nspr-4.8.6/mozilla/nsprpub/pr/src/md/os2/os2thred.c - nest-learning-thermostat/5.1.7/nspr - Git at Google

 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
  * The contents of this file are subject to the Mozilla Public License Version
  * 1.1 (the "License"); you may not use this file except in compliance with
  * the License. You may obtain a copy of the License at
  * http://www.mozilla.org/MPL/
  *
  * Software distributed under the License is distributed on an "AS IS" basis,
  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  * for the specific language governing rights and limitations under the
  * License.
  *
  * The Original Code is the Netscape Portable Runtime (NSPR).
  *
  * The Initial Developer of the Original Code is
  * Netscape Communications Corporation.
  * Portions created by the Initial Developer are Copyright (C) 1998-2000
  * the Initial Developer. All Rights Reserved.
  *
  * Contributor(s):
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  * in which case the provisions of the GPL or the LGPL are applicable instead
  * of those above. If you wish to allow use of your version of this file only
  * under the terms of either the GPL or the LGPL, and not to allow others to
  * use your version of this file under the terms of the MPL, indicate your
  * decision by deleting the provisions above and replace them with the notice
  * and other provisions required by the GPL or the LGPL. If you do not delete
  * the provisions above, a recipient may use your version of this file under
  * the terms of any one of the MPL, the GPL or the LGPL.
  *
  * ***** END LICENSE BLOCK ***** */

 #include "primpl.h"
 #include <process.h>  /* for _beginthread() */
 #include <signal.h>
 #include <float.h>

 /* --- globals ------------------------------------------------ */
 _NSPR_TLS*        pThreadLocalStorage = 0;
 _PRInterruptTable             _pr_interruptTable[] = { { 0 } };
 APIRET (* APIENTRY QueryThreadContext)(TID, ULONG, PCONTEXTRECORD);

 void
 _PR_MD_ENSURE_TLS(void)
 {
    if(!pThreadLocalStorage)
    {
       /* Allocate thread local storage (TLS).  Note, that only 32 bytes can
        * be allocated at a time.
        */
       int rc = DosAllocThreadLocalMemory(sizeof(_NSPR_TLS) / 4, (PULONG*)&pThreadLocalStorage);
       PR_ASSERT(rc == NO_ERROR);
       memset(pThreadLocalStorage, 0, sizeof(_NSPR_TLS));
    }
 }

 void
 _PR_MD_EARLY_INIT()
 {
    HMODULE hmod;

    if (DosLoadModule(NULL, 0, "DOSCALL1", &hmod) == 0)
        DosQueryProcAddr(hmod, 877, "DOSQUERYTHREADCONTEXT",
                         (PFN *)&QueryThreadContext);
 }

 static void
 _pr_SetThreadMDHandle(PRThread *thread)
 {
    PTIB ptib;
    PPIB ppib;
    PRUword rc;

    rc = DosGetInfoBlocks(&ptib, &ppib);

    thread->md.handle = ptib->tib_ptib2->tib2_ultid;
 }

 /* On OS/2, some system function calls seem to change the FPU control word,
  * such that we crash with a floating underflow exception.  The FIX_FPU() call
  * in jsnum.c does not always work, as sometimes FIX_FPU() is called BEFORE the
  * OS/2 system call that horks the FPU control word.  So, we set an exception
  * handler that covers any floating point exceptions and resets the FPU CW to
  * the required value.
  */
 static ULONG
 _System OS2_FloatExcpHandler(PEXCEPTIONREPORTRECORD p1,
                              PEXCEPTIONREGISTRATIONRECORD p2,
                              PCONTEXTRECORD p3,
                              PVOID pv)
 {
 #ifdef DEBUG_pedemonte
     printf("Entering exception handler; ExceptionNum = %x\n", p1->ExceptionNum);
     switch(p1->ExceptionNum) {
         case XCPT_FLOAT_DENORMAL_OPERAND:
             printf("got XCPT_FLOAT_DENORMAL_OPERAND\n");
             break;
         case XCPT_FLOAT_DIVIDE_BY_ZERO:
             printf("got XCPT_FLOAT_DIVIDE_BY_ZERO\n");
             break;
         case XCPT_FLOAT_INEXACT_RESULT:
             printf("got XCPT_FLOAT_INEXACT_RESULT\n");
             break;
         case XCPT_FLOAT_INVALID_OPERATION:
             printf("got XCPT_FLOAT_INVALID_OPERATION\n");
             break;
         case XCPT_FLOAT_OVERFLOW:
             printf("got XCPT_FLOAT_OVERFLOW\n");
             break;
         case XCPT_FLOAT_STACK_CHECK:
             printf("got XCPT_FLOAT_STACK_CHECK\n");
             break;
         case XCPT_FLOAT_UNDERFLOW:
             printf("got XCPT_FLOAT_UNDERFLOW\n");
             break;
     }
 #endif

     switch(p1->ExceptionNum) {
         case XCPT_FLOAT_DENORMAL_OPERAND:
         case XCPT_FLOAT_DIVIDE_BY_ZERO:
         case XCPT_FLOAT_INEXACT_RESULT:
         case XCPT_FLOAT_INVALID_OPERATION:
         case XCPT_FLOAT_OVERFLOW:
         case XCPT_FLOAT_STACK_CHECK:
         case XCPT_FLOAT_UNDERFLOW:
         {
             unsigned cw = p3->ctx_env[0];
             if ((cw & MCW_EM) != MCW_EM) {
                 /* Mask out all floating point exceptions */
                 p3->ctx_env[0] |= MCW_EM;
                 /* Following two lines set precision to 53 bit mantissa.  See jsnum.c */
                 p3->ctx_env[0] &= ~MCW_PC;
                 p3->ctx_env[0] |= PC_53;
                 return XCPT_CONTINUE_EXECUTION;
             }
         }
     }
     return XCPT_CONTINUE_SEARCH;
 }

