reactos/lib/intrlck/i386/exchangeadd.c

   1 /*
   2  * PROJECT:     ReactOS system libraries
   3  * LICENSE:     GPL - See COPYING in the top level directory
   4  * FILE:        lib/intrlck/i386/exchangeadd.c
   5  * PURPOSE:     Inter lock exchange adds
   6  * PROGRAMMERS: Copyright 1995 Martin von Loewis
   7  *              Copyright 1997 Onno Hovers
   8  */
   9
  10 /************************************************************************
  11  *           InterlockedExchangeAdd
  12  *
  13  * Atomically adds Increment to Addend and returns the previous value of
  14  * Addend
  15  *
  16  * RETURNS
  17  *      Prior value of value pointed to by Addend
  18  */
  19
  20 /*
  21  * LONG NTAPI InterlockedExchangeAdd(PLONG Addend, LONG Increment)
  22  */
  23
  24 #include <windows.h>
  25 LONG
  26 NTAPI
  27 InterlockedExchangeAdd(
  28         IN OUT LONG volatile *Addend,
  29         LONG Increment)
  30 {
  31         LONG ret;
  32         __asm__ (
  33                 /* lock for SMP systems */
  34                 "lock\n\t"
  35                 "xaddl %0,(%1)"
  36                 :"=r" (ret)
  37                 :"r" (Addend), "0" (Increment)
  38                 :"memory" );
  39         return ret;
  40 }