rom/graphics/bltclear.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Graphics function BltClear()
   6     Lang: english
   7 */
   8 #include "graphics_intern.h"
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <proto/graphics.h>
  14
  15         AROS_LH3(void, BltClear,
  16
  17 /*  SYNOPSIS */
  18         AROS_LHA(void *, memBlock, A1),
  19         AROS_LHA(ULONG , bytecount, D0),
  20         AROS_LHA(ULONG , flags, D1),
  21
  22 /*  LOCATION */
  23         struct GfxBase *, GfxBase, 50, Graphics)
  24
  25 /*  FUNCTION
  26         Use the blitter for clearing a block of Chip-Ram.
  27
  28     INPUTS
  29         memBlock  - pointer to beginning of memory to be cleared
  30         flags     - set bit 0 to force function to wait until
  31                     the blitter - if used - is done
  32                     set bit 1 for row/bytesperrow - mode
  33         bytecount - if bit 1 is set to 1: bytecount contains an even number
  34                                           of bytes to clear
  35                     if bit 1 is set to 0: low 16 bits are taken as number of
  36                                           bytes per row and upper 16 bits
  37                                           are taken as number of rows.
  38
  39     RESULT
  40         A cleared block of Chip-Ram.
  41
  42     NOTES
  43         THIS FUNCTION IS DEPRECATED except if you want to simply clear
  44         some memory.
  45
  46     EXAMPLE
  47
  48     BUGS
  49
  50     SEE ALSO
  51         InitGels(), Animate(), graphics/rastport.h, graphics/gels.h
  52
  53     INTERNALS
  54
  55     HISTORY
  56
  57 *****************************************************************************/
  58 {
  59   AROS_LIBFUNC_INIT
  60
  61   ULONG count, end;
  62
  63   if (0 != (flags & 2) )
  64     /* use row/bytesperrow */
  65     bytecount = (bytecount & 0xFFFF) * (bytecount >> 16);
  66
  67   /* we have an even number of BYTES to clear here */
  68   /* but use LONGS for clearing the block */
  69   count = 0;
  70   end = bytecount >> 2;
  71   while(count < end)
  72     ((ULONG *)memBlock)[count++] = 0;
  73   /* see whether we had an odd number of WORDS */
  74   if (0 != (bytecount & 2))
  75     ((UWORD *)memBlock)[(count * 2)] = 0;
  76
  77   AROS_LIBFUNC_EXIT
  78 } /* BltClear */