gcc/m2/gm2-libs/MemUtils.mod

   1 (* MemUtils.mod provides some basic memory utilities.
   2
   3 Copyright (C) 2001-2024 Free Software Foundation, Inc.
   4 Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.
   5
   6 This file is part of GNU Modula-2.
   7
   8 GNU Modula-2 is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GNU Modula-2 is distributed in the hope that it will be useful, but
  14 WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 General Public License for more details.
  17
  18 Under Section 7 of GPL version 3, you are granted additional
  19 permissions described in the GCC Runtime Library Exception, version
  20 3.1, as published by the Free Software Foundation.
  21
  22 You should have received a copy of the GNU General Public License and
  23 a copy of the GCC Runtime Library Exception along with this program;
  24 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  25 <http://www.gnu.org/licenses/>.  *)
  26
  27 IMPLEMENTATION MODULE MemUtils ;
  28
  29
  30 FROM SYSTEM IMPORT WORD, BYTE, TSIZE ;
  31
  32
  33 (*
  34    MemCopy - copys a region of memory to the required destination.
  35 *)
  36
  37 PROCEDURE MemCopy (from: ADDRESS; length: CARDINAL; to: ADDRESS) ;
  38 VAR
  39    pwb, pwa: POINTER TO WORD ;
  40    pbb, pba: POINTER TO BYTE ;
  41 BEGIN
  42    WHILE length>=TSIZE(WORD) DO
  43       pwa := from ;
  44       pwb := to ;
  45       pwb^ := pwa^ ;
  46       INC(from  , TSIZE(WORD)) ;
  47       INC(to    , TSIZE(WORD)) ;
  48       DEC(length, TSIZE(WORD))
  49    END ;
  50    WHILE length>0 DO
  51       pba := from ;
  52       pbb := to ;
  53       pbb^ := pba^ ;
  54       INC(from  , TSIZE(BYTE)) ;
  55       INC(to    , TSIZE(BYTE)) ;
  56       DEC(length, TSIZE(BYTE))
  57    END
  58 END MemCopy ;
  59
  60
  61 (*
  62    MemZero - sets a region of memory: a..a+length to zero.
  63 *)
  64
  65 PROCEDURE MemZero (a: ADDRESS; length: CARDINAL) ;
  66 VAR
  67    pwa: POINTER TO WORD ;
  68    pba: POINTER TO BYTE ;
  69 BEGIN
  70    pwa := a ;
  71    WHILE length>=TSIZE(WORD) DO
  72       pwa^ := WORD(0) ;
  73       INC(pwa, TSIZE(WORD)) ;
  74       DEC(length, TSIZE(WORD))
  75    END ;
  76    pba := ADDRESS(pwa) ;
  77    WHILE length>=TSIZE(BYTE) DO
  78       pba^ := BYTE(0) ;
  79       INC(pba, TSIZE(BYTE)) ;
  80       DEC(length, TSIZE(BYTE))
  81    END
  82 END MemZero ;
  83
  84
  85 END MemUtils.