arch/.unmaintained/m68k-native/exec/setsr.s

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 /*****************************************************************************
   7
   8     NAME
   9
  10         AROS_LH2(ULONG, SetSR,
  11
  12     SYNOPSIS
  13         AROS_LHA(ULONG, newSR, D0),
  14         AROS_LHA(ULONG, mask,  D1),
  15
  16     LOCATION
  17         struct ExecBase *, SysBase, 24, Exec)
  18
  19     FUNCTION
  20         Read/Modify the CPU status register in an easy way. Only the bits set in
  21         the mask parameter will be changed.
  22
  23     INPUTS
  24         newSR - New contents of sr.
  25         mask  - Bits to change.
  26
  27     RESULT
  28         Old contents of sr.
  29
  30     NOTES
  31
  32     EXAMPLE
  33
  34     BUGS
  35
  36     SEE ALSO
  37
  38     INTERNALS
  39
  40     HISTORY
  41
  42 ******************************************************************************/
  43
  44         #include "machine.i"
  45
  46         .text
  47         .balign 4
  48         .globl  AROS_SLIB_ENTRY(SetSR,Exec)
  49         .type   AROS_SLIB_ENTRY(SetSR,Exec),@function
  50 AROS_SLIB_ENTRY(SetSR,Exec):
  51         /* Do the real work in supervisor mode
  52            Preserve a5 in a0 (faster than stack space)
  53         */
  54         move.l  a5,a0
  55         lea.l   setsrsup,a5
  56         jsr     Supervisor(a6)
  57         move.l  a0,a5
  58         rts
  59
  60 setsrsup:
  61         /* The old value of sr now lies on the top of the stack.
  62            d1 = (mask & newSR) | (~mask & SR)
  63         */
  64         and.w   d1,d0
  65         eor.w   #-1,d1
  66         and.w   (sp),d1
  67         or.w    d0,d1
  68
  69         /* Get returncode */
  70         clr.l   d0
  71         move.w  (sp),d0
  72
  73         /* Set new sr value */
  74         move.w  d1,(sp)
  75         rte
  76