 PR_IMPLEMENT(void)
 PR_OS2_SetFloatExcpHandler(EXCEPTIONREGISTRATIONRECORD* excpreg)
 {
     /* setup the exception handler for the thread */
     APIRET rv;
     excpreg->ExceptionHandler = OS2_FloatExcpHandler;
     excpreg->prev_structure = NULL;
     rv = DosSetExceptionHandler(excpreg);
     PR_ASSERT(rv == NO_ERROR);
 }

 PR_IMPLEMENT(void)
 PR_OS2_UnsetFloatExcpHandler(EXCEPTIONREGISTRATIONRECORD* excpreg)
 {
     /* unset exception handler */
     APIRET rv = DosUnsetExceptionHandler(excpreg);
     PR_ASSERT(rv == NO_ERROR);
 }

 PRStatus
 _PR_MD_INIT_THREAD(PRThread *thread)
 {
    APIRET rv;

    if (thread->flags & (_PR_PRIMORDIAL | _PR_ATTACHED)) {
       _pr_SetThreadMDHandle(thread);
    }

    /* Create the blocking IO semaphore */
    rv = DosCreateEventSem(NULL, &(thread->md.blocked_sema), 0, 0);
    return (rv == NO_ERROR) ? PR_SUCCESS : PR_FAILURE;
 }

 typedef struct param_store
 {
     void (*start)(void *);
     PRThread* thread;
 } PARAMSTORE;

 /* This is a small intermediate function that sets/unsets the exception
    handler before calling the initial thread function */
 static void
 ExcpStartFunc(void* arg)
 {
     EXCEPTIONREGISTRATIONRECORD excpreg;
     PARAMSTORE params, *pParams = arg;

     PR_OS2_SetFloatExcpHandler(&excpreg);

     params = *pParams;
     PR_Free(pParams);
     params.start(params.thread);

     PR_OS2_UnsetFloatExcpHandler(&excpreg);
 }

 PRStatus
 _PR_MD_CREATE_THREAD(PRThread *thread,
                   void (*start)(void *),
                   PRThreadPriority priority,
                   PRThreadScope scope,
                   PRThreadState state,
                   PRUint32 stackSize)
 {
     PARAMSTORE* params = PR_Malloc(sizeof(PARAMSTORE));
     params->start = start;
     params->thread = thread;
     thread->md.handle = thread->id = (TID) _beginthread(ExcpStartFunc,
                                                         NULL,
                                                         thread->stack->stackSize,
                                                         params);
     if(thread->md.handle == -1) {
         return PR_FAILURE;
     }

     /*
      * On OS/2, a thread is created with a thread priority of
      * THREAD_PRIORITY_NORMAL
      */

     if (priority != PR_PRIORITY_NORMAL) {
         _PR_MD_SET_PRIORITY(&(thread->md), priority);
     }

     return PR_SUCCESS;
 }

 void
 _PR_MD_YIELD(void)
 {
     /* Isn't there some problem with DosSleep(0) on OS/2? */
     DosSleep(0);
 }

 void
 _PR_MD_SET_PRIORITY(_MDThread *thread, PRThreadPriority newPri)
 {
     int nativePri = PRTYC_NOCHANGE;
     BOOL rv;

     if (newPri < PR_PRIORITY_FIRST) {
         newPri = PR_PRIORITY_FIRST;
     } else if (newPri > PR_PRIORITY_LAST) {
         newPri = PR_PRIORITY_LAST;
     }
     switch (newPri) {
         case PR_PRIORITY_LOW:
         case PR_PRIORITY_NORMAL:
             nativePri = PRTYC_REGULAR;
             break;
         case PR_PRIORITY_HIGH:
             nativePri = PRTYC_FOREGROUNDSERVER;
             break;
         case PR_PRIORITY_URGENT:
             nativePri = PRTYC_TIMECRITICAL;
     }
     rv = DosSetPriority(PRTYS_THREAD, nativePri, 0, thread->handle);
     PR_ASSERT(rv == NO_ERROR);
     if (rv != NO_ERROR) {
         PR_LOG(_pr_thread_lm, PR_LOG_MIN,
                 ("PR_SetThreadPriority: can't set thread priority\n"));
     }
     return;
 }

 void
 _PR_MD_CLEAN_THREAD(PRThread *thread)
 {
     APIRET rv;

     if (thread->md.blocked_sema) {
         rv = DosCloseEventSem(thread->md.blocked_sema);
         PR_ASSERT(rv == NO_ERROR);
         thread->md.blocked_sema = 0;
     }

     if (thread->md.handle) {
         thread->md.handle = 0;
     }
 }

 void
 _PR_MD_EXIT_THREAD(PRThread *thread)
 {
     _PR_MD_CLEAN_THREAD(thread);
     _PR_MD_SET_CURRENT_THREAD(NULL);
 }


 void
 _PR_MD_EXIT(PRIntn status)
 {
     _exit(status);
 }

 #ifdef HAVE_THREAD_AFFINITY
 PR_EXTERN(PRInt32)
 _PR_MD_SETTHREADAFFINITYMASK(PRThread *thread, PRUint32 mask )
 {
    /* Can we do this on