amaranth/amaranth/sim/pysim.py
2024-06-10 10:34:32 +00:00

715 lines
27 KiB
Python

from contextlib import contextmanager
import itertools
import re
import os.path
import enum as py_enum
from ..hdl import *
from ..hdl._mem import MemoryInstance
from ..hdl._ast import SignalDict
from ..lib import data, wiring
from ._base import *
from ._async import *
from ._pyeval import eval_format, eval_value, eval_assign
from ._pyrtl import _FragmentCompiler
from ._pyclock import PyClockProcess
__all__ = ["PySimEngine"]
class _VCDWriter:
@staticmethod
def decode_to_vcd(format, value):
return format.format(value).expandtabs().replace(" ", "_")
def __init__(self, state, design, *, vcd_file, gtkw_file=None, traces=(), fs_per_delta=0):
self.state = state
self.fs_per_delta = fs_per_delta
# 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 fs", 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 = traces
signal_names = SignalDict()
memories = {}
for fragment, fragment_info in design.fragments.items():
fragment_name = ("bench", *fragment_info.name)
for signal, signal_name in fragment_info.signal_names.items():
if signal not in signal_names:
signal_names[signal] = set()
signal_names[signal].add((*fragment_name, signal_name))
if isinstance(fragment, MemoryInstance):
memories[fragment._data] = fragment_name
trace_names = SignalDict()
assigned_names = set()
def traverse_traces(traces):
if isinstance(traces, ValueLike):
trace = Value.cast(traces)
if isinstance(trace, MemoryData._Row):
memory = trace._memory
if not memory in memories:
if memory.name not in assigned_names:
name = memory.name
else:
name = f"{memory.name}${len(assigned_names)}"
assert name not in assigned_names
memories[memory] = ("bench", name)
assigned_names.add(name)
else:
for trace_signal in trace._rhs_signals():
if trace_signal not in signal_names:
if trace_signal.name not in assigned_names:
name = trace_signal.name
else:
name = f"{trace_signal.name}${len(assigned_names)}"
assert name not in assigned_names
trace_names[trace_signal] = {("bench", name)}
assigned_names.add(name)
elif isinstance(traces, MemoryData):
if not traces in memories:
if traces.name not in assigned_names:
name = traces.name
else:
name = f"{traces.name}${len(assigned_names)}"
assert name not in assigned_names
memories[traces] = ("bench", name)
assigned_names.add(name)
elif hasattr(traces, "signature") and isinstance(traces.signature, wiring.Signature):
for name in traces.signature.members:
traverse_traces(getattr(traces, name))
elif isinstance(traces, list) or isinstance(traces, tuple):
for trace in traces:
traverse_traces(trace)
elif isinstance(traces, dict):
for trace in traces.values():
traverse_traces(trace)
else:
raise TypeError(f"{traces!r} is not a traceable object")
traverse_traces(traces)
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] = []
def add_var(path, var_type, var_size, var_init, value):
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 path:
if isinstance(item, int):
field_name += f"[{item}]"
else:
field_name += f".{item}"
if 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, value))
def add_wire_var(path, value):
add_var(path, "wire", len(value), eval_value(self.state, value), value)
def add_format_var(path, fmt):
add_var(path, "string", 1, eval_format(self.state, fmt), fmt)
def add_format(path, fmt):
if isinstance(fmt, Format.Struct):
add_wire_var(path, fmt._value)
for name, subfmt in fmt._fields.items():
add_format(path + (name,), subfmt)
elif isinstance(fmt, Format.Array):
add_wire_var(path, fmt._value)
for idx, subfmt in enumerate(fmt._fields):
add_format(path + (idx,), subfmt)
elif (isinstance(fmt, Format) and
len(fmt._chunks) == 1 and
isinstance(fmt._chunks[0], tuple) and
fmt._chunks[0][1] == ""):
add_wire_var(path, fmt._chunks[0][0])
else:
add_format_var(path, fmt)
if signal._decoder is not None and not isinstance(signal._decoder, py_enum.EnumMeta):
add_var((), "string", 1, signal._decoder(signal._init), signal._decoder)
else:
add_format((), signal._format)
for memory, memory_name in memories.items():
self.vcd_memory_vars[memory] = vcd_vars = []
self.gtkw_memory_names[memory] = gtkw_names = []
for idx, row in enumerate(memory):
row_vcd_vars = []
row_gtkw_names = []
var_scope = memory_name[:-1]
def add_mem_var(path, var_type, var_size, var_init, value):
field_name = "\\" + memory_name[-1] + f"[{idx}]"
for item in path:
if isinstance(item, int):
field_name += f"[{item}]"
