amaranth/amaranth/sim/pysim.py

473 lines
17 KiB
Python

from contextlib import contextmanager
import itertools
import re
from ..hdl import *
from ..hdl._repr import *
from ..hdl._mem import MemoryInstance, MemoryIdentity
from ..hdl._ast import SignalDict, Slice, Operator
from ._base import *
from ._pyrtl import _FragmentCompiler
from ._pycoro import PyCoroProcess
from ._pyclock import PyClockProcess
__all__ = ["PySimEngine"]
class _VCDWriter:
@staticmethod
def decode_to_vcd(format, value):
return format.format(value).expandtabs().replace(" ", "_")
@staticmethod
def eval_field(field, signal, value):
if isinstance(field, Signal):
assert field is signal
return value
elif isinstance(field, Const):
return field.value
elif isinstance(field, Slice):
sub = _VCDWriter.eval_field(field.value, signal, value)
return (sub >> field.start) & ((1 << (field.stop - field.start)) - 1)
elif isinstance(field, Operator) and field.operator in ('s', 'u'):
sub = _VCDWriter.eval_field(field.operands[0], signal, value)
return Const(sub, field.shape()).value
else:
raise NotImplementedError
def __init__(self, fragment, *, vcd_file, gtkw_file=None, traces=()):
# Although pyvcd is a mandatory dependency, be resilient and import it as needed, so that
# the simulator is still usable if it's not installed for some reason.
import vcd, vcd.gtkw
self.close_vcd = False
self.close_gtkw = False
if isinstance(vcd_file, str):
vcd_file = open(vcd_file, "w")
self.close_vcd = True
if isinstance(gtkw_file, str):
gtkw_file = open(gtkw_file, "w")
self.close_gtkw = True
self.vcd_signal_vars = SignalDict()
self.vcd_memory_vars = {}
self.vcd_file = vcd_file
self.vcd_writer = vcd_file and vcd.VCDWriter(self.vcd_file,
timescale="1 ps", comment="Generated by Amaranth")
self.gtkw_signal_names = SignalDict()
self.gtkw_memory_names = {}
self.gtkw_file = gtkw_file
self.gtkw_save = gtkw_file and vcd.gtkw.GTKWSave(self.gtkw_file)
self.traces = []
signal_names = SignalDict()
memories = {}
for subfragment, subfragment_name in \
fragment._assign_names_to_fragments(hierarchy=("bench", "top",)).items():
for signal, signal_name in subfragment._assign_names_to_signals().items():
if signal not in signal_names:
signal_names[signal] = set()
signal_names[signal].add((*subfragment_name, signal_name))
if isinstance(subfragment, MemoryInstance):
memories[subfragment._identity] = (subfragment, subfragment_name)
trace_names = SignalDict()
assigned_names = set()
for trace in traces:
if isinstance(trace, ValueLike):
trace = Value.cast(trace)
for trace_signal in trace._rhs_signals():
if trace_signal not in signal_names:
if trace_signal.name not in assigned_names:
name = trace_signal.name
else:
name = f"{trace_signal.name}${len(assigned_names)}"
assert name not in assigned_names
trace_names[trace_signal] = {("bench", name)}
assigned_names.add(name)
self.traces.append(trace_signal)
elif hasattr(trace, "_identity") and isinstance(trace._identity, MemoryIdentity):
if not trace._identity in memories:
raise ValueError(f"{trace!r} is a memory not part of the elaborated design")
self.traces.append(trace._identity)
else:
raise TypeError(f"{trace!r} is not a traceable object")
if self.vcd_writer is None:
return
for signal, names in itertools.chain(signal_names.items(), trace_names.items()):
self.vcd_signal_vars[signal] = []
self.gtkw_signal_names[signal] = []
for repr in signal._value_repr:
var_init = self.eval_field(repr.value, signal, signal.init)
if isinstance(repr.format, FormatInt):
var_type = "wire"
var_size = repr.value.shape().width
else:
var_type = "string"
var_size = 1
var_init = self.decode_to_vcd(repr.format, var_init)
vcd_var = None
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))
field_name = var_name
for item in repr.path:
if isinstance(item, int):
field_name += f"[{item}]"
else:
field_name += f".{item}"
if repr.path:
field_name = "\\" + field_name
if vcd_var is None:
vcd_var = self.vcd_writer.register_var(
scope=var_scope, name=field_name,
var_type=var_type, size=var_size, init=var_init)
if var_size > 1:
suffix = f"[{var_size - 1}:0]"
else:
suffix = ""
self.gtkw_signal_names[signal].append(".".join((*var_scope, field_name)) + suffix)
else:
self.vcd_writer.register_alias(
scope=var_scope, name=field_name,
var=vcd_var)
self.vcd_signal_vars[signal].append((vcd_var, repr))
