migen/genlib/divider.py

   1 from migen.fhdl.std import *
   2
   3 class Divider(Module):
   4         def __init__(self, w):
   5                 self.start_i = Signal()
   6                 self.dividend_i = Signal(w)
   7                 self.divisor_i = Signal(w)
   8                 self.ready_o = Signal()
   9                 self.quotient_o = Signal(w)
  10                 self.remainder_o = Signal(w)
  11
  12                 ###
  13
  14                 qr = Signal(2*w)
  15                 counter = Signal(max=w+1)
  16                 divisor_r = Signal(w)
  17                 diff = Signal(w+1)
  18
  19                 self.comb += [
  20                         self.quotient_o.eq(qr[:w]),
  21                         self.remainder_o.eq(qr[w:]),
  22                         self.ready_o.eq(counter == 0),
  23                         diff.eq(self.remainder_o - divisor_r)
  24                 ]
  25                 self.sync += [
  26                         If(self.start_i,
  27                                 counter.eq(w),
  28                                 qr.eq(self.dividend_i),
  29                                 divisor_r.eq(self.divisor_i)
  30                         ).Elif(~self.ready_o,
  31                                         If(diff[w],
  32                                                 qr.eq(Cat(0, qr[:2*w-1]))
  33                                         ).Else(
  34                                                 qr.eq(Cat(1, qr[:w-1], diff[:w]))
  35                                         ),
  36                                         counter.eq(counter - 1)
  37                         )
  38                 ]