NAME

       asimut - A simulation tool for hardware descriptions

SYNOPSIS

       asimut [options] [root_file] [pattern_file] [result_file]

DESCRIPTION

       asimut  is  a  logical  simulation tool for hardware descriptions. It compiles and loads a
       complete hardware description  written  in  VHDL  (Very  high  speed  integrated  circuits
       Hardware Description Language). The hardware description may be structural (a hierarchy of
       instances) or behavioural.  Only a subset of VHDL is supported. Descriptions that  do  not
       match  this  subset  cause  a  syntax  error  during compilation. See vhdl(5) for detailed
       information about the supported subset of VHDL.

       Once a hardware description is loaded, asimut looks for a simulation  pattern  description
       file.  This  file is to be written in pat format.  The file is compiled, loaded and linked
       with the hardware  description.  Then,  the  simulation  is  started.  When  patterns  are
       processed, a result file in pat format is produced.

       If  a save action has been requested in the pattern description file (see pat (5)), asimut
       creates also a save file representing the state of the  description  at  the  end  of  the
       simulation  of  the last pattern. The save file is named root_file.sav, where root_file is
       the name of the description.

       The save file can be used in a later simulation sequence to initialize the  state  of  the
       (same)  hardware  description before the simulation begins.  Using this mechanism, a large
       sequence of patterns can be breaked onto several small sequences,  each  one  initializing
       the hardware description with the save file resulted from the previous sequence.

       asimut reads several parameters from the environment variables :

       MBK_CATA_LIB        list  of  directories  containing description and pattern files (using
                           $PATH syntax). The default path is the current directory (see mbk(1)).

       MBK_WORK_LIB        specifies  the  current  working  directory.  The  working   directory
                           idicates the place where all output files are written.

       MBK_CATAL_NAME      Indicates  the file where the behavioral description files are listed.
                           This file is used to  leaf  cells  of  a  structural  description.(see
                           mbk(1))

       MBK_IN_LO           file extension for structural entity. (see mbk(1))

       VH_BEHSFX           list of file extensions for behavioural entities (using $PATH syntax).
                           The default file extension is vbe.

       VH_PATSFX           list of file extensions for pattern description entities (using  $PATH
                           syntax).  The default file extension is pat.

       VH_DLYSFX           list  of  file extensions for delays description entities (using $PATH
                           syntax).  The default file extension is dly.

       VH_MAXERR           maximum number of errors  allowed  during  simulation  phase.  If  the
                           number  of  errors occured during simulation reaches VH_MAXERR, asimut
                           stops the simulation at the end of  processing  the  current  pattern.
                           Patterns  following  the  current  pattern  remain unprocessed and are
                           reproduced in the result file.  The default value of VH_MAXERR is 10.

       root_file is the name of the description.

       By default asimut looks for a structural description. It uses  the  MBK_IN_LO  environment
       variables  to  identify both the format and the extension of structural description files.
       To load structural VHDL files MBK_IN_LO must be set to vst.

       To load a pure behavioural description -b option must be specified. In such a case  asimut
       loads  a  data  flow  VHDL  description file. The VH_BEHSFX environment variable gives the
       extensions to be used.

       pattern_file is the entity name of the  pattern  description.  The  file  containing  this
       entity  must  be  named  pattern_file.ext , where ext is one of the extension specified in
       VH_PATSFX.

       result_file is the  result  file  produced  by  asimut.  The  result  file  is  a  pattern
       description file with the extension specified by VH_PATSFX.

OPTIONS

       -b                  consider the root_file description as a behavioural description

       -backdelay [min, max, typ] delay_file
                           use file delay_file.ext for delays backannotation, where ext is one of
                           the extension specified in VH_DLYSFX.

       -bdd                use BDDs (Binary Decision Diagram)  to  represent  expressions.  Using
                           this  option  makes  the  simulation be two times faster but increases
                           memory requirement

       -c                  run only the compilation stage

       -core core_file     at the first error encountered, dump the state of the circuit in  both
                           an  ascii  file (suffixed .cor) and a binary save file (suffixed .sav)
                           which can be used as initialization file in a further session. If  the
                           -nores option is specified a pattern file is also produced.

       -dbg[sbpldc]        call the debugger (developper usage)

       -defaultdelay (-dd) only  null  delays  (no  after clause in the VHDL file) are changed if
                           backannotated delays or fixed delays are specified.

       -fixeddelay value (-fd value)
                           all delays of the description are fixed to value.

       -h                  display this help file

       -i value            initialize all signals of the description with value. Value can  be  0
                           or 1

       -i save_file        read a save file and use it to initialize the state of the description
                           before processing the first pattern (the file name cannot be 1 nor 0)

       -inspect instance_name
                           produce a pattern file corresponding to the interface of the  instance
                           identified by instance-name

       -l n                print at most n characters for pattern labels. The default value for n
                           is 15.

       -nores              do not generate result file

       -p n                load at most n patterns from input pattern file each time. Using  this
                           feature  reduces memory allocation when a great number of patterns are
                           to be simulated. In addition after the n patterns have been processed,
                           the  simulation  result  is  printed  in  the result pattern file. The
                           default value for n is 0 which makes the whole pattern file be loaded.

       -t                  trace signals when making BDDs (developper usage).

       -transport          use transport delay model (default is inertial).

       -zerodelay (-zd)    all the delays of the VHDL description are supposed to be null delays.

EXAMPLE

       asimut -b -i init_add adder_32 adder_patterns res_add

       simulates a behavioural description held in the file named 'adder_32.vbe using the pattern
       file  `adder_patterns.pat'.  The  simulation results is written into 'res_add.pat' and the
       description is initialized with the values contained in 'init_add.sav'.

DIAGNOSTICS

       Register initializations in the pattern file allows changing the value of a register  into
       a  known  value. However, using this feature to initialize a register before executing the
       first  pattern  is  not  recommended.  Registers  value  (defined  by  the  initialization
       statement)  may be overwritten since description has not a coherent state before the first
       pattern.

SEE ALSO

       vhdl(5), pat(5), genpat(1), mbk(1)