src/soc/fu/shift_rot/rotl.py

   1 from nmigen import (Elaboratable, Signal, Module)
   2 import math
   3
   4 class ROTL(Elaboratable):
   5     def __init__(self, width):
   6         self.width = width
   7         self.shiftwidth = math.ceil(math.log2(width))
   8         self.a = Signal(width, reset_less=True)
   9         self.b = Signal(self.shiftwidth, reset_less=True)
  10
  11         self.o = Signal(width, reset_less=True)
  12
  13     def elaborate(self, platform):
  14         m = Module()
  15         comb = m.d.comb
  16
  17         shl = Signal.like(self.a)
  18         shr = Signal.like(self.a)
  19
  20         comb += shl.eq(self.a << self.b)
  21         comb += shr.eq(self.a >> (self.width - self.b))
  22
  23         comb += self.o.eq(shl | shr)
  24         return m