src/add/fpadd/addstages.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.denorm import FPSCData
  19 from fpcommon.postcalc import FPAddStage1Data
  20 from fpadd.align import FPAddAlignSingleMod
  21 from fpadd.add0 import (FPAddStage0Data, FPAddStage0Mod, FPAddStage0)
  22 from fpadd.add1 import (FPAddStage1Mod, FPAddStage1)
  23
  24
  25 class FPAddAlignSingleAdd(FPState, UnbufferedPipeline):
  26
  27     def __init__(self, width, id_wid):
  28         FPState.__init__(self, "align")
  29         self.width = width
  30         self.id_wid = id_wid
  31         UnbufferedPipeline.__init__(self, self) # pipeline is its own stage
  32         self.a1o = self.ospec()
  33
  34     def ispec(self):
  35         return FPSCData(self.width, self.id_wid)
  36
  37     def ospec(self):
  38         return FPAddStage1Data(self.width, self.id_wid) # AddStage1 ospec
  39
  40     def setup(self, m, i):
  41         """ links module to inputs and outputs
  42         """
  43
  44         # chain AddAlignSingle, AddStage0 and AddStage1
  45         mod = FPAddAlignSingleMod(self.width, self.id_wid)
  46         a0mod = FPAddStage0Mod(self.width, self.id_wid)
  47         a1mod = FPAddStage1Mod(self.width, self.id_wid)
  48
  49         chain = StageChain([mod, a0mod, a1mod])
  50         chain.setup(m, i)
  51
  52         self.o = a1mod.o
  53
  54     def process(self, i):
  55         return self.o
  56
  57     def action(self, m):
  58         m.d.sync += self.a1o.eq(self.process(None))
  59         m.next = "normalise_1"
  60
  61