reactos/lib/kernel32/synch/intrlck.c

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS system libraries
   4  * FILE:            lib/kernel32/sync/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  */
  16
  17
  18 /************************************************************************
  19 *           InterlockedIncrement                                        *
  20 *                                                                       *
  21 * InterlockedIncrement adds 1 to a long variable and returns            *
  22 *  -  a negative number if the result < 0                               *
  23 *  -  zero if the result == 0                                           *
  24 *  -  a positive number if the result > 0                               *
  25 *                                                                       *
  26 * The returned number need not be equal to the result!!!!               *
  27 * note:                                                                 *
  28 *                                                                       *
  29 ************************************************************************/
  30
  31 #include <k32.h>
  32
  33 LONG
  34 STDCALL
  35 InterlockedIncrement(PLONG Addend)
  36 {
  37         long ret = 0;
  38         __asm__
  39         (
  40            "\tlock\n"   /* for SMP systems */
  41            "\tincl      (%1)\n"
  42            "\tje        2f\n"
  43            "\tjl        1f\n"
  44            "\tincl      %0\n"
  45            "\tjmp       2f\n"
  46            "1:\tdec     %0\n"
  47            "2:\n"
  48            :"=r" (ret):"r" (Addend), "0" (0): "memory"
  49         );
  50         return ret;
  51 }
  52
  53 /************************************************************************
  54 *           InterlockedDecrement                                        *
  55 *                                                                       *
  56 * InterlockedIncrement adds 1 to a long variable and returns            *
  57 *  -  a negative number if the result < 0                               *
  58 *  -  zero if the result == 0                                           *
  59 *  -  a positive number if the result > 0                               *
  60 *                                                                       *
  61 * The returned number need not be equal to the result!!!!               *
  62 ************************************************************************/
  63
  64 LONG
  65 STDCALL
  66 InterlockedDecrement(LPLONG lpAddend)
  67 {
  68         long ret;
  69         __asm__
  70         (
  71            "\tlock\n"   /* for SMP systems */
  72            "\tdecl      (%1)\n"
  73            "\tje        2f\n"
  74            "\tjl        1f\n"
  75            "\tincl      %0\n"
  76            "\tjmp       2f\n"
  77            "1:\tdec     %0\n"
  78            "2:\n"
  79            :"=r" (ret):"r" (lpAddend), "0" (0): "memory"
  80         );
  81         return ret;
  82
  83
  84 }
  85
  86 /************************************************************************
  87  *           InterlockedExchange
  88  *
  89  * Atomically exchanges a pair of values.
  90  *
  91  * RETURNS
  92  *      Prior value of value pointed to by Target
  93  */
  94
  95 LONG
  96 STDCALL
  97 InterlockedExchange(LPLONG target, LONG value )
  98 {
  99
 100         long ret;
 101         __asm__ ( /* lock for SMP systems */
 102                   "lock\n\txchgl %0,(%1)"
 103                   :"=r" (ret):"r" (target), "0" (value):"memory" );
 104         return ret;
 105
 106
 107 }
 108
 109 /************************************************************************
 110  *           InterlockedCompareExchange
 111  *
 112  * Atomically compares Destination and Comperand, and if found equal exchanges
 113  * the value of Destination with Exchange
 114  *
 115  * RETURNS
 116  *      Prior value of value pointed to by Destination
 117  */
 118 PVOID
 119 STDCALL
 120 InterlockedCompareExchange(
 121             PVOID *Destination,
 122             PVOID Exchange,
 123             PVOID Comperand     )
 124 {
 125         PVOID ret;
 126         __asm__ ( /* lock for SMP systems */
 127                   "lock\n\t"
 128                   "cmpxchgl %2,(%1)"
 129                   :"=r" (ret)
 130                   :"r" (Destination),"r" (Exchange), "0" (Comperand)
 131                   :"memory" );
 132         return ret;
 133
 134 }
 135
 136 /************************************************************************
 137  *           InterlockedExchangeAdd
 138  *
 139  * Atomically adds Increment to Addend and returns the previous value of
 140  * Addend
 141  *
 142  * RETURNS
 143  *      Prior value of value pointed to by Addend
 144  */
 145 LONG
 146 STDCALL
 147 InterlockedExchangeAdd(
 148             PLONG Addend,
 149             LONG Increment
 150 )
 151 {
 152
 153         LONG ret;
 154         __asm__ ( /* lock for SMP systems */
 155                   "lock\n\t"
 156                   "xaddl %0,(%1)"
 157                   :"=r" (ret)
 158                   :"r" (Addend), "0" (Increment)
 159                   :"memory" );
 160         return ret;
 161
 162 }