Pydgin: a (Py)thon (D)SL for (G)enerating (In)struction set simulators.

Pydgin provides a collection of classes and functions which act as an embedded architectural description language (embedded-ADL) for concisely describing the behavior of instruction set simulators (ISS). An ISS described in Pydgin can be directly executed in a Python interpreter for rapid prototyping and debugging, or alternatively can be used to automatically generate a performant, JIT-optimizing C executable more suitable for application development.

Automatic generation of JIT-enabled ISS from Pydgin is enabled by the RPython Translation Toolchain, an open-source tool used by developers of the PyPy JIT-optimizing Python interpreter. [1]

An ISS described in Pydgin implements an interpretive simulator which can be directly executed in a Python interpreter for rapid prototyping and debugging. However, Pydgin ISS can also be automatically translated into a C executable implementing a JIT-enabled interpretive simulator, providing a high-performance implementation suitable for application development. Generated Pydgin executables provide significant performance benefits in two ways. First, the compiled C implementation enables much more efficient execution of instruction-by-instruction interpretive simulation than the original Python implementation. Second, the generated executable provides a just-in-time optimizer, which h

The following directories Pydgin libraries and simulator implementations for executing ELF binaries compiled with a cross-compiler.

• pydgin: Library for describing instruction set simulators (ISS).
• arm: Pydgin ISS for executing ARMv5 binaries.
• parc: Pydgin ISS for executing PARC binaries.

The following directories contain experimental interpreters for executing textual files. They serve no purpose other than to learn more about the capabilities of the RPython translation toolchain.

• parc_interp: An interpreter for the complete PARC ISA.
• asm_toy_2: A toy interpreter for (less) simple PARC assembly files.
• asm_toy_1: A toy interpreter for (very) simple PARC assembly files.
• bf: A simple interpreter for a toy language.

Please see the README files in each subdirectory for more information.

• http://www.wilfred.me.uk/blog/2014/05/24/r-python-for-fun-and-profit/
• http://morepypy.blogspot.com/2011/04/tutorial-writing-interpreter-with-pypy.html
• http://morepypy.blogspot.co.uk/2011/04/tutorial-part-2-adding-jit.html
• https://bitbucket.org/brownan/pypy-tutorial/
• http://pie-interpreter.blogspot.com/2012/12/how-to-make-new-interpreter-with-pypy.html
• http://indefinitestudies.org/2010/02/08/creating-a-toy-virtual-machine-with-pypy

• http://morepypy.blogspot.com/2011/03/controlling-tracing-of-interpreter-with.html
• http://morepypy.blogspot.com/2011/03/controlling-tracing-of-interpreter-with_15.html
• http://morepypy.blogspot.com/2011/03/controlling-tracing-of-interpreter-with_21.html
• http://morepypy.blogspot.com/2011/03/controlling-tracing-of-interpreter-with_26.html
• http://bitbucket.org/pypy/extradoc/raw/extradoc/talk/icooolps2011/bolz-hints.pdf
• http://pypy.readthedocs.org/en/latest/jit/pyjitpl5.html
• http://morepypy.blogspot.com/2010/06/jit-for-regular-expression-matching.html
• https://github.com/samgiles/naulang/blob/master/naulang/compiler/parser.py
• https://github.com/alex/rply

Fails::

int( some_str, base=16 )

Translates, but fails during execution::

int( some_str, 16 )

Works::

rpython.rlib.rarithmetic.string_to_int( some_str, base=16 )

Fails::

line.split()

Works::

line.split(' ', 3)

Fails::

with open( filename, 'rb' ) as file_obj: ...

Works::

file_obj = open( filename, 'rb ) file_obj.close()

Fails::

string = string.ljust( nchars, '0' )

Works::

string = '0'*( nchars - len(string) ) + string

Fails::

my_array[start_idx:]

Works::

assert start_idx >= 0 my_array[start_idx:]

Fails::

assert obj.attr >= 0 my_array[obj.attr:]

Works::

start_idx = obj.attr assert start_idx >= 0 my_array[start_idx:]

Fails::

section_name = start.partition('0')[0]

Works::

section_name = start.split( '0', 1 )[0]

Fails::

if my_str != None: do_something()

Works::

if my_str != '': do_something()

Fails::

raise Exception( 'Error %08x!' % my_value )

Works::

raise Exception( 'Error %x!' % my_value )