DILL (Digital Logic in LOTOS)

See the download page to obtain this program


DILL (Digital Logic in LOTOS) is an approach for specifying digital logic circuits and translating them to LOTOS. Circuits are described using the DILL language that builds designs from their constituent components. See the DILL web page for details of publications.


As an example, consider a two-input and gate with one input inverted (i.e. not(x) and y). The DILL description required to define this component is as follows:




    `NotAnd2 [Ip1, Ip2, Op]',
    `hide NotIp1 in
      Inverter [Ip1, NotIp1]
      And2 [NotIp1, Ip2, Op]

The divert macro prevents output while the macro library is being processed. The include macro brings in the DILL library. The circuit macro defines the LOTOS functionality of the whole circuit and the LOTOS behaviour expression that comprises it. Declarations from the library are included by giving the component name and the suffix _Decl (declaration). m4 requires macro parameters containing commas to be given in single quotes.

It is strongly recommended to use GNU m4 with DILL since, among other things, it allows a search path to be given for included files. In some other m4 is used, the source DILL file must be in the same directory as the DILL library files.

Suppose that DILL files are given the suffix .dill and that the DILL library is installed in /usr/local/lib/dill. C-shell users could then define the following convenient alias:

  alias dill 'm4 -I /usr/local/lib/dill \!:1.dill >! \!:1.lot'

This will make it possible to translate the DILL file myfile.dill to LOTOS with a command like:

  dill myfile

DILL Library and Examples

The DILL library contains the following files:
dill.m4the base DILL module
dill_adder_bb.m4adders (black-box)
dill_bitarray.m4bit arrays
dill_coder.m4encoders and decoders
dill_coder_wb.m4encoders and decoders (white box)
dill_comparator_bb_wb.m4counters (black-box, white box)
dill_counter_bb.m4counters (black-box)
dill_flipflop_bb.m4flip-flops (black-box)
dill_gate.m41/2/3/4/8-input logic gates
dill_gate_tri.m41/2/3/4/8-input logic gates (tri-state)
dill_latch_bb_wb.m4latches (black-box, white box)
dill_memory.m4memory devices
dill_memory_bb.m4memories (black-box)
dill_multi.m4multiple components and wires
dill_parity.m4parity devices
dill_parity_bb.m4parity devices (black-box)
dill_plexer_bb_wb.m4(de)multiplexers (black-box, white box)
dill_register_bb.m4registers (black-box)

The following example files are included in subdirectory ex of the distribution:

and2.*two-input "and"
bits.*bit operations
cpu_beha.*abstract behavioural description of simple CPU
cpu_gate.*gate-level description of simple CPU
cpu_struc.*intermediate structural description of simple CPU
decoder2.*two-input decoder
gate1.*all one-input logic gates
gate2.*all two-input logic gates
gates.*sample logic gates
keycon.*matrix keyboard controller
multis.*multiple components and wires
notand.*"and" gate with one input inverted
rslatch.*RS latch
*.dillDILL macro input files
*.simdefinitions for hippo simulator
*.lotgenerated LOTOS files

Using DILL is reasonably straightforward (provided one knows how to formulate and compose LOTOS processes). However, anyone who wishes to study or modify the library should be warned that the macros are very intricate!


DILL is free software, distributed under the GNU Public License Version 2. You may re-distribute this software provided you preserve this README file. The contents of this package may be used freely for non-commercial purposes provided this README file and copyright notices are retained. Copyright remains with the authors. No warranties are given as to the accuracy or suitability of this package.

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Last Update: 15th July 2006
URL: https://www.cs.stir.ac.uk/~kjt/software/lotos/dill.html