posix/lib/psxdll/misc/interlock.c

   1 /* $Id: interlock.c,v 1.2 2002/02/20 09:17:57 hyperion Exp $
   2  */
   3 /*
   4  * COPYRIGHT:   See COPYING in the top level directory
   5  * PROJECT:     ReactOS POSIX+ Subsystem
   6  * FILE:        subsys/psx/lib/psxdll/misc/interlock.c
   7  * PURPOSE:     inter-locked increments/decrements
   8  * PROGRAMMER:  KJK::Hyperion <noog@libero.it>
   9  * UPDATE HISTORY:
  10  *              20/01/2002: Adapted from lib/kernel32/synch/intrlck.c
  11  */
  12
  13 /*
  14  * NOTE by KJK::Hyperion: I do not understand what's behind these functions.
  15  *                        Don't ask me how they work, or to fix errors in them.
  16  *                        Please refer to the authors referenced in the original
  17  *                        file, lib/kernel32/synch/intrlck.c
  18  */
  19
  20 /* TODO? move these in some shared library */
  21
  22 #include <psx/interlock.h>
  23
  24 int __interlock_inc(int * addend)
  25 {
  26  int ret = 0;
  27
  28  __asm__
  29  (
  30   "     lock\n" /* for SMP systems */
  31   "     incl    (%1)\n"
  32   "     je      2f\n"
  33   "     jl      1f\n"
  34   "     incl    %0\n"
  35   "     jmp     2f\n"
  36   "1:   dec     %0\n"
  37   "2:\n"
  38   :"=r" (ret):"r" (addend), "0" (0): "memory"
  39  );
  40
  41  return (ret);
  42 }
  43
  44 int __interlock_dec(int * addend)
  45 {
  46  int ret = 0;
  47
  48  __asm__
  49  (
  50   "     lock\n" /* for SMP systems */
  51   "     decl    (%1)\n"
  52   "     je      2f\n"
  53   "     jl      1f\n"
  54   "     incl    %0\n"
  55   "     jmp     2f\n"
  56   "1:   dec     %0\n"
  57   "2:\n"
  58   :"=r" (ret):"r" (addend), "0" (0): "memory"
  59  );
  60
  61  return (ret);
  62
  63 }
  64
  65 int __interlock_add(int * addend, int increment)
  66 {
  67  int ret = 0;
  68
  69  __asm__
  70  (
  71   "     lock\n" /* for SMP systems */
  72   "     xaddl %0,(%1)"
  73   :"=r" (ret)
  74   :"r"  (addend), "0" (increment)
  75   :"memory"
  76  );
  77
  78  return (ret);
  79
  80 }
  81
  82 /* EOF */
  83