amaranth/amaranth/sim/pysim.py
2023-11-14 13:07:21 +00:00

337 lines
11 KiB
Python

from contextlib import contextmanager
import itertools
import re
from vcd import VCDWriter
from vcd.gtkw import GTKWSave
from ..hdl import *
from ..hdl.ast import SignalDict
from ._base import *
from ._pyrtl import _FragmentCompiler
from ._pycoro import PyCoroProcess
from ._pyclock import PyClockProcess
__all__ = ["PySimEngine"]
class _NameExtractor:
def __init__(self):
self.names = SignalDict()
def __call__(self, fragment, *, hierarchy=("bench", "top",)):
def add_signal_name(signal):
hierarchical_signal_name = (*hierarchy, signal.name)
if signal not in self.names:
self.names[signal] = {hierarchical_signal_name}
else:
self.names[signal].add(hierarchical_signal_name)
for domain_name, domain_signals in fragment.drivers.items():
if domain_name is not None:
domain = fragment.domains[domain_name]
add_signal_name(domain.clk)
if domain.rst is not None:
add_signal_name(domain.rst)
for statement in fragment.statements:
for signal in statement._lhs_signals() | statement._rhs_signals():
if not isinstance(signal, (ClockSignal, ResetSignal)):
add_signal_name(signal)
for subfragment_index, (subfragment, subfragment_name) in enumerate(fragment.subfragments):
if subfragment_name is None:
subfragment_name = f"U${subfragment_index}"
self(subfragment, hierarchy=(*hierarchy, subfragment_name))
return self.names
class _VCDWriter:
@staticmethod
def decode_to_vcd(signal, value):
return signal.decoder(value).expandtabs().replace(" ", "_")
def __init__(self, fragment, *, vcd_file, gtkw_file=None, traces=()):
if isinstance(vcd_file, str):
vcd_file = open(vcd_file, "w")
if isinstance(gtkw_file, str):
gtkw_file = open(gtkw_file, "w")
self.vcd_vars = SignalDict()
self.vcd_file = vcd_file
self.vcd_writer = vcd_file and VCDWriter(self.vcd_file,
timescale="1 ps", comment="Generated by Amaranth")
self.gtkw_names = SignalDict()
self.gtkw_file = gtkw_file
self.gtkw_save = gtkw_file and GTKWSave(self.gtkw_file)
self.traces = []
signal_names = _NameExtractor()(fragment)
trace_names = SignalDict()
for trace in traces:
if trace not in signal_names:
trace_names[trace] = {('bench', trace.name)}
self.traces.append(trace)
if self.vcd_writer is None:
return
for signal, names in itertools.chain(signal_names.items(), trace_names.items()):
if signal.decoder:
var_type = "string"
var_size = 1
var_init = self.decode_to_vcd(signal, signal.reset)
else:
var_type = "wire"
var_size = signal.width
var_init = signal.reset
for (*var_scope, var_name) in names:
if re.search(r"[ \t\r\n]", var_name):
raise NameError("Signal '{}.{}' contains a whitespace character"
.format(".".join(var_scope), var_name))
suffix = None
while True:
try:
if suffix is None:
var_name_suffix = var_name
else:
var_name_suffix = f"{var_name}${suffix}"
if signal not in self.vcd_vars:
vcd_var = self.vcd_writer.register_var(
scope=var_scope, name=var_name_suffix,
var_type=var_type, size=var_size, init=var_init)
self.vcd_vars[signal] = vcd_var
else:
self.vcd_writer.register_alias(
scope=var_scope, name=var_name_suffix,
var=self.vcd_vars[signal])
break
except KeyError:
suffix = (suffix or 0) + 1
if signal not in self.gtkw_names:
self.gtkw_names[signal] = (*var_scope, var_name_suffix)
def update(self, timestamp, signal, value):
vcd_var = self.vcd_vars.get(signal)
if vcd_var is None:
return
if signal.decoder:
var_value = self.decode_to_vcd(signal, value)
else:
var_value = value
self.vcd_writer.change(vcd_var, timestamp, var_value)
def close(self, timestamp):
if self.vcd_writer is not None:
self.vcd_writer.close(timestamp)
if self.gtkw_save is not None:
self.gtkw_save.dumpfile(self.vcd_file.name)
self.gtkw_save.dumpfile_size(self.vcd_file.tell())
self.gtkw_save.treeopen("top")
for signal in self.traces:
if len(signal) > 1 and not signal.decoder:
suffix = f"[{len(signal) - 1}:0]"
else:
suffix = ""
self.gtkw_save.trace(".".join(self.gtkw_names[signal]) + suffix)
if self.vcd_file is not None:
self.vcd_file.close()
if self.gtkw_file is not None:
self.gtkw_file.close()
class _Timeline:
def __init__(self):
self.now = 0
self.deadlines = dict()
def reset(self):
self.now = 0
self.deadlines.clear()
def at(self, run_at, process):
assert process not in self.deadlines
self.deadlines[process] = run_at