else:
field_name += f".{item}"
row_vcd_vars.append((self.vcd_writer.register_var(
scope=var_scope, name=field_name, var_type=var_type,
size=var_size, init=var_init
), value))
if var_size > 1:
suffix = f"[{var_size - 1}:0]"
else:
suffix = ""
row_gtkw_names.append(".".join((*var_scope, field_name)) + suffix)
def add_mem_wire_var(path, value):
add_mem_var(path, "wire", len(value), eval_value(self.state, value), value)
def add_mem_format_var(path, fmt):
add_mem_var(path, "string", 1, eval_format(self.state, fmt), fmt)
def add_mem_format(path, fmt):
if isinstance(fmt, Format.Struct):
add_mem_wire_var(path, fmt._value)
for name, subfmt in fmt._fields.items():
add_mem_format(path + (name,), subfmt)
elif isinstance(fmt, Format.Array):
add_mem_wire_var(path, fmt._value)
for idx, subfmt in enumerate(fmt._fields):
add_mem_format(path + (idx,), subfmt)
elif (isinstance(fmt, Format) and
len(fmt._chunks) == 1 and
isinstance(fmt._chunks[0], tuple) and
fmt._chunks[0][1] == ""):
add_mem_wire_var(path, fmt._chunks[0][0])
else:
add_mem_format_var(path, fmt)
if isinstance(memory._shape, ShapeCastable):
fmt = memory._shape.format(memory._shape(row), "")
add_mem_format((), fmt)
else:
add_mem_wire_var((), row)
vcd_vars.append(row_vcd_vars)
gtkw_names.append(row_gtkw_names)
def update_signal(self, timestamp, signal):
for (vcd_var, repr) in self.vcd_signal_vars.get(signal, ()):
if isinstance(repr, Value):
var_value = eval_value(self.state, repr)
elif isinstance(repr, (Format, Format.Enum)):
var_value = eval_format(self.state, repr)
else:
# decoder
var_value = repr(eval_value(self.state, signal))
self.vcd_writer.change(vcd_var, timestamp, var_value)
def update_memory(self, timestamp, memory, addr):
if memory not in self.vcd_memory_vars:
return
for vcd_var, repr in self.vcd_memory_vars[memory][addr]:
if isinstance(repr, Value):
var_value = eval_value(self.state, repr)
else:
var_value = eval_format(self.state, repr)
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")
def traverse_traces(traces):
if isinstance(traces, Signal):
for name in self.gtkw_signal_names[traces]:
self.gtkw_save.trace(name)
elif isinstance(traces, data.View):
with self.gtkw_save.group("view"):
trace = Value.cast(traces)
for trace_signal in trace._rhs_signals():
for name in self.gtkw_signal_names[trace_signal]:
self.gtkw_save.trace(name)
elif isinstance(traces, ValueLike):
traverse_traces(Value.cast(traces))
elif isinstance(traces, MemoryData):
for row_names in self.gtkw_memory_names[traces]:
for name in row_names:
self.gtkw_save.trace(name)
elif isinstance(traces, MemoryData._Row):
for name in self.gtkw_memory_names[traces._memory][traces._index]:
self.gtkw_save.trace(name)
elif hasattr(traces, "signature") and isinstance(traces.signature, wiring.Signature):
with self.gtkw_save.group("interface"):
for _, _, member in traces.signature.flatten(traces):
traverse_traces(member)
elif isinstance(traces, list) or isinstance(traces, tuple):
for trace in traces:
traverse_traces(trace)
elif isinstance(traces, dict):
for name, trace in traces.items():
with self.gtkw_save.group(name):
traverse_traces(trace)
else:
assert False # :nocov:
traverse_traces(self.traces)
if self.close_vcd:
self.vcd_file.close()
if self.close_gtkw:
self.gtkw_file.close()
class _PyTimeline:
def __init__(self):
self.now = 0
self.wakers = {}
def reset(self):
self.now = 0
self.wakers.clear()
def set_waker(self, interval, waker):
self.wakers[waker] = self.now + interval
def advance(self):
nearest_wakers = set()
nearest_deadline = None
for waker, deadline in self.wakers.items():
if nearest_deadline is None or deadline <= nearest_deadline:
assert deadline >= self.now
if nearest_deadline is not None and deadline < nearest_deadline:
nearest_wakers.clear()
nearest_wakers.add(waker)
nearest_deadline = deadline
if not nearest_wakers:
return False
for waker in nearest_wakers:
waker()
del self.wakers[waker]
self.now = nearest_deadline
return True
def _run_wakers(wakers: list, *args):
# Python doesn't have `.retain()` :(
index = 0
for waker in wakers:
if waker(*args):
wakers[index] = waker
index += 1
del wakers[index:]
class _PySignalState(BaseSignalState):
__slots__ = ("signal", "is_comb", "curr", "next", "wakers", "pending")
def __init__(self, signal, pending):
self.signal = signal
self.is_comb = False
self.pending = pending
self.wakers = list()
self.reset()
def reset(self):
self.curr = self.next = self.signal.init
