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         self.ctx = FPPipeContext(pspec)
  14         self.muxid = self.ctx.muxid
  15
  16     def __iter__(self):
  17         yield self.z0
  18         yield from self.ctx
  19
  20     def eq(self, i):
  21         return [self.z0.eq(i.z0), self.ctx.eq(i.ctx)]
  22
  23
  24 class CordicOutputData:
  25
  26     def __init__(self, pspec, e_extra=False):
  27         width = pspec.width
  28         self.x = Signal(width)
  29         self.y = Signal(width)
  30         self.ctx = FPPipeContext(pspec)
  31         self.muxid = self.ctx.muxid
  32
  33     def __iter__(self):
  34         yield self.x
  35         yield self.y
  36         yield from self.ctx
  37
  38     def eq(self, i):
  39         return [self.x.eq(i.x), self.y.eq(i.y),
  40                 self.ctx.eq(i.ctx)]
  41
  42
  43 class CordicData:
  44
  45     def __init__(self, pspec):
  46
  47         M = pspec.M
  48         ZMAX = pspec.ZMAX
  49         self.x = Signal(range(-M, M+1), name="x")   # operand a
  50         self.y = Signal(range(-M, M+1), name="y")   # operand b
  51         self.z = Signal(range(-ZMAX, ZMAX), name="z")     # denormed result
  52         self.ctx = FPPipeContext(pspec)
  53         self.muxid = self.ctx.muxid
  54
  55     def __iter__(self):
  56         yield self.x
  57         yield self.y
  58         yield self.z
  59         yield from self.ctx
  60
  61     def eq(self, i):
  62         ret = [self.z.eq(i.z), self.x.eq(i.x), self.y.eq(i.y),
  63                self.ctx.eq(i.ctx)]
  64         return ret
  65
  66
  67 class CordicPipeSpec:
  68     def __init__(self, fracbits, rounds_per_stage):
  69         self.fracbits = fracbits
  70         # Number of cordic operations per pipeline stage
  71         self.rounds_per_stage = rounds_per_stage
  72         self.M = (1 << fracbits)
  73         self.ZMAX = int(round(self.M * math.pi/2))
  74         zm = Const(-self.ZMAX)
  75         self.iterations = zm.width - 1
  76
  77         self.pipekls = SimpleHandshakeRedir
  78         self.stage = None