for memory, memory_name in memories.values():
self.vcd_memory_vars[memory._identity] = vcd_vars = []
self.gtkw_memory_names[memory._identity] = gtkw_names = []
if memory._width > 1:
suffix = f"[{memory._width - 1}:0]"
else:
suffix = ""
for idx, init in enumerate(memory._init):
field_name = "\\" + memory_name[-1] + f"[{idx}]"
var_scope = memory_name[:-1]
vcd_var = self.vcd_writer.register_var(
scope=var_scope, name=field_name,
var_type="wire", size=memory._width, init=init,
)
vcd_vars.append(vcd_var)
gtkw_field_name = field_name + suffix
gtkw_name = ".".join((*var_scope, gtkw_field_name))
gtkw_names.append(gtkw_name)
def update_signal(self, timestamp, signal, value):
for (vcd_var, repr) in self.vcd_signal_vars.get(signal, ()):
var_value = self.eval_field(repr.value, signal, value)
if not isinstance(repr.format, FormatInt):
var_value = self.decode_to_vcd(repr.format, var_value)
self.vcd_writer.change(vcd_var, timestamp, var_value)
def update_memory(self, timestamp, memory, addr, value):
vcd_var = self.vcd_memory_vars[memory._identity][addr]
self.vcd_writer.change(vcd_var, timestamp, 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 isinstance(signal, Signal):
for name in self.gtkw_signal_names[signal]:
self.gtkw_save.trace(name)
elif isinstance(signal, MemoryIdentity):
for name in self.gtkw_memory_names[signal]:
self.gtkw_save.trace(name)
else:
assert False # :nocov:
if self.close_vcd:
self.vcd_file.close()
if self.close_gtkw:
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 = {}
self.curr = self.next = signal.init
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 _PyMemoryChange:
__slots__ = ("state", "addr")
def __init__(self, state, addr):
self.state = state
self.addr = addr
class _PyMemoryState(BaseMemoryState):
__slots__ = ("memory", "data", "write_queue", "waiters", "pending")
def __init__(self, memory, pending):
self.memory = memory
self.pending = pending
self.waiters = {}
self.reset()
def reset(self):
self.data = list(self.memory._init)
self.write_queue = []
def commit(self):
if not self.write_queue:
return False
for addr, value, mask in self.write_queue:
curr = self.data[addr]
value = (value & mask) | (curr & ~mask)
self.data[addr] = value
self.write_queue.clear()
awoken_any = False
for process in self.waiters:
process.runnable = awoken_any = True
return awoken_any
def read(self, addr):
if addr not in range(self.memory._depth):
return 0
return self.data[addr]
def write(self, addr, value, mask=None):
if addr not in range(self.memory._depth):
return
if mask == 0:
return
if mask is None:
mask = (1 << self.memory._width) - 1
self.write_queue.append((addr, value, mask))
self.pending.add(self)
class _PySimulation(BaseSimulation):
def __init__(self):
self.timeline = _Timeline()
self.signals = SignalDict()
self.memories = {}
self.slots = []
self.pending = set()
def add_memory(self, fragment):
self.memories[fragment._identity] = len(self.slots)
self.slots.append(_PyMemoryState(fragment, self.pending))
def reset(self):
self.timeline.reset()
for signal, index in self.signals.items():
state = self.slots[index]
assert isinstance(state, _PySignalState)
state.curr = state.next = signal.init
for index in self.memories.values():
state = self.slots[index]
assert isinstance(state, _PyMemoryState)
state.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 add_memory_trigger(self, process, identity):
index = self.memories[identity]
self.slots[index].waiters[process] = None
def remove_memory_trigger(self, process, identity):
index = self.memories[identity]
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 state in self.pending:
if changed is not None:
if isinstance(state, _PyMemoryState):
for addr, _value, _mask in state.write_queue:
changed.add(_PyMemoryChange(state, addr))
elif isinstance(state, _PySignalState):
changed.add(state)
else:
assert False # :nocov:
if state.commit():
converged = False
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 change in changed:
if isinstance(change, _PySignalState):
signal_state = change
vcd_writer.update_signal(self._timeline.now,
signal_state.signal, signal_state.curr)
elif isinstance(change, _PyMemoryChange):
vcd_writer.update_memory(self._timeline.now, change.state.memory,
change.addr, change.state.data[change.addr])
else:
assert False # :nocov:
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)