def add_waker(self, waker):
assert waker not in self.wakers
self.wakers.append(waker)
def update(self, value):
if self.next != value:
self.next = value
self.pending.add(self)
def commit(self):
if self.curr == self.next:
return False
_run_wakers(self.wakers, self.curr, self.next)
self.curr = self.next
return True
class _PyMemoryChange:
__slots__ = ("state", "addr")
def __init__(self, state, addr):
self.state = state
self.addr = addr
class _PyMemoryState(BaseMemoryState):
__slots__ = ("memory", "data", "write_queue", "wakers", "pending")
def __init__(self, memory, pending):
self.memory = memory
self.pending = pending
self.wakers = list()
self.reset()
def reset(self):
self.data = list(self.memory._init._raw)
self.write_queue = {}
def add_waker(self, waker):
assert waker not in self.wakers
self.wakers.append(waker)
def read(self, addr):
if addr in range(self.memory.depth):
return self.data[addr]
return 0
def write(self, addr, value, mask=None):
if addr in range(self.memory.depth):
if addr not in self.write_queue:
self.write_queue[addr] = self.data[addr]
if mask is not None:
value = (value & mask) | (self.write_queue[addr] & ~mask)
self.write_queue[addr] = value
self.pending.add(self)
def commit(self):
assert self.write_queue # `commit()` is only called if `self` is pending
_run_wakers(self.wakers)
changed = False
for addr, value in self.write_queue.items():
if self.data[addr] != value:
self.data[addr] = value
changed = True
self.write_queue.clear()
return changed
class _PyEngineState(BaseEngineState):
def __init__(self):
self.timeline = _PyTimeline()
self.signals = SignalDict()
self.memories = dict()
self.slots = list()
self.pending = set()
def reset(self):
self.timeline.reset()
for state in self.slots:
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 get_memory(self, memory):
try:
return self.memories[memory]
except KeyError:
index = len(self.slots)
self.slots.append(_PyMemoryState(memory, self.pending))
self.memories[memory] = index
return index
def set_delay_waker(self, interval, waker):
self.timeline.set_waker(interval, waker)
def add_signal_waker(self, signal, waker):
self.slots[self.get_signal(signal)].add_waker(waker)
def add_memory_waker(self, memory, waker):
self.slots[self.get_memory(memory)].add_waker(waker)
def commit(self, changed=None):
converged = True
for state in self.pending:
if changed is not None:
if isinstance(state, _PyMemoryState):
for addr 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 _PyTriggerState:
def __init__(self, engine, combination, pending, *, oneshot):
self._engine = engine
self._combination = combination
self._active = pending
self._oneshot = oneshot
self._result = None
self._broken = False
self._triggers_hit = set()
self._delay_wakers = dict()
for trigger in combination._triggers:
if isinstance(trigger, SampleTrigger):
pass # does not cause a wakeup
elif isinstance(trigger, ChangedTrigger):
self.add_changed_waker(trigger)
elif isinstance(trigger, EdgeTrigger):
self.add_edge_waker(trigger)
elif isinstance(trigger, DelayTrigger):
self.add_delay_waker(trigger)
else:
assert False # :nocov:
def add_changed_waker(self, trigger):
def waker(curr, next):
if self._broken:
return False
self.activate()
return not self._oneshot
self._engine.state.add_signal_waker(trigger.signal, waker)
def add_edge_waker(self, trigger):
def waker(curr, next):
if self._broken:
return False
curr_bit = (curr >> trigger.bit) & 1
next_bit = (next >> trigger.bit) & 1
if curr_bit == next_bit or next_bit != trigger.polarity:
return True # wait until next edge
self._triggers_hit.add(trigger)
self.activate()
return not self._oneshot
self._engine.state.add_signal_waker(trigger.signal, waker)
def add_delay_waker(self, trigger):
def waker():
if self._broken:
return
self._triggers_hit.add(trigger)
self.activate()
self._engine.state.set_delay_waker(trigger.interval_fs, waker)
self._delay_wakers[waker] = trigger.interval_fs
def activate(self):
if self._combination._process.waits_on is self:
self._active.add(self)
else:
self._broken = True
def run(self):
result = []
for trigger in self._combination._triggers:
if isinstance(trigger, (SampleTrigger, ChangedTrigger)):
value = self._engine.get_value(trigger.value)
if isinstance(trigger.shape, ShapeCastable):
result.append(trigger.shape.from_bits(value))
else:
result.append(value)
elif isinstance(trigger, (EdgeTrigger, DelayTrigger)):
result.append(trigger in self._triggers_hit)
