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, 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 FPPackData:
  22
  23     def __init__(self, width, id_wid):
  24         self.z = Signal(width, reset_less=True)
  25         self.mid = Signal(id_wid, reset_less=True)
  26
  27     def eq(self, i):
  28         return [self.z.eq(i.z), self.mid.eq(i.mid)]
  29
  30     def ports(self):
  31         return [self.z, self.mid]
  32
  33
  34 class FPPackMod:
  35
  36     def __init__(self, width, id_wid):
  37         self.width = width
  38         self.id_wid = id_wid
  39         self.i = self.ispec()
  40         self.o = self.ospec()
  41
  42     def ispec(self):
  43         return FPRoundData(self.width, self.id_wid)
  44
  45     def ospec(self):
  46         return FPPackData(self.width, self.id_wid)
  47
  48     def process(self, i):
  49         return self.o
  50
  51     def setup(self, m, in_z):
  52         """ links module to inputs and outputs
  53         """
  54         m.submodules.pack = self
  55         m.d.comb += self.i.eq(in_z)
  56
  57     def elaborate(self, platform):
  58         m = Module()
  59         z = FPNumOut(self.width, False)
  60         m.submodules.pack_in_z = self.i.z
  61         m.submodules.pack_out_z = z
  62         m.d.comb += self.o.mid.eq(self.i.mid)
  63         with m.If(~self.i.out_do_z):
  64             with m.If(self.i.z.is_overflowed):
  65                 m.d.comb += z.inf(self.i.z.s)
  66             with m.Else():
  67                 m.d.comb += z.create(self.i.z.s, self.i.z.e, self.i.z.m)
  68         with m.Else():
  69             m.d.comb += z.v.eq(self.i.oz)
  70         m.d.comb += self.o.z.eq(z.v)
  71         return m
  72
  73
  74 class FPPack(FPState):
  75
  76     def __init__(self, width, id_wid):
  77         FPState.__init__(self, "pack")
  78         self.mod = FPPackMod(width)
  79         self.out_z = self.ospec()
  80
  81     def ispec(self):
  82         return self.mod.ispec()
  83
  84     def ospec(self):
  85         return self.mod.ospec()
  86
  87     def setup(self, m, in_z):
  88         """ links module to inputs and outputs
  89         """
  90         self.mod.setup(m, in_z)
  91
  92         m.d.sync += self.out_z.v.eq(self.mod.out_z.v)
  93         m.d.sync += self.out_z.mid.eq(self.mod.o.mid)
  94
  95     def action(self, m):
  96         m.next = "pack_put_z"