208 lines
5.7 KiB
Python
208 lines
5.7 KiB
Python
from migen.fhdl.structure import *
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from migen.fhdl.structure import _Operator, _Slice, _Assign, _ArrayProxy
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from migen.fhdl.visit import NodeVisitor, NodeTransformer
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class _SignalLister(NodeVisitor):
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def __init__(self):
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self.output_list = set()
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def visit_Signal(self, node):
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self.output_list.add(node)
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class _TargetLister(NodeVisitor):
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def __init__(self):
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self.output_list = set()
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self.target_context = False
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def visit_Signal(self, node):
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if self.target_context:
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self.output_list.add(node)
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def visit_Assign(self, node):
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self.target_context = True
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self.visit(node.l)
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self.target_context = False
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def list_signals(node):
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lister = _SignalLister()
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lister.visit(node)
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return lister.output_list
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def list_targets(node):
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lister = _TargetLister()
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lister.visit(node)
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return lister.output_list
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def group_by_targets(sl):
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groups = []
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for statement in sl:
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targets = list_targets(statement)
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processed = False
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for g in groups:
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if not targets.isdisjoint(g[0]):
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g[0].update(targets)
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g[1].append(statement)
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processed = True
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break
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if not processed:
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groups.append((targets, [statement]))
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return groups
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def list_inst_ios(i, ins, outs, inouts):
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if isinstance(i, Fragment):
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return list_inst_ios(i.instances, ins, outs, inouts)
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elif isinstance(i, set):
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if i:
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return set.union(*(list_inst_ios(e, ins, outs, inouts) for e in i))
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else:
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return set()
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else:
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subsets = [list_signals(item.expr) for item in filter(lambda x:
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(ins and isinstance(x, Instance.Input))
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or (outs and isinstance(x, Instance.Output))
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or (inouts and isinstance(x, Instance.InOut)),
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i.items)]
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if subsets:
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return set.union(*subsets)
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else:
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return set()
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def list_mem_ios(m, ins, outs):
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if isinstance(m, Fragment):
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return list_mem_ios(m.memories, ins, outs)
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else:
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s = set()
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def add(*sigs):
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for sig in sigs:
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if sig is not None:
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s.add(sig)
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for x in m:
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for p in x.ports:
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if ins:
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add(p.adr, p.we, p.dat_w, p.re)
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if outs:
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add(p.dat_r)
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return s
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def is_variable(node):
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if isinstance(node, Signal):
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return node.variable
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elif isinstance(node, _Slice):
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return is_variable(node.value)
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elif isinstance(node, Cat):
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arevars = list(map(is_variable, node.l))
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r = arevars[0]
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for x in arevars:
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if x != r:
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raise TypeError
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return r
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else:
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raise TypeError
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def insert_reset(rst, sl):
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targets = list_targets(sl)
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resetcode = [t.eq(t.reset) for t in sorted(targets, key=lambda x: x.huid)]
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return If(rst, *resetcode).Else(*sl)
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def value_bits_sign(v):
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if isinstance(v, bool):
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return 1, False
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elif isinstance(v, int):
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return bits_for(v), v < 0
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elif isinstance(v, Signal):
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return v.nbits, v.signed
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elif isinstance(v, _Operator):
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obs = list(map(value_bits_sign, v.operands))
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if v.op == "+" or v.op == "-":
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if not obs[0][1] and not obs[1][1]:
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# both operands unsigned
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return max(obs[0][0], obs[1][0]) + 1, False
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elif obs[0][1] and obs[1][1]:
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# both operands signed
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return max(obs[0][0], obs[1][0]) + 1, True
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elif not obs[0][1] and obs[1][1]:
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# first operand unsigned (add sign bit), second operand signed
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return max(obs[0][0] + 1, obs[1][0]) + 1, True
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else:
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# first signed, second operand unsigned (add sign bit)
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return max(obs[0][0], obs[1][0] + 1) + 1, True
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elif v.op == "*":
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if not obs[0][1] and not obs[1][1]:
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# both operands unsigned
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return obs[0][0] + obs[1][0]
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elif obs[0][1] and obs[1][1]:
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# both operands signed
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return obs[0][0] + obs[1][0] - 1
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else:
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# one operand signed, the other unsigned (add sign bit)
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return obs[0][0] + obs[1][0] + 1 - 1
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elif v.op == "<<<":
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if obs[1][1]:
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extra = 2**(obs[1][0] - 1) - 1
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else:
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extra = 2**obs[1][0] - 1
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return obs[0][0] + extra, obs[0][1]
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elif v.op == ">>>":
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if obs[1][1]:
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extra = 2**(obs[1][0] - 1)
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else:
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extra = 0
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return obs[0][0] + extra, obs[0][1]
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elif v.op == "&" or v.op == "^" or v.op == "|":
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if not obs[0][1] and not obs[1][1]:
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# both operands unsigned
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return max(obs[0][0], obs[1][0]), False
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elif obs[0][1] and obs[1][1]:
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# both operands signed
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return max(obs[0][0], obs[1][0]), True
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elif not obs[0][1] and obs[1][1]:
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# first operand unsigned (add sign bit), second operand signed
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return max(obs[0][0] + 1, obs[1][0]), True
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else:
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# first signed, second operand unsigned (add sign bit)
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return max(obs[0][0], obs[1][0] + 1), True
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elif v.op == "<" or v.op == "<=" or v.op == "==" or v.op == "!=" \
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or v.op == ">" or v.op == ">=":
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return 1, False
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else:
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raise TypeError
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elif isinstance(v, _Slice):
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return v.stop - v.start, value_bits_sign(v.value)[1]
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elif isinstance(v, Cat):
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return sum(value_bits_sign(sv)[0] for sv in v.l), False
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elif isinstance(v, Replicate):
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return (value_bits_sign(v.v)[0])*v.n, False
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elif isinstance(v, _ArrayProxy):
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bsc = map(value_bits_sign, v.choices)
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return max(bs[0] for bs in bsc), any(bs[1] for bs in bsc)
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else:
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raise TypeError
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class _ArrayLowerer(NodeTransformer):
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def __init__(self):
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self.comb = []
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def visit_Assign(self, node):
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if isinstance(node.l, _ArrayProxy):
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k = self.visit(node.l.key)
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cases = {}
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for n, choice in enumerate(node.l.choices):
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assign = self.visit_Assign(_Assign(choice, node.r))
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cases[n] = [assign]
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return Case(k, cases).makedefault()
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else:
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return super().visit_Assign(node)
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def visit_ArrayProxy(self, node):
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array_muxed = Signal(value_bits_sign(node))
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cases = dict((n, _Assign(array_muxed, self.visit(choice)))
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for n, choice in enumerate(node.choices))
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self.comb.append(Case(self.visit(node.key), cases).makedefault())
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return array_muxed
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def lower_arrays(f):
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al = _ArrayLowerer()
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f2 = al.visit(f)
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f2.comb += al.comb
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return f2
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