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ASIMUT(1)		    cao-vlsi reference manual		       ASIMUT(1)

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 descrip-
     tion 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	informa-
     tion about the supported subset of VHDL.

     Once  a  hardware description is loaded, asimut looks for a simulation pat-
     tern 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 de-
     scription 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.  Us-
     ing this mechanism, a large sequence of patterns can be breaked  onto  sev-
     eral  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  indicates  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  enti-
			 ties  (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 occurred during  simula-
			 tion  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 envi-
     ronment variable gives the extensions to be used.

     pattern_file is the entity name of the pattern description. The  file  con-
     taining  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 de-
			 scription

     -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 expres-
			 sions.  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 bi-
			 nary  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 (developer 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 de-
			 fault 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 ad-
			 dition 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 (developer 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 val-
     ues 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)

ASIM/LIP6			 October 1, 1997		       ASIMUT(1)

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