arch/i386-pc/exec/userstate.c

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: UserState() - Return to normal mode after changing things.
   6     Lang: english
   7 */
   8
   9 /*****************************************************************************
  10
  11     NAME */
  12 #include <proto/exec.h>
  13
  14         AROS_LH1(void, UserState,
  15
  16 /*  SYNOPSIS */
  17         AROS_LHA(APTR, sysStack, D0),
  18
  19 /*  LOCATION */
  20         struct ExecBase *, SysBase, 26, Exec)
  21
  22 /*  FUNCTION
  23         Return to user mode after a call to SuperState().
  24
  25     INPUTS
  26         sysStack    -   The return value from SuperState()
  27
  28     RESULT
  29         The system will be back to normal.
  30
  31     NOTES
  32
  33     EXAMPLE
  34
  35     BUGS
  36
  37     SEE ALSO
  38         SuperState(), Supervisor()
  39
  40     INTERNALS
  41         Undo SuperState()
  42
  43     HISTORY
  44
  45 ******************************************************************************/
  46 {
  47     AROS_LIBFUNC_INIT
  48
  49     /* By default there is nothing to do. */
  50
  51         __asm__ __volatile
  52                 (
  53                         "movl %%esp,0x0c(%%eax)\n\t"    /* put USP onto exception stack frame */
  54                         "movl %%eax,%%esp\n\t"                  /* SSP = SP */
  55                         "leal   1f,%%eax\n\t"
  56                         "movl   %%eax,(%%esp)\n\t"              /* return at this address */
  57                         "iret\n"
  58                         "1:"
  59                         :
  60                         :"a"(sysStack)
  61                 );
  62
  63     AROS_LIBFUNC_EXIT
  64 } /* UserState() */