pytholite/compiler: create FSM

diff --git a/migen/pytholite/compiler.py b/migen/pytholite/compiler.py
index b25524db5f16788d68bdfd475f4a009b542c39d7..b41d0436d108fb0ee3877984a2d6dd1cabd360be 100644 (file)
--- a/migen/pytholite/compiler.py
+++ b/migen/pytholite/compiler.py
@@ -1,7 +1,10 @@
 import inspect
 import ast
+from operator import itemgetter
 
 from migen.fhdl.structure import *
+from migen.fhdl import visit as fhdl
+from migen.corelogic.fsm import FSM
 from migen.pytholite import transel
 
 class FinalizeError(Exception):
@@ -11,6 +14,18 @@ class _AbstractLoad:
        def __init__(self, target, source):
                self.target = target
                self.source = source
+       
+       def lower(self):
+               if not self.target.finalized:
+                       raise FinalizeError
+               return self.target.sel.eq(self.target.source_encoding[self.source])
+
+class _LowerAbstractLoad(fhdl.NodeTransformer):
+       def visit_unknown(self, node):
+               if isinstance(node, _AbstractLoad):
+                       return node.lower()
+               else:
+                       return node
 
 class _Register:
        def __init__(self, name, nbits):
@@ -26,15 +41,16 @@ class _Register:
        def finalize(self):
                if self.finalized:
                        raise FinalizeError
-               self.sel = Signal(BV(bits_for(len(self.source_encoding) + 1)))
+               self.sel = Signal(BV(bits_for(len(self.source_encoding) + 1)), name="pl_regsel")
                self.finalized = True
        
        def get_fragment(self):
                if not self.finalized:
                        raise FinalizeError
                # do nothing when sel == 0
+               items = sorted(self.source_encoding.items(), key=itemgetter(1))
                cases = [(Constant(v, self.sel.bv),
-                       self.storage.eq(k)) for k, v in self.source_encoding.items()]
+                       self.storage.eq(k)) for k, v in items]
                sync = [Case(self.sel, *cases)]
                return Fragment(sync=sync)
 
@@ -153,6 +169,18 @@ class _Compiler:
        def visit_expr_num(self, node):
                return node.n
 
+def _create_fsm(states):
+       stnames = ["S" + str(i) for i in range(len(states))]
+       fsm = FSM(*stnames)
+       for i, state in enumerate(states):
+               if i == len(states) - 1:
+                       actions = []
+               else:
+                       actions = [fsm.next_state(getattr(fsm, stnames[i+1]))]
+               actions += state
+               fsm.act(getattr(fsm, stnames[i]), *actions)
+       return fsm
+
 def make_pytholite(func):
        tree = ast.parse(inspect.getsource(func))
        symdict = func.__globals__.copy()
@@ -163,11 +191,6 @@ def make_pytholite(func):
        print("compilation result:")
        print(states)
        
-       print("registers:")
-       print(registers)
-       #print("symdict:")
-       #print(symdict)
-
        print("ast:")
        print(ast.dump(tree))
 
@@ -175,4 +198,9 @@ def make_pytholite(func):
        for register in registers:
                register.finalize()
                regf += register.get_fragment()
-       return regf
+       
+       fsm = _create_fsm(states)
+       fsmf = _LowerAbstractLoad().visit(fsm.get_fragment())
+       
+       return regf + fsmf
+