Provided by: freehdl_0.0.7-1.2ubuntu1_amd64 bug

NAME

       v2cc.libs - VHDL library mapping file for the FreeHDL compiler/simulator.

DESCRIPTION

       FreeHDL is a compiler/simulator suite for the hardware description language VHDL.  VHDL'93
       as well as VHDL'87 standards are supported.

       FreeHDL translates the original VHDL source FILEs into C++. Then, the C++  source  can  be
       compiled  and linked to the kernel to build the simulation program. Starting the generated
       executable will simulate the  corresponding  VHDL  model.  The  actual  build  process  to
       generate  the  simulator from the VHDL source is a complex process which is handled by the
       gvhdl script.

       FreeHDL does not have a opaque notion of  design  libraries.   VHDL  files  are  not  pre-
       analyzed  and  checked  into  some  library  data base as in other VHDL compiler/simulator
       systems.  Instead, whenever a reference to a design unit needs to be made, FreeHDL  parses
       the  VHDL code of that design unit from fresh.  Therefore, it needs to be able to find the
       source file of a design unit given the VHDL name of that unit.

       Thus, as far as FreeHDL is concerned, a design library is a mapping from VHDL  identifiers
       to file names.  There is also a mapping for getting library names from mapping files.

       Such  a  mapping  is  specified via a "mapping file".  It contains a list of pattern rules
       that each transform a certain class of identifiers into file names.

       The syntax of a mapping file is:

         Lexical:

            litchar: 'a'..'z' | 'A'..'Z' | '0'..'9' | '_' | '/' | '-' | '.' escchar

            escchar: '\' char

            whitespace: ' ' | '\n' | '\v' | '\t' | comment

            comment: '#' any_character* '\n'

            opchar: ':' | ',' | '(' | ')'

            specchar: every printable char except litchar, whitespace and opchar

            symchar: litchar | specchar

            symbol: symchar+

         Grammar:

            mapping: version patternrule*

            version: "v2cc_mapfile" "0"

            patternrule: symbol [ ':' symbol ]

       Comments are ignored.

       A mapping files specifies a sequence of pattern rules.  When transforming  an  identifier,
       each rule is tried in turn and the first one that matches is chosen.

       A rule looks like

         pattern: filename

       When  the  ":  filename"  part  is  omitted,  it  defaults  to "patternEXT" where "EXT" is
       determined by the user of the mapping file.

       The "pattern" can contain the special character "<" which introduces  a  `wildcard'.   The
       "<" must be followed by a ">", with arbitrary characters inbetween.  These characters form
       the name of the wildcard.  A wildcard matches any sequence of characters.   There  can  be
       any number of wildcards in the pattern, but each must have a unique name.

       The  "filename"  can  also contain the character "<", followed by a name, followed by ">".
       There, it introduces a `wildcard substitution'.  It will be replaced with  the  characters
       that  matched  the wildcard with the same name in "pattern".  When there is no wildcard in
       "pattern" with the right name, it  will  be  replaced  with  nothing.   While  doing  this
       replacement,  the  characters "#" and "/" are replaced as "##", and "#-" respectively.  No
       other character translations are done, so if  you  have  funny  characters  in  your  VHDL
       identifiers, you will have funny characters in your filenames.

       Before  doing  the  comparison  with  the  patterns, the VHDL identifier is brought into a
       canonical form: when it is not an abstract identifier, all its characters are down-cased.

       When the resulting filename is relative (does not begin with "/"), it is prefixed with the
       directory of the mapping file.

       A non-existent mapping file is equivalent to the single rule

         <>

       An empty mapping file is just that: an empty mapping.

       The  mapping  does not need to be reversible.  It is OK when multiple identifiers map to a
       single filename.

       No special character besides "<" and ">" is valid in "pattern" or  "filename".   They  are
       reserved for future extensions.

       The  mapping files for going from design unit names to filenames are found by looking into
       directories specified by the `v2cc library path'.  You can use  the  environment  variable
       V2CC_LIBRARY_PATH  and  command  line  options  to  define the path.  When the environment
       variable is not set, it defaults to a value that makes the  standard  libraries  available
       that  are  distributed  and  installed  with  v2cc  itself.  When it is set, it completely
       overwrites this default value.

       The variable V2CC_LIBRARY_PATH consists of ":" separated filenames.  The filename  "*"  is
       replaced with the default value mentioned above.

       In  addition  to the environment variable, you can use the "-L libdir" command line option
       with v2cc.  The directories specified with "-L" are added in front of the  ones  specified
       by  V2CC_LIBRARY_PATH.  In the final library path, they appear in the same order as on the
       command line.

