litex/migen/pytholite/compiler.py

169 lines
4.2 KiB
Python

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 _Compiler:
def __init__(self, symdict, registers):
self.symdict = symdict
self.registers = registers
self.targetname = ""
def visit_top(self, node):
if isinstance(node, ast.Module) \
and len(node.body) == 1 \
and isinstance(node.body[0], ast.FunctionDef):
return self.visit_block(node.body[0].body)
else:
raise NotImplementedError
# blocks and statements
def visit_block(self, statements):
r = []
for statement in statements:
if isinstance(statement, ast.Assign):
r += self.visit_assign(statement)
else:
raise NotImplementedError
return r
def visit_assign(self, node):
if isinstance(node.targets[0], ast.Name):
self.targetname = node.targets[0].id
value = self.visit_expr(node.value, True)
self.targetname = ""
if isinstance(value, _Register):
self.registers.append(value)
for target in node.targets:
if isinstance(target, ast.Name):
self.symdict[target.id] = value
else:
raise NotImplementedError
return []
elif isinstance(value, Value):
r = []
for target in node.targets:
if isinstance(target, ast.Attribute) and target.attr == "store":
treg = target.value
if isinstance(treg, ast.Name):
r.append(self.symdict[treg.id].load(value))
else:
raise NotImplementedError
else:
raise NotImplementedError
return r
else:
raise NotImplementedError
# expressions
def visit_expr(self, node, allow_call=False):
if isinstance(node, ast.Call):
if allow_call:
return self.visit_expr_call(node)
else:
raise NotImplementedError
elif isinstance(node, ast.BinOp):
return self.visit_expr_binop(node)
elif isinstance(node, ast.Name):
return self.visit_expr_name(node)
elif isinstance(node, ast.Num):
return self.visit_expr_num(node)
else:
raise NotImplementedError
def visit_expr_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 _Register(self.targetname, nbits)
else:
raise NotImplementedError
def visit_expr_binop(self, node):
left = self.visit_expr(node.left)
right = self.visit_expr(node.right)
if isinstance(node.op, ast.Add):
return left + right
elif isinstance(node.op, ast.Sub):
return left - right
elif isinstance(node.op, ast.Mult):
return left * right
elif isinstance(node.op, ast.LShift):
return left << right
elif isinstance(node.op, ast.RShift):
return left >> right
elif isinstance(node.op, ast.BitOr):
return left | right
elif isinstance(node.op, ast.BitXor):
return left ^ right
elif isinstance(node.op, ast.BitAnd):
return left & right
else:
raise NotImplementedError
def visit_expr_name(self, node):
r = self.symdict[node.id]
if isinstance(r, _Register):
r = r.storage
return r
def visit_expr_num(self, node):
return node.n
def make_pytholite(func):
tree = ast.parse(inspect.getsource(func))
symdict = func.__globals__.copy()
registers = []
c = _Compiler(symdict, registers)
print("compilation result:")
print(c.visit_top(tree))
print("registers:")
print(registers)
#print("symdict:")
#print(symdict)
print("ast:")
print(ast.dump(tree))