from migen.fhdl.std import * from migen.fhdl.tools import value_bits_sign from migen.fhdl.structure import _Operator def bitreverse(s): length, signed = value_bits_sign(s) l = [s[i] for i in reversed(range(length))] return Cat(*l) def optree(op, operands, lb=None, ub=None, default=None): if lb is None: lb = 0 if ub is None: ub = len(operands) l = ub - lb if l == 0: if default is None: raise AttributeError else: return default elif l == 1: return operands[lb] else: s = lb + l//2 return _Operator(op, [optree(op, operands, lb, s, default), optree(op, operands, s, ub, default)]) def split(v, *counts): r = [] offset = 0 for n in counts: r.append(v[offset:offset+n]) offset += n return tuple(r) def displacer(signal, shift, output, n=None, reverse=False): if n is None: n = 2**flen(shift) w = flen(signal) if reverse: r = reversed(range(n)) else: r = range(n) l = [Replicate(shift == i, w) & signal for i in r] return output.eq(Cat(*l)) def chooser(signal, shift, output, n=None, reverse=False): if n is None: n = 2**flen(shift) w = flen(output) cases = {} for i in range(n): if reverse: s = n - i - 1 else: s = i cases[i] = [output.eq(signal[s*w:(s+1)*w])] return Case(shift, cases).makedefault() def timeline(trigger, events): lastevent = max([e[0] for e in events]) counter = Signal(max=lastevent+1) counterlogic = If(counter != 0, counter.eq(counter + 1) ).Elif(trigger, counter.eq(1) ) # insert counter reset if it doesn't naturally overflow # (test if lastevent+1 is a power of 2) if (lastevent & (lastevent + 1)) != 0: counterlogic = If(counter == lastevent, counter.eq(0) ).Else( counterlogic ) def get_cond(e): if e[0] == 0: return trigger & (counter == 0) else: return counter == e[0] sync = [If(get_cond(e), *e[1]) for e in events] sync.append(counterlogic) return sync