       Looking for a design unit named UNIT in a library named LIB is done like this:

            for each component of the library path, L
              if L is a regular file
                set LMAP to L
              else if L is a directory
                set LMAP to L/v2cc.libs
              else
                continue with next component
              translate LIB into FLIB using LMAP with EXT=""
              if FLIB.vhdl exists
                terminate with FLIB.vhdl as the result
              if FLIB.v2cc exists
                set UMAP to FLIB.v2cc
              else if FLIB is a directory
                set UMAP to FLIB/v2cc.units
              else
                continue with next component
              translate UNIT into FUNIT using UMAP with EXT=".vhdl"
              terminate with FUNIT as the result
            terminate unsuccessfully

       This mechanism is used for all design units that are referenced from within VHDL code  (or
       via  other means).  There is a complication with architectures and package bodies, though,
       because they are not uniquely identified by a single identifier.  For them,  a  artificial
       identifier is constructed.  Architectures get names of the form

           <entity>(<architecture>)

       while package bodies become

           <package>(body)

       For  example,  "architecture  struct of model" is turned into "model(struct)" and "package
       body misc" is turned into "misc(body)".

       When a design file contains multiple design  units,  they  are  all  parsed,  checked  for
       correctness  and  remembered,  but  only the needed unit will be used for code generation.
       That is, when a design file contains both a package header and  a  package  body  and  the
       package  header  is referenced from another design unit, no code will be generated for the
       package body.  When one of the  ignored  units  will  be  referenced  later  in  the  same
       invocation  of  v2cc,  the design file will not be read again because all design units are
       retained in core.

EXAMPLES

       The simplest situation is when you have no mapping files at all.  A design library is then
       a  directory  on  your library path.  The name of that directory is that of the library in
       VHDL.  Each file in that directory with a ".vhdl" extension is used for a design unit with
       the same name as the file without the extension.

       Say you have this directory structure

           somedir/
             std/
               standard.vhdl
               textio.vhdl
             ieee/
               numeric_bit.vhdl
               std_logic_1164.vhdl

       When you put "somedir" into your library path, you have access to the design units

              STD.STANDARD
              STD.TEXTIO
              IEEE.NUMERIC_BIT
              IEEE.STD_LOGIC_1164

       In  this  situation, you have one file per design unit.  When you have one file per design
       library, it would look like this

           somedir/
             fmf.vhdl

       All references to design units in the FMF design library would be routed to "fmf.vhdl".

       As another example assume that all VHDL libraries are mapped into  subdirs  starting  from
       root  directory  "/foo".  Further,  assume  that there are VHDL libraries named "lib1" and
       "lib2". They shall be mapped to subdir "/foo/lib1_dir"  and  "/foo/lib2_dir".  Hence,  the
       file/directory structure is as follows:

       /foo                 <-   library  root  directory /foo/v2cc.libs      <-  mapping control
       file  /foo/lib1_dir       <-  library dir for VHDL library  lib1  /foo/lib1_dir/comp1.vhdl
       <-  file  that  contains  VHDL  model  comp1  /foo/lib2_dir       <-  library dir for VHDL
       library lib2 /foo/lib2_dir/comp2.vhdl <- file that contains VHDL model comp2

       Then, file "/foo/v2cc.libs" should contain:

       v2cc_mapfile 0 lib1 : lib1_dir lib2 : lib2_dir

       In order to compile a design named comp1 (stored in file  comp1.vhdl)  into  VHDL  library
       lib1 goto subdir "/foo/lib1_dir" and execute:

           gvhdl -c -L .. -l lib1 comp1.vhdl

       Note  that  option  "-l  lib1"  forces  the  compiler  to  associate  the  model stored in
       "comp1.vhdl" with VHDL library lib1.  Note further,  that  the  compiler  switch  "-L  .."
       specifies  the  path to the directory where "v2cc.libs" is stored. You may also specify an
       absolute path:

           gvhdl -c -L /foo -l lib1 comp1.vhdl

       Note that comp1 should reside in a file named "comp1.vhdl".

       If  lib2  contains  a  design  comp2  that  makes  use  of  comp1  from  lib1  then   goto
       "/foo/lib2_dir" and run the following command to create an executable for model comp2:

           gvhdl -L .. -l lib2 comp2.vhdl ../lib1_dir/comp1.o

SEE ALSO

       gvhdl(1), freehdl-v2cc(1), freehdl-config(1)

AVAILABILITY

       The latest version of FreeHDL can always be obtained from www.freehdl.seul.org

REPORTING BUGS

       Known bugs are documented within the BUGS file.  If your report addresses a parser related
       topic then contact Marius Vollmer <mvo@zagadka.ping.de>.  If it is  related  to  the  code
       generator  or  compiler  then  send  an  email  to  Edwin Naroska <edwin@ds.e-technik.uni-
       dortmund.de>.  If your are not sure send it to Edwin.  He will  take  care  of  forwarding
       your report to the appropriate recipient.

COPYRIGHT

       Edwin  Naroska  ©  1999,  2000,  2001,  2002,  2003,  2004,  2005 <edwin@ds.e-technik.uni-
       dortmund.de>

       This is free software; see the source for copying conditions.  There is NO  warranty;  not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

AUTHORS

       Written by Marius Vollmer <mvo@zagadka.ping.de> and Edwin Naroska <edwin@ds.e-technik.uni-
       dortmund.de>.