rom/graphics/ownblitter.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Try to own the blitter for private usage
   6     Lang: english
   7 */
   8
   9 #include <aros/debug.h>
  10
  11 #include <proto/exec.h>
  12 #include <graphics/gfxbase.h>
  13 #include <exec/execbase.h>
  14 #include <exec/tasks.h>
  15
  16 #include "graphics_intern.h"
  17 #include "gfxfuncsupport.h"
  18
  19 /*****************************************************************************
  20
  21     NAME */
  22 #include <proto/graphics.h>
  23
  24         AROS_LH0(void, OwnBlitter,
  25
  26 /*  SYNOPSIS */
  27
  28
  29 /*  LOCATION */
  30         struct GfxBase *, GfxBase, 76, Graphics)
  31
  32 /*  FUNCTION
  33         The blitter is allocated for exclusive use by the calling task.
  34         This function returns immediately if no other task is using
  35         the blitter right now or if no blits are in the queues (QBlit(),
  36         QBSBlit()). Otherwise the function will block until the blitter
  37         can be accessed.
  38         It is good practice to start the blitter immediately after calling
  39         this function and then call DisownBlitter() so other tasks can
  40         use the blitter.
  41
  42     INPUTS
  43
  44     RESULT
  45
  46     NOTES
  47
  48     EXAMPLE
  49
  50     BUGS
  51
  52     SEE ALSO
  53         DisownBlitter()
  54
  55     INTERNALS
  56
  57     HISTORY
  58
  59 ******************************************************************************/
  60 {
  61   AROS_LIBFUNC_INIT
  62
  63   struct BlitWaitQNode node;
  64   struct Task *me;
  65
  66   me = FindTask(NULL);
  67
  68   D(bug("OwnBlitter: Request by Task %p)\n", me));
  69
  70   Disable();
  71   for (;;) {
  72     if (GfxBase->BlitOwner == NULL) {
  73       GfxBase->BlitOwner = me;
  74       Enable();
  75       D(bug("OwnBlitter: Now owned by Task %p\n", me));
  76       return;
  77     }
  78     node.task = me;
  79     AddTail(&GfxBase->BlitWaitQ, (struct Node*)&node);
  80     SetSignal(0, 1 << SIGB_BLIT);
  81     Wait(1 << SIGB_BLIT);
  82     Remove((struct Node*)&node);
  83   }
  84
  85   AROS_LIBFUNC_EXIT
  86 } /* OwnBlitter */