else:
assert False # :nocov:
self._result = tuple(result)
self._combination._process.runnable = True
self._combination._process.waits_on = None
self._triggers_hit.clear()
for waker, interval_fs in self._delay_wakers.items():
self._engine.state.set_delay_waker(interval_fs, waker)
def __await__(self):
self._result = None
if self._broken:
raise BrokenTrigger
yield self
if self._broken:
raise BrokenTrigger
return self._result
class PySimEngine(BaseEngine):
def __init__(self, design):
self._design = design
self._state = _PyEngineState()
self._processes = _FragmentCompiler(self._state)(self._design.fragment)
self._testbenches = []
self._delta_cycles = 0
self._vcd_writers = []
self._active_triggers = set()
@property
def state(self) -> BaseEngineState:
return self._state
@property
def now(self):
return self._state.timeline.now
def _now_plus_deltas(self, fs_per_delta):
return self._state.timeline.now + self._delta_cycles * fs_per_delta
def reset(self):
self._state.reset()
for process in self._processes:
process.reset()
for testbench in self._testbenches:
testbench.reset()
def add_clock_process(self, clock, *, phase, period):
self._processes.add(PyClockProcess(self._state, clock,
phase=phase, period=period))
def add_async_process(self, simulator, process):
self._processes.add(AsyncProcess(self._design, self, process,
testbench=False, background=True))
def add_async_testbench(self, simulator, process, *, background):
self._testbenches.append(AsyncProcess(self._design, self, process,
testbench=True, background=background))
def add_trigger_combination(self, combination, *, oneshot):
return _PyTriggerState(self, combination, self._active_triggers, oneshot=oneshot)
def get_value(self, expr):
return eval_value(self._state, Value.cast(expr))
def set_value(self, expr, value):
assert isinstance(value, int)
return eval_assign(self._state, Value.cast(expr), value)
def step_design(self):
# Performs the three phases of a delta cycle in a loop:
converged = False
while not converged:
changed = set() if self._vcd_writers else None
# 1a. trigger: run every active trigger, sampling values and waking up processes;
for trigger_state in self._active_triggers:
trigger_state.run()
self._active_triggers.clear()
# 1b. eval: run every runnable processes once, queueing signal changes;
for process in self._processes:
if process.runnable:
process.runnable = False
process.run()
if type(process) is AsyncProcess and process.waits_on is not None:
assert type(process.waits_on) is _PyTriggerState, \
"Async processes may only await simulation triggers"
# 2. commit: apply queued signal changes, activating any awaited triggers.
converged = self._state.commit(changed)
for vcd_writer in self._vcd_writers:
now_plus_deltas = self._now_plus_deltas(vcd_writer.fs_per_delta)
for change in changed:
if type(change) is _PySignalState:
signal_state = change
vcd_writer.update_signal(now_plus_deltas,
signal_state.signal)
elif type(change) is _PyMemoryChange:
vcd_writer.update_memory(now_plus_deltas, change.state.memory,
change.addr)
else:
assert False # :nocov:
self._delta_cycles += 1
def advance(self):
# Run triggers and processes until the simulation converges.
self.step_design()
# Run testbenches that have been awoken in `step_design()` by active triggers.
converged = False
while not converged:
converged = True
# Schedule testbenches in a deterministic order (the one in which they were added).
for testbench in self._testbenches:
if testbench.runnable:
testbench.runnable = False
testbench.run()
if type(testbench) is AsyncProcess and testbench.waits_on is not None:
assert type(testbench.waits_on) is _PyTriggerState, \
"Async testbenches may only await simulation triggers"
converged = False
# Now that the simulation has converged for the current time, advance the timeline.
self._state.timeline.advance()
# Check if the simulation has any critical processes or testbenches.
for runnables in (self._processes, self._testbenches):
for runnable in runnables:
if runnable.critical:
return True
return False
@contextmanager
def write_vcd(self, *, vcd_file, gtkw_file, traces, fs_per_delta):
vcd_writer = _VCDWriter(self._state, self._design,
vcd_file=vcd_file, gtkw_file=gtkw_file, traces=traces, fs_per_delta=fs_per_delta)
try:
self._vcd_writers.append(vcd_writer)
yield
finally:
vcd_writer.close(self._now_plus_deltas(vcd_writer.fs_per_delta))
self._vcd_writers.remove(vcd_writer)