litex/migen/pytholite/compiler.py

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import inspect
import ast
from migen.fhdl.structure import *
from migen.pytholite import transel
class FinalizeError(Exception):
pass
class _AbstractLoad:
def __init__(self, target, source):
self.target = target
self.source = source
class _Register:
def __init__(self, name, nbits):
self.storage = Signal(BV(nbits), name=name)
self.source_encoding = {}
self.finalized = False
def load(self, source):
if source not in self.source_encoding:
self.source_encoding[source] = len(self.source_encoding) + 1
return _AbstractLoad(self, source)
def finalize(self):
if self.finalized:
raise FinalizeError
self.sel = Signal(BV(bits_for(len(self.source_encoding) + 1)))
self.finalized = True
def get_fragment(self):
if not self.finalized:
raise FinalizeError
# do nothing when sel == 0
cases = [(v, self.storage.eq(k)) for k, v in self.source_encoding.items()]
sync = [Case(self.sel, *cases)]
return Fragment(sync=sync)
class _AnonymousRegister:
def __init__(self, nbits):
self.nbits = nbits
class _CompileVisitor(ast.NodeVisitor):
def __init__(self, symdict, registers):
self.symdict = symdict
self.registers = registers
def visit_Assign(self, node):
value = self.visit(node.value)
if isinstance(value, _AnonymousRegister):
if isinstance(node.targets[0], ast.Name):
name = node.targets[0].id
else:
raise NotImplementedError
value = _Register(name, value.nbits)
self.registers.append(value)
for target in node.targets:
if isinstance(target, ast.Name):
self.symdict[target.id] = value
else:
raise NotImplementedError
def visit_Call(self, node):
if isinstance(node.func, ast.Name):
callee = self.symdict[node.func.id]
else:
raise NotImplementedError
if callee == transel.Register:
if len(node.args) != 1:
raise TypeError("Register() takes exactly 1 argument")
nbits = ast.literal_eval(node.args[0])
return _AnonymousRegister(nbits)
else:
raise NotImplementedError
def make_pytholite(func):
tree = ast.parse(inspect.getsource(func))
symdict = func.__globals__.copy()
registers = []
cv = _CompileVisitor(symdict, registers)
cv.visit(tree)
print(registers)
print(symdict)
#print(ast.dump(tree))