lib/ntdll/rtl/intrlck.c

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS system libraries
   4  * FILE:            lib/ntdll/rtl/intrlck.c
   5  * PURPOSE:         Inter lock increments
   6  * UPDATE HISTORY:
   7  *                  Created 30/09/99
   8  */
   9
  10 /*
  11  * Win32 kernel functions
  12  *
  13  * Copyright 1995 Martin von Loewis
  14  * Copyright 1997 Onno Hovers
  15  * Copied from kernel32
  16  */
  17
  18
  19 /************************************************************************
  20 *           InterlockedIncrement                                        *
  21 *                                                                       *
  22 * InterlockedIncrement adds 1 to a long variable and returns            *
  23 *  -  a negative number if the result < 0                               *
  24 *  -  zero if the result == 0                                           *
  25 *  -  a positive number if the result > 0                               *
  26 *                                                                       *
  27 * The returned number need not be equal to the result!!!!               *
  28 * note:                                                                 *
  29 *                                                                       *
  30 ************************************************************************/
  31
  32 #include <windows.h>
  33
  34 LONG
  35 STDCALL
  36 InterlockedIncrement(PLONG Addend)
  37 {
  38         long ret = 0;
  39         __asm__
  40         (
  41            "\tlock\n"   /* for SMP systems */
  42            "\tincl      (%1)\n"
  43            "\tje        2f\n"
  44            "\tjl        1f\n"
  45            "\tincl      %0\n"
  46            "\tjmp       2f\n"
  47            "1:\tdec     %0\n"
  48            "2:\n"
  49            :"=r" (ret):"r" (Addend), "0" (0): "memory"
  50         );
  51         return ret;
  52 }
  53
  54 /************************************************************************
  55 *           InterlockedDecrement                                        *
  56 *                                                                       *
  57 * InterlockedIncrement adds 1 to a long variable and returns            *
  58 *  -  a negative number if the result < 0                               *
  59 *  -  zero if the result == 0                                           *
  60 *  -  a positive number if the result > 0                               *
  61 *                                                                       *
  62 * The returned number need not be equal to the result!!!!               *
  63 ************************************************************************/
  64
  65 LONG
  66 STDCALL
  67 InterlockedDecrement(LPLONG lpAddend)
  68 {
  69         long ret;
  70         __asm__
  71         (
  72            "\tlock\n"   /* for SMP systems */
  73            "\tdecl      (%1)\n"
  74            "\tje        2f\n"
  75            "\tjl        1f\n"
  76            "\tincl      %0\n"
  77            "\tjmp       2f\n"
  78            "1:\tdec     %0\n"
  79            "2:\n"
  80            :"=r" (ret):"r" (lpAddend), "0" (0): "memory"
  81         );
  82         return ret;
  83
  84
  85 }
  86
  87 /************************************************************************
  88  *           InterlockedExchange
  89  *
  90  * Atomically exchanges a pair of values.
  91  *
  92  * RETURNS
  93  *      Prior value of value pointed to by Target
  94  */
  95
  96 LONG
  97 STDCALL
  98 InterlockedExchange(LPLONG target, LONG value )
  99 {
 100
 101         long ret;
 102         __asm__ ( /* lock for SMP systems */
 103                   "lock\n\txchgl %0,(%1)"
 104                   :"=r" (ret):"r" (target), "0" (value):"memory" );
 105         return ret;
 106
 107
 108 }
 109
 110 /************************************************************************
 111  *           InterlockedCompareExchange
 112  *
 113  * Atomically compares Destination and Comperand, and if found equal exchanges
 114  * the value of Destination with Exchange
 115  *
 116  * RETURNS
 117  *      Prior value of value pointed to by Destination
 118  */
 119 PVOID
 120 STDCALL
 121 InterlockedCompareExchange(
 122             PVOID *Destination,
 123             PVOID Exchange,
 124             PVOID Comperand     )
 125 {
 126         PVOID ret;
 127         __asm__ ( /* lock for SMP systems */
 128                   "lock\n\t"
 129                   "cmpxchgl %2,(%1)"
 130                   :"=r" (ret)
 131                   :"r" (Destination),"r" (Exchange), "0" (Comperand)
 132                   :"memory" );
 133         return ret;
 134
 135 }
 136
 137 /************************************************************************
 138  *           InterlockedExchangeAdd
 139  *
 140  * Atomically adds Increment to Addend and returns the previous value of
 141  * Addend
 142  *
 143  * RETURNS
 144  *      Prior value of value pointed to by Addend
 145  */
 146 LONG
 147 STDCALL
 148 InterlockedExchangeAdd(
 149             PLONG Addend,
 150             LONG Increment
 151 )
 152 {
 153
 154         LONG ret;
 155         __asm__ ( /* lock for SMP systems */
 156                   "lock\n\t"
 157                   "xaddl %0,(%1)"
 158                   :"=r" (ret)
 159                   :"r" (Addend), "0" (Increment)
 160                   :"memory" );
 161         return ret;
 162
 163 }