def delay(self, delay_by, process):
if delay_by is None:
run_at = self.now
else:
run_at = self.now + delay_by
self.at(run_at, process)
def advance(self):
nearest_processes = set()
nearest_deadline = None
for process, deadline in self.deadlines.items():
if deadline is None:
if nearest_deadline is not None:
nearest_processes.clear()
nearest_processes.add(process)
nearest_deadline = self.now
break
elif nearest_deadline is None or deadline <= nearest_deadline:
assert deadline >= self.now
if nearest_deadline is not None and deadline < nearest_deadline:
nearest_processes.clear()
nearest_processes.add(process)
nearest_deadline = deadline
if not nearest_processes:
return False
for process in nearest_processes:
process.runnable = True
del self.deadlines[process]
self.now = nearest_deadline
return True
class _PySignalState(BaseSignalState):
__slots__ = ("signal", "curr", "next", "waiters", "pending")
def __init__(self, signal, pending):
self.signal = signal
self.pending = pending
self.waiters = dict()
self.curr = self.next = signal.reset
def set(self, value):
if self.next == value:
return
self.next = value
self.pending.add(self)
def commit(self):
if self.curr == self.next:
return False
self.curr = self.next
awoken_any = False
for process, trigger in self.waiters.items():
if trigger is None or trigger == self.curr:
process.runnable = awoken_any = True
return awoken_any
class _PySimulation(BaseSimulation):
def __init__(self):
self.timeline = _Timeline()
self.signals = SignalDict()
self.slots = []
self.pending = set()
def reset(self):
self.timeline.reset()
for signal, index in self.signals.items():
self.slots[index].curr = self.slots[index].next = signal.reset
self.pending.clear()
def get_signal(self, signal):
try:
return self.signals[signal]
except KeyError:
index = len(self.slots)
self.slots.append(_PySignalState(signal, self.pending))
self.signals[signal] = index
return index
def add_trigger(self, process, signal, *, trigger=None):
index = self.get_signal(signal)
assert (process not in self.slots[index].waiters or
self.slots[index].waiters[process] == trigger)
self.slots[index].waiters[process] = trigger
def remove_trigger(self, process, signal):
index = self.get_signal(signal)
assert process in self.slots[index].waiters
del self.slots[index].waiters[process]
def wait_interval(self, process, interval):
self.timeline.delay(interval, process)
def commit(self, changed=None):
converged = True
for signal_state in self.pending:
if signal_state.commit():
converged = False
if changed is not None:
changed.update(self.pending)
self.pending.clear()
return converged
class PySimEngine(BaseEngine):
def __init__(self, fragment):
self._state = _PySimulation()
self._timeline = self._state.timeline
self._fragment = fragment
self._processes = _FragmentCompiler(self._state)(self._fragment)
self._vcd_writers = []
def add_coroutine_process(self, process, *, default_cmd):
self._processes.add(PyCoroProcess(self._state, self._fragment.domains, process,
default_cmd=default_cmd))
def add_clock_process(self, clock, *, phase, period):
self._processes.add(PyClockProcess(self._state, clock,
phase=phase, period=period))
def reset(self):
self._state.reset()
for process in self._processes:
process.reset()
def _step(self):
changed = set() if self._vcd_writers else None
# Performs the two phases of a delta cycle in a loop:
converged = False
while not converged:
# 1. eval: run and suspend every non-waiting process once, queueing signal changes
for process in self._processes:
if process.runnable:
process.runnable = False
process.run()
# 2. commit: apply every queued signal change, waking up any waiting processes
converged = self._state.commit(changed)
for vcd_writer in self._vcd_writers:
for signal_state in changed:
vcd_writer.update(self._timeline.now,
signal_state.signal, signal_state.curr)
def advance(self):
self._step()
self._timeline.advance()
return any(not process.passive for process in self._processes)
@property
def now(self):
return self._timeline.now
@contextmanager
def write_vcd(self, *, vcd_file, gtkw_file, traces):
vcd_writer = _VCDWriter(self._fragment,
vcd_file=vcd_file, gtkw_file=gtkw_file, traces=traces)
try:
self._vcd_writers.append(vcd_writer)
yield
finally:
vcd_writer.close(self._timeline.now)
self._vcd_writers.remove(vcd_writer)