File:  [gforth] / gforth / compat / struct.fs
Revision 1.2: download - view: text, annotated - select for diffs
Fri Jun 6 17:28:13 1997 UTC (24 years, 11 months ago) by anton
Branches: MAIN
CVS tags: HEAD
Environmental query "gforth" now returns the version-string
dictionary-end and unused moved into the kernel/basics.fs
Minor gforth.el bug fixes
Major rewrite of objects.fs (not yet done)
fixed -trailing bug (with test in test/other.fs)
optimization of fields with offset 0 in struct.fs and compat/struct.fs
other changes in compat/struct.fs (not yet done)
added ansreports to compat/*.fs
documentation changes
allot now checks for dict overflow
named [IS] (compilation semantics of IS).
minor changes

    1: \ data structures (like C structs)
    2: 
    3: \ Copyright (C) 1995 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: 
   22: \ Usage example:
   23: \
   24: \ struct
   25: \     1 cells: field search-method
   26: \     1 cells: field reveal-method
   27: \ end-struct wordlist-map
   28: \
   29: \ The structure can then be extended in the following way
   30: \ wordlist-map
   31: \     1 cells: field enum-method
   32: \ end-struct ext-wordlist-map \ with the fields search-method,...,enum-method
   33: 
   34: \ This is an ANS Forth program with an environmental dependency on
   35: \ alignments that are powers of 2 (rewrite nalign for other systems)
   36: \ and with an environmental dependence on case insensitivity (convert
   37: \ everything to upper case for state sensitive systems).
   38: 
   39: \ The program uses the following words
   40: \ !!
   41: 
   42: : nalign ( addr1 n -- addr2 )
   43: \ addr2 is the aligned version of addr1 wrt the alignment size n
   44:  1- tuck +  swap invert and ;
   45: 
   46: : dofield ( -- )
   47: does> ( name execution: addr1 -- addr2 )
   48:     @ + ;
   49: 
   50: : dozerofield ( -- )
   51:     immediate
   52: does> ( name execution: -- )
   53:     drop ;
   54: 
   55: : create-field ( offset1 align1 size align "name" -- offset2 align2 )
   56:     create
   57:     >r rot r@ nalign  dup ,  ( align1 size offset  R: align )
   58:     + swap r> nalign ;
   59: 
   60: : field ( offset1 align1 size align "name" -- offset2 align2 )
   61:     \ name execution: addr1 -- addr2
   62:     3 pick >r \ this uglyness is just for optimizing with dozerofield
   63:     create-field
   64:     r>
   65:     dup if
   66: 	dofield
   67:     else
   68: 	dozerofield
   69:     then ;
   70: 
   71: : end-struct ( size align -- )
   72:     tuck nalign swap \ pad size to full alignment
   73:     2constant ;
   74: 
   75: 0 1 chars end-struct struct
   76: 
   77: \ I don't really like the "type:" syntax. Any other ideas? - anton
   78: \ Also, this seems to be somewhat general. It probably belongs to some
   79: \ other place
   80: : cells: ( n -- size align )
   81:     cells 1 aligned ;
   82: 
   83: : doubles: ( n -- size align )
   84:     2* cells 1 aligned ;
   85: 
   86: : chars: ( n -- size align )
   87:     chars 1 chars ;
   88: 
   89: : floats: ( n -- size align )
   90:     floats 1 faligned ;
   91: 
   92: : dfloats: ( n -- size align )
   93:     dfloats 1 dfaligned ;
   94: 
   95: : sfloats: ( n -- size align )
   96:     sfloats 1 sfaligned ;
   97: 
   98: : struct-align ( size align -- )
   99:     here swap nalign here - allot
  100:     drop ;
  101: 
  102: : struct-allot ( size align -- addr )
  103:     over swap struct-align
  104:     here swap allot ;
  105: 
  106: : struct-allocate ( size align -- addr ior )
  107:     drop allocate ;
  108: 
  109: : struct-alloc ( size align -- addr )
  110:     struct-allocate throw ;

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