reactos/lib/intrlck/i386/decrement.c

   1 /*
   2  * PROJECT:     ReactOS system libraries
   3  * LICENSE:     GPL - See COPYING in the top level directory
   4  * FILE:        lib/intrlck/i386/decrement.c
   5  * PURPOSE:     Inter lock decrements
   6  * PROGRAMMERS: Copyright 1995 Martin von Loewis
   7  *              Copyright 1997 Onno Hovers
   8  */
   9
  10 /************************************************************************
  11 *           InterlockedDecrement                                        *
  12 *                                                                       *
  13 * InterlockedDecrement adds -1 to a long variable and returns           *
  14 * the resulting decremented value.                                      *
  15 *                                                                       *
  16 ************************************************************************/
  17
  18 /*
  19  * LONG NTAPI InterlockedDecrement(LPLONG lpAddend)
  20  */
  21
  22 #include <windows.h>
  23 LONG
  24 NTAPI
  25 InterlockedDecrement(LPLONG lpAddend)
  26 {
  27         LONG ret;
  28         __asm__
  29         (
  30                 "\tlock\n"  /* for SMP systems */
  31                 "\txaddl %0, (%1)\n"
  32                 "\tdecl %0\n"
  33                 :"=r" (ret)
  34                 :"r" (lpAddend), "0" (-1)
  35                 : "memory"
  36         );
  37         return ret;
  38 }