src/nmutil/mask.py

   1 from nmigen import Module, Signal, Elaboratable
   2 from nmigen.utils import log2_int
   3
   4 def masked(m_out, m_in, mask):
   5     return (m_out & ~mask) | (m_in & mask)
   6
   7
   8 class Mask(Elaboratable):
   9     def __init__(self, sz):
  10         self.sz = sz
  11         self.shift = Signal(log2_int(sz, False)+1)
  12         self.mask = Signal(sz)
  13
  14     def elaborate(self, platform):
  15         m = Module()
  16
  17         for i in range(self.sz):
  18             with m.If(self.shift > i):
  19                 m.d.comb += self.mask[i].eq(1)
  20
  21         return m
  22