src/add/concurrentunit.py

   1 # IEEE Floating Point Adder (Single Precision)
   2 # Copyright (C) Jonathan P Dawson 2013
   3 # 2013-12-12
   4
   5 from math import log
   6 from nmigen import Module
   7 from nmigen.cli import main, verilog
   8
   9 from singlepipe import PassThroughStage
  10 from multipipe import CombMuxOutPipe
  11 from multipipe import PriorityCombMuxInPipe
  12
  13 from fpcommon.getop import FPADDBaseData
  14 from fpcommon.denorm import FPSCData
  15 from fpcommon.pack import FPPackData
  16 from fpcommon.normtopack import FPNormToPack
  17 from fpadd.specialcases import FPAddSpecialCasesDeNorm
  18 from fpadd.addstages import FPAddAlignSingleAdd
  19
  20
  21 def num_bits(n):
  22     return int(log(n) / log(2))
  23
  24 class FPADDInMuxPipe(PriorityCombMuxInPipe):
  25     def __init__(self, num_rows, iospecfn):
  26         self.num_rows = num_rows
  27         stage = PassThroughStage(iospecfn)
  28         PriorityCombMuxInPipe.__init__(self, stage, p_len=self.num_rows)
  29
  30
  31 class FPADDMuxOutPipe(CombMuxOutPipe):
  32     def __init__(self, num_rows, iospecfn):
  33         self.num_rows = num_rows
  34         stage = PassThroughStage(iospecfn)
  35         CombMuxOutPipe.__init__(self, stage, n_len=self.num_rows)
  36
  37
  38 class ReservationStations:
  39     """ Reservation-Station pipeline
  40
  41         Input: num_rows - number of input and output Reservation Stations
  42
  43         Requires: the addition of an "alu" object, an i_specfn and an o_specfn
  44
  45         * fan-in on inputs (an array of FPADDBaseData: a,b,mid)
  46         * ALU pipeline
  47         * fan-out on outputs (an array of FPPackData: z,mid)
  48
  49         Fan-in and Fan-out are combinatorial.
  50     """
  51     def __init__(self, num_rows):
  52         self.num_rows = num_rows
  53         self.inpipe = FPADDInMuxPipe(num_rows, self.i_specfn)   # fan-in
  54         self.outpipe = FPADDMuxOutPipe(num_rows, self.o_specfn) # fan-out
  55
  56         self.p = self.inpipe.p  # kinda annoying,
  57         self.n = self.outpipe.n # use pipe in/out as this class in/out
  58         self._ports = self.inpipe.ports() + self.outpipe.ports()
  59
  60     def elaborate(self, platform):
  61         m = Module()
  62         m.submodules.inpipe = self.inpipe
  63         m.submodules.alu = self.alu
  64         m.submodules.outpipe = self.outpipe
  65
  66         m.d.comb += self.inpipe.n.connect_to_next(self.alu.p)
  67         m.d.comb += self.alu.connect_to_next(self.outpipe)
  68
  69         return m
  70
  71     def ports(self):
  72         return self._ports
  73
  74