src/ieee754/cordic/pipe_data.py

   1 from nmigen import Signal, Const
   2 from nmutil.dynamicpipe import SimpleHandshakeRedir
   3 from ieee754.fpcommon.fpbase import Overflow, FPNumBaseRecord
   4 from ieee754.fpcommon.getop import FPPipeContext
   5 import math
   6
   7
   8 class CordicInitialData:
   9
  10     def __init__(self, pspec):
  11         ZMAX = pspec.ZMAX
  12         self.z0 = Signal(range(-ZMAX, ZMAX), name="z")     # denormed result
  13
  14     def __iter__(self):
  15         yield self.z0
  16
  17     def eq(self, i):
  18         return [self.z0.eq(i.z0)]
  19
  20
  21 class CordicOutputData:
  22
  23     def __init__(self, pspec, e_extra=False):
  24         width = pspec.width
  25         self.x = FPNumBaseRecord(width, False, e_extra, name="x")
  26         self.y = FPNumBaseRecord(width, False, e_extra, name="y")
  27         self.ctx = FPPipeContext(pspec)
  28         self.muxid = self.ctx.muxid
  29
  30     def __iter__(self):
  31         yield from self.x
  32         yield from self.y
  33         yield from self.ctx
  34
  35     def eq(self, i):
  36         return [self.x.eq(i.x), self.y.eq(i.y),
  37                 self.ctx.eq(i.ctx)]
  38
  39
  40 class CordicData:
  41
  42     def __init__(self, pspec):
  43
  44         M = pspec.M
  45         ZMAX = pspec.ZMAX
  46         self.x = Signal(range(-M, M+1), name="x")   # operand a
  47         self.y = Signal(range(-M, M+1), name="y")   # operand b
  48         self.z = Signal(range(-ZMAX, ZMAX), name="z")     # denormed result
  49
  50     def __iter__(self):
  51         yield self.x
  52         yield self.y
  53         yield self.z
  54
  55     def eq(self, i):
  56         ret = [self.z.eq(i.z), self.x.eq(i.x), self.y.eq(i.y)]
  57         return ret
  58
  59
  60 class CordicPipeSpec:
  61     def __init__(self, fracbits, rounds_per_stage):
  62         self.fracbits = fracbits
  63         # Number of cordic operations per pipeline stage
  64         self.rounds_per_stage = rounds_per_stage
  65         self.M = (1 << fracbits)
  66         self.ZMAX = int(round(self.M * math.pi/2))
  67         zm = Const(-self.ZMAX)
  68         self.iterations = zm.width - 1
  69
  70         self.pipekls = SimpleHandshakeRedir
  71         self.stage = None