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
   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
  12
  13 class FPPackData:
  14
  15     def __init__(self, width, id_wid):
  16         self.z = Signal(width, reset_less=True)
  17         self.mid = Signal(id_wid, reset_less=True)
  18
  19     def __iter__(self):
  20         yield self.z
  21         yield self.mid
  22
  23     def eq(self, i):
  24         return [self.z.eq(i.z), self.mid.eq(i.mid)]
  25
  26     def ports(self):
  27         return list(self)
  28
  29
  30 class FPPackMod:
  31
  32     def __init__(self, width, id_wid):
  33         self.width = width
  34         self.id_wid = id_wid
  35         self.i = self.ispec()
  36         self.o = self.ospec()
  37
  38     def ispec(self):
  39         return FPRoundData(self.width, self.id_wid)
  40
  41     def ospec(self):
  42         return FPPackData(self.width, self.id_wid)
  43
  44     def process(self, i):
  45         return self.o
  46
  47     def setup(self, m, in_z):
  48         """ links module to inputs and outputs
  49         """
  50         m.submodules.pack = self
  51         m.d.comb += self.i.eq(in_z)
  52
  53     def elaborate(self, platform):
  54         m = Module()
  55         z = FPNumOut(self.width, False)
  56         m.submodules.pack_in_z = self.i.z
  57         m.submodules.pack_out_z = z
  58         m.d.comb += self.o.mid.eq(self.i.mid)
  59         with m.If(~self.i.out_do_z):
  60             with m.If(self.i.z.is_overflowed):
  61                 m.d.comb += z.inf(self.i.z.s)
  62             with m.Else():
  63                 m.d.comb += z.create(self.i.z.s, self.i.z.e, self.i.z.m)
  64         with m.Else():
  65             m.d.comb += z.v.eq(self.i.oz)
  66         m.d.comb += self.o.z.eq(z.v)
  67         return m
  68
  69
  70 class FPPack(FPState):
  71
  72     def __init__(self, width, id_wid):
  73         FPState.__init__(self, "pack")
  74         self.mod = FPPackMod(width)
  75         self.out_z = self.ospec()
  76
  77     def ispec(self):
  78         return self.mod.ispec()
  79
  80     def ospec(self):
  81         return self.mod.ospec()
  82
  83     def setup(self, m, in_z):
  84         """ links module to inputs and outputs
  85         """
  86         self.mod.setup(m, in_z)
  87
  88         m.d.sync += self.out_z.v.eq(self.mod.out_z.v)
  89         m.d.sync += self.out_z.mid.eq(self.mod.o.mid)
  90
  91     def action(self, m):
  92         m.next = "pack_put_z"