src/add/fpcommon/pack.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, Elaboratable
   6 from nmigen.cli import main, verilog
   7
   8 from fpbase import FPNumOut
   9 from fpbase import FPState
  10 from fpcommon.roundz import FPRoundData
  11 from singlepipe import Object
  12
  13
  14 class FPPackData(Object):
  15
  16     def __init__(self, width, id_wid):
  17         Object.__init__(self)
  18         self.z = Signal(width, reset_less=True)
  19         self.mid = Signal(id_wid, reset_less=True)
  20
  21
  22 class FPPackMod(Elaboratable):
  23
  24     def __init__(self, width, id_wid):
  25         self.width = width
  26         self.id_wid = id_wid
  27         self.i = self.ispec()
  28         self.o = self.ospec()
  29
  30     def ispec(self):
  31         return FPRoundData(self.width, self.id_wid)
  32
  33     def ospec(self):
  34         return FPPackData(self.width, self.id_wid)
  35
  36     def process(self, i):
  37         return self.o
  38
  39     def setup(self, m, in_z):
  40         """ links module to inputs and outputs
  41         """
  42         m.submodules.pack = self
  43         m.d.comb += self.i.eq(in_z)
  44
  45     def elaborate(self, platform):
  46         m = Module()
  47         z = FPNumOut(self.width, False)
  48         m.submodules.pack_in_z = self.i.z
  49         m.submodules.pack_out_z = z
  50         m.d.comb += self.o.mid.eq(self.i.mid)
  51         with m.If(~self.i.out_do_z):
  52             with m.If(self.i.z.is_overflowed):
  53                 m.d.comb += z.inf(self.i.z.s)
  54             with m.Else():
  55                 m.d.comb += z.create(self.i.z.s, self.i.z.e, self.i.z.m)
  56         with m.Else():
  57             m.d.comb += z.v.eq(self.i.oz)
  58         m.d.comb += self.o.z.eq(z.v)
  59         return m
  60
  61
  62 class FPPack(FPState):
  63
  64     def __init__(self, width, id_wid):
  65         FPState.__init__(self, "pack")
  66         self.mod = FPPackMod(width)
  67         self.out_z = self.ospec()
  68
  69     def ispec(self):
  70         return self.mod.ispec()
  71
  72     def ospec(self):
  73         return self.mod.ospec()
  74
  75     def setup(self, m, in_z):
  76         """ links module to inputs and outputs
  77         """
  78         self.mod.setup(m, in_z)
  79
  80         m.d.sync += self.out_z.v.eq(self.mod.out_z.v)
  81         m.d.sync += self.out_z.mid.eq(self.mod.o.mid)
  82
  83     def action(self, m):
  84         m.next = "pack_put_z"