nor", "or", "and", "nand"
]:
fanin = [
output_map[f] if f in output_map else f for f in c.fanin(n)
]
fanin = ", ".join(fanin)
insts.append(f"{c.type(n)} g_{len(insts)} " f"({n}, {fanin})")
wires.append(n)
elif c.type(n) in ["0", "1"]:
insts.append(f"assign {n} = 1'b{c.type(n)}")
wires.append(n)
elif c.type(n) in ["input", "output", "bb_input", "bb_output"]:
pass
else:
raise ValueError(f"unknown gate type: {c.type(n)}")
verilog = f"module {c.name} ("
verilog += ", ".join(inputs + outputs)
verilog += ");\n"
verilog += "".join(f" input {inp};\n" for inp in inputs)
verilog += "\n"
verilog += "".join(f" output {out};\n" for out in outputs)
verilog += "\n"
verilog += "".join(f" wire {wire};\n" for wire in wires)
verilog += "\n"
verilog += "".join(f" {inst};\n" for inst in insts)
verilog += "endmodule\n"
return verilog