src/add/fpcommon/corrections.py

   1 # IEEE Floating Point Adder (Single Precision)
   2 # Copyright (C) Jonathan P Dawson 2013
   3 # 2013-12-12
   4
   5 from nmigen import Module, Signal, Cat, Mux, Array, Const
   6 from nmigen.lib.coding import PriorityEncoder
   7 from nmigen.cli import main, verilog
   8 from math import log
   9
  10 from fpbase import FPNumIn, FPNumOut, FPOp, Overflow, FPBase, FPNumBase
  11 from fpbase import MultiShiftRMerge, Trigger
  12 from singlepipe import (ControlBase, StageChain, UnbufferedPipeline,
  13                         PassThroughStage)
  14 from multipipe import CombMuxOutPipe
  15 from multipipe import PriorityCombMuxInPipe
  16
  17 from fpbase import FPState, FPID
  18 from fpcommon.roundz import FPRoundData
  19
  20
  21 class FPCorrectionsMod:
  22
  23     def __init__(self, width, id_wid):
  24         self.width = width
  25         self.id_wid = id_wid
  26         self.i = self.ispec()
  27         self.out_z = self.ospec()
  28
  29     def ispec(self):
  30         return FPRoundData(self.width, self.id_wid)
  31
  32     def ospec(self):
  33         return FPRoundData(self.width, self.id_wid)
  34
  35     def process(self, i):
  36         return self.out_z
  37
  38     def setup(self, m, i):
  39         """ links module to inputs and outputs
  40         """
  41         m.submodules.corrections = self
  42         m.d.comb += self.i.eq(i)
  43
  44     def elaborate(self, platform):
  45         m = Module()
  46         m.submodules.corr_in_z = self.i.z
  47         m.submodules.corr_out_z = self.out_z.z
  48         m.d.comb += self.out_z.eq(self.i) # copies mid, z, out_do_z
  49         with m.If(~self.i.out_do_z):
  50             with m.If(self.i.z.is_denormalised):
  51                 m.d.comb += self.out_z.z.e.eq(self.i.z.N127)
  52         return m
  53
  54
  55 class FPCorrections(FPState):
  56
  57     def __init__(self, width, id_wid):
  58         FPState.__init__(self, "corrections")
  59         self.mod = FPCorrectionsMod(width)
  60         self.out_z = self.ospec()
  61
  62     def ispec(self):
  63         return self.mod.ispec()
  64
  65     def ospec(self):
  66         return self.mod.ospec()
  67
  68     def setup(self, m, in_z):
  69         """ links module to inputs and outputs
  70         """
  71         self.mod.setup(m, in_z)
  72
  73         m.d.sync += self.out_z.eq(self.mod.out_z)
  74         m.d.sync += self.out_z.mid.eq(self.mod.o.mid)
  75
  76     def action(self, m):
  77         m.next = "pack"
  78
  79