def _printsig(ns, s): if s.signed: n = "signed " else: n = "" if flen(s) > 1: n += "[" + str(flen(s)-1) + ":0] " n += ns.get_name(s) return n
def _printexpr(ns, node):
if isinstance(node, (int, bool)):
return _printintbool(node)
elif isinstance(node, Signal):
return ns.get_name(node), node.signed
elif isinstance(node, _Operator):
arity = len(node.operands)
r1, s1 = _printexpr(ns, node.operands[0])
if arity == 1:
if node.op == "-":
if s1:
r = node.op + r1
else:
r = "-$signed({1'd0, " + r1 + "})"
s = True
else:
r = node.op + r1
s = s1
elif arity == 2:
r2, s2 = _printexpr(ns, node.operands[1])
if node.op in ["+", "-", "*", "&", "^", "|"]:
if s2 and not s1:
r1 = "$signed({1'd0, " + r1 + "})"
if s1 and not s2:
r2 = "$signed({1'd0, " + r2 + "})"
r = r1 + " " + node.op + " " + r2
s = s1 or s2
else:
raise TypeError
return "(" + r + ")", s
elif isinstance(node, _Slice):
# Verilog does not like us slicing non-array signals...
if isinstance(node.value, Signal) \
and flen(node.value) == 1 \
and node.start == 0 and node.stop == 1:
return _printexpr(ns, node.value)
if node.start + 1 == node.stop:
sr = "[" + str(node.start) + "]"
else:
sr = "[" + str(node.stop-1) + ":" + str(node.start) + "]"
r, s = _printexpr(ns, node.value)
return r + sr, s
elif isinstance(node, Cat):
l = [_printexpr(ns, v)[0] for v in reversed(node.l)]
return "{" + ", ".join(l) + "}", False
elif isinstance(node, Replicate):
return "{" + str(node.n) + "{" + _printexpr(ns, node.v)[0] + "}}", False
else:
raise TypeError
def __getitem__(self, key): from migen.fhdl.size import flen if isinstance(key, int): if key < 0: key += flen(self) return _Slice(self, key, key+1) elif isinstance(key, slice): start = key.start or 0 stop = key.stop or flen(self) if start < 0: start += flen(self) if stop < 0: stop += flen(self) if stop > flen(self): stop = flen(self) if key.step != None: raise KeyError return _Slice(self, start, stop) else: raise KeyError