litex/migen/fhdl/tools.py

203 lines
5.5 KiB
Python

import collections
from migen.fhdl.structure import *
from migen.fhdl.structure import _Operator, _Slice, _Assign, _ArrayProxy
from migen.fhdl.visit import NodeVisitor, NodeTransformer
def flat_iteration(l):
for element in l:
if isinstance(element, collections.Iterable):
for element2 in flat_iteration(element):
yield element2
else:
yield element
class _SignalLister(NodeVisitor):
def __init__(self):
self.output_list = set()
def visit_Signal(self, node):
self.output_list.add(node)
class _TargetLister(NodeVisitor):
def __init__(self):
self.output_list = set()
self.target_context = False
def visit_Signal(self, node):
if self.target_context:
self.output_list.add(node)
def visit_Assign(self, node):
self.target_context = True
self.visit(node.l)
self.target_context = False
def list_signals(node):
lister = _SignalLister()
lister.visit(node)
return lister.output_list
def list_targets(node):
lister = _TargetLister()
lister.visit(node)
return lister.output_list
def group_by_targets(sl):
groups = []
for statement in flat_iteration(sl):
targets = list_targets(statement)
processed = False
for g in groups:
if not targets.isdisjoint(g[0]):
g[0].update(targets)
g[1].append(statement)
processed = True
break
if not processed:
groups.append((targets, [statement]))
return groups
def list_special_ios(f, ins, outs, inouts):
r = set()
for special in f.specials:
r |= special.list_ios(ins, outs, inouts)
return r
def list_clock_domains(f):
r = set(f.sync.keys())
for special in f.specials:
r |= special.get_clock_domains()
for cd in f.clock_domains:
r.add(cd.name)
return r
def is_variable(node):
if isinstance(node, Signal):
return node.variable
elif isinstance(node, _Slice):
return is_variable(node.value)
elif isinstance(node, Cat):
arevars = list(map(is_variable, node.l))
r = arevars[0]
for x in arevars:
if x != r:
raise TypeError
return r
else:
raise TypeError
def insert_reset(rst, sl):
targets = list_targets(sl)
resetcode = [t.eq(t.reset) for t in sorted(targets, key=lambda x: x.huid)]
return [If(rst, *resetcode).Else(*sl)]
def value_bits_sign(v):
if isinstance(v, bool):
return 1, False
elif isinstance(v, int):
return bits_for(v), v < 0
elif isinstance(v, Signal):
return v.nbits, v.signed
elif isinstance(v, _Operator):
obs = list(map(value_bits_sign, v.operands))
if v.op == "+" or v.op == "-":
if not obs[0][1] and not obs[1][1]:
# both operands unsigned
return max(obs[0][0], obs[1][0]) + 1, False
elif obs[0][1] and obs[1][1]:
# both operands signed
return max(obs[0][0], obs[1][0]) + 1, True
elif not obs[0][1] and obs[1][1]:
# first operand unsigned (add sign bit), second operand signed
return max(obs[0][0] + 1, obs[1][0]) + 1, True
else:
# first signed, second operand unsigned (add sign bit)
return max(obs[0][0], obs[1][0] + 1) + 1, True
elif v.op == "*":
if not obs[0][1] and not obs[1][1]:
# both operands unsigned
return obs[0][0] + obs[1][0]
elif obs[0][1] and obs[1][1]:
# both operands signed
return obs[0][0] + obs[1][0] - 1
else:
# one operand signed, the other unsigned (add sign bit)
return obs[0][0] + obs[1][0] + 1 - 1
elif v.op == "<<<":
if obs[1][1]:
extra = 2**(obs[1][0] - 1) - 1
else:
extra = 2**obs[1][0] - 1
return obs[0][0] + extra, obs[0][1]
elif v.op == ">>>":
if obs[1][1]:
extra = 2**(obs[1][0] - 1)
else:
extra = 0
return obs[0][0] + extra, obs[0][1]
elif v.op == "&" or v.op == "^" or v.op == "|":
if not obs[0][1] and not obs[1][1]:
# both operands unsigned
return max(obs[0][0], obs[1][0]), False
elif obs[0][1] and obs[1][1]:
# both operands signed
return max(obs[0][0], obs[1][0]), True
elif not obs[0][1] and obs[1][1]:
# first operand unsigned (add sign bit), second operand signed
return max(obs[0][0] + 1, obs[1][0]), True
else:
# first signed, second operand unsigned (add sign bit)
return max(obs[0][0], obs[1][0] + 1), True
elif v.op == "<" or v.op == "<=" or v.op == "==" or v.op == "!=" \
or v.op == ">" or v.op == ">=":
return 1, False
elif v.op == "~":
return obs[0]
else:
raise TypeError
elif isinstance(v, _Slice):
return v.stop - v.start, value_bits_sign(v.value)[1]
elif isinstance(v, Cat):
return sum(value_bits_sign(sv)[0] for sv in v.l), False
elif isinstance(v, Replicate):
return (value_bits_sign(v.v)[0])*v.n, False
elif isinstance(v, _ArrayProxy):
bsc = map(value_bits_sign, v.choices)
return max(bs[0] for bs in bsc), any(bs[1] for bs in bsc)
else:
raise TypeError
class _ArrayLowerer(NodeTransformer):
def __init__(self):
self.comb = []
def visit_Assign(self, node):
if isinstance(node.l, _ArrayProxy):
k = self.visit(node.l.key)
cases = {}
for n, choice in enumerate(node.l.choices):
assign = self.visit_Assign(_Assign(choice, node.r))
cases[n] = [assign]
return Case(k, cases).makedefault()
else:
return NodeTransformer.visit_Assign(self, node)
def visit_ArrayProxy(self, node):
array_muxed = Signal(value_bits_sign(node))
cases = dict((n, _Assign(array_muxed, self.visit(choice)))
for n, choice in enumerate(node.choices))
self.comb.append(Case(self.visit(node.key), cases).makedefault())
return array_muxed
def lower_arrays(f):
al = _ArrayLowerer()
f2 = al.visit(f)
f2.comb += al.comb
return f2
def bitreverse(s):
length, signed = value_bits_sign(s)
l = [s[i] for i in reversed(range(length))]
return Cat(*l)