DpgenNand2mask

• Name : DpgenNand2mask - Programmable Mask Macro-Generator
• Synopsys :

  Generate ( 'DpgenNand2mask', modelname
           , param = { 'nbit'       : n
                     , 'const'      : constVal
                     , 'physical'   : True
                     , 'behavioral' : True                   
                     }
           )
  

• Description : Generates a n bits conditionnal NAND mask named modelname.
• Terminal Names :
  • cmd : mask control ( 1 bit )
  • i0 : input ( n bits )
  • nq : output ( n bits )
  • vdd : power
  • vss : ground
• Parameters : Parameters are given in the map param.
  • nbit (mandatory) : Defines the size of the generator
  • const (mandatory) : Defines the constant (string beginning with 0b, 0x or 0o functions of the basis)
  • physical (optional, default value : False) : In order to generate a layout
  • behavioral (optional, default value : False) : In order to generate a behavior
• How it works :
  • If the cmd signal is set to zero, the mask is NOT applied, so the whole operator behaves like an inverter.
  • If the cmd signal is set to one, the mask is applied, the output is the complemented result of the input value ANDed with the mask (suplied by constVal).
  • The constant constVal is given to the macro-generator call, therefore the value cannot be changed afterward : it's hard wired in the operator.
  • A common error is to give a real constant for the constVal argument. Be aware that it is a character string.
• Behavior :

  nq <= WITH cmd SELECT not(i0)              WHEN '0',
                        not(i0 and constVal) WHEN '1';
  

• Example :

  from stratus import *
  
  class inst_nand2mask ( Model ) :
  
    def Interface ( self ) :
      self.i   = SignalIn  (   "i", 32 )
      self.cmd = SignalIn  ( "cmd",  1 )
      self.o   = SignalOut (   "o", 32 )
  
      self.vdd = VddIn ( "vdd" )
      self.vss = VssIn ( "vss" )
      
    def Netlist ( self ) :
      Generate ( 'DpgenNand2mask', 'nand2mask_0x0000ffff'
               , param = { 'nbit'     : 32
                         , 'const'    : "0x0000FFFF"
                         , 'physical' : True
                         }
               )      
      self.I = Inst ( 'nand2mask_0x0000ffff', 'inst'
                    , map = { 'i0'  : self.i
                            , 'cmd' : self.cmd
                            , 'nq'  : self.o
                            , 'vdd' : self.vdd
                            , 'vss' : self.vss
                            }
                    )
      
    def Layout ( self ) :
      Place ( self.I, NOSYM, Ref(0, 0) )