amaranth/nmigen/back/pysim.py

import warnings

from ..sim import *


__all__ = ["Settle", "Delay", "Tick", "Passive", "Active", "Simulator"]


# TODO(nmigen-0.4): remove
warnings.warn("instead of nmigen.back.pysim.*, use nmigen.sim.*",
              DeprecationWarning, stacklevel=2)
back.pysim: warn if simulation is not run. This would have prevented 3ea35b85. 2018-12-29 08:02:04 -07:00			`import warnings`
back.pysim: new simulator backend (WIP). 2018-12-13 11:00:05 -07:00
sim: split into base, core, and engines. Before this commit, each simulation engine (which is only pysim at the moment, but also cxxsim soon) was a subclass of SimulatorCore, and every simulation engine module would essentially duplicate the complete structure of a simulator, with code partially shared. This was a really bad idea: it was inconvenient to use, with downstream code having to branch between e.g. PySettle and CxxSettle; it had no well-defined external interface; it had multiple virtually identical entry points; and it had no separation between simulation algorithms and glue code. This commit completely rearranges simulation code. 1. sim._base defines internal simulation interfaces. The clarity of these internal interfaces is important because simulation engines mix and match components to provide a consistent API regardless of the chosen engine. 2. sim.core defines the external simulation interface: the commands and the simulator facade. The facade provides a single entry point and, when possible, validates or lowers user input. It also imports built-in simulation engines by their symbolic name, avoiding eager imports of pyvcd or ctypes. 3. sim.xxxsim (currently, only sim.pysim) defines the simulator implementation: time and state management, process scheduling, and waveform dumping. The new simulator structure has none of the downsides of the old one. See #324. 2020-08-27 04:17:02 -06:00			`from ..sim import *`
back.pysim: new simulator backend (WIP). 2018-12-13 11:00:05 -07:00

back.pysim: extract simulator commands to sim._cmds. NFC. 2020-07-07 23:42:33 -06:00			`__all__ = ["Settle", "Delay", "Tick", "Passive", "Active", "Simulator"]`
back.pysim: redesign the simulator. The redesign introduces no fundamental incompatibilities, but it does involve minor breaking changes: * The simulator commands were moved from hdl.ast to back.pysim (instead of only being reexported from back.pysim). * back.pysim.DeadlineError was removed. Summary of changes: * The new simulator compiles HDL to Python code and is >6x faster. (The old one compiled HDL to lots of Python lambdas.) * The new simulator is a straightforward, rigorous implementation of the Synchronous Reactive Programming paradigm, instead of a pile of ad-hoc code with no particular design driving it. * The new simulator never raises DeadlineError, and there is no limit on the amount of delta cycles. * The new simulator robustly handles multiclock designs. * The new simulator can be reset, such that the compiled design can be reused, which can save significant runtime with large designs. * Generators can no longer be added as processes, since that would break reset(); only generator functions may be. If necessary, they may be added by wrapping them into a generator function; a deprecated fallback does just that. This workaround will raise an exception if the simulator is reset and restarted. * The new simulator does not depend on Python extensions. (The old one required bitarray, which did not provide wheels.) Fixes #28. Fixes #34. Fixes #160. Fixes #161. Fixes #215. Fixes #242. Fixes #262. 2019-11-22 01:32:41 -07:00

back.pysim→sim.pysim; split into more manageable parts. This is necessary to add cxxrtl as an alternate simulation engine. 2020-07-08 06:49:38 -06:00			`# TODO(nmigen-0.4): remove`
sim: split into base, core, and engines. Before this commit, each simulation engine (which is only pysim at the moment, but also cxxsim soon) was a subclass of SimulatorCore, and every simulation engine module would essentially duplicate the complete structure of a simulator, with code partially shared. This was a really bad idea: it was inconvenient to use, with downstream code having to branch between e.g. PySettle and CxxSettle; it had no well-defined external interface; it had multiple virtually identical entry points; and it had no separation between simulation algorithms and glue code. This commit completely rearranges simulation code. 1. sim._base defines internal simulation interfaces. The clarity of these internal interfaces is important because simulation engines mix and match components to provide a consistent API regardless of the chosen engine. 2. sim.core defines the external simulation interface: the commands and the simulator facade. The facade provides a single entry point and, when possible, validates or lowers user input. It also imports built-in simulation engines by their symbolic name, avoiding eager imports of pyvcd or ctypes. 3. sim.xxxsim (currently, only sim.pysim) defines the simulator implementation: time and state management, process scheduling, and waveform dumping. The new simulator structure has none of the downsides of the old one. See #324. 2020-08-27 04:17:02 -06:00			`warnings.warn("instead of nmigen.back.pysim., use nmigen.sim.",`
back.pysim→sim.pysim; split into more manageable parts. This is necessary to add cxxrtl as an alternate simulation engine. 2020-07-08 06:49:38 -06:00			`DeprecationWarning, stacklevel=2)`