litex/migen/genlib/misc.py

132 lines
3.1 KiB
Python

import math
from migen.fhdl.std import *
from migen.fhdl.structure import _Operator
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:
if n != 0:
r.append(v[offset:offset+n])
else:
r.append(None)
offset += n
return tuple(r)
def displacer(signal, shift, output, n=None, reverse=False):
if shift is None:
return output.eq(signal)
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 shift is None:
return output.eq(signal)
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 reverse_bytes(signal):
n = math.ceil(flen(signal)/8)
r = []
for i in reversed(range(n)):
r.append(signal[i*8:min((i+1)*8, flen(signal))])
return Cat(iter(r))
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
@ResetInserter()
@CEInserter()
class FlipFlop(Module):
def __init__(self, *args, **kwargs):
self.d = Signal(*args, **kwargs)
self.q = Signal(*args, **kwargs)
self.sync += self.q.eq(self.d)
@ResetInserter()
@CEInserter()
class Counter(Module):
def __init__(self, *args, increment=1, **kwargs):
self.value = Signal(*args, **kwargs)
self.width = flen(self.value)
self.sync += self.value.eq(self.value+increment)
@ResetInserter()
@CEInserter()
class Timeout(Module):
def __init__(self, length):
self.reached = Signal()
###
value = Signal(max=length)
self.sync += If(~self.reached, value.eq(value+1))
self.comb += self.reached.eq(value == (length-1))