reactos/lib/intrlck/i386/exchange.c

   1 /*
   2  * PROJECT:     ReactOS system libraries
   3  * LICENSE:     GPL - See COPYING in the top level directory
   4  * FILE:        lib/intrlck/i386/exchange.c
   5  * PURPOSE:     Inter lock exchanges
   6  * PROGRAMMERS: Copyright 1995 Martin von Loewis
   7  *              Copyright 1997 Onno Hovers
   8  */
   9
  10 /************************************************************************
  11  *           InterlockedExchange
  12  *
  13  * Atomically exchanges a pair of values.
  14  *
  15  * RETURNS
  16  *      Prior value of value pointed to by Target
  17  */
  18
  19 /*
  20  * LONG NTAPI InterlockedExchange(LPLONG target, LONG value)
  21  */
  22
  23 #include <windows.h>
  24 LONG
  25 NTAPI
  26 InterlockedExchange(LPLONG target, LONG value)
  27 {
  28         LONG ret;
  29         __asm__ (
  30                 /* lock for SMP systems */
  31                 "lock\n\txchgl %0,(%1)"
  32                 :"=r" (ret):"r" (target), "0" (value):"memory" );
  33         return ret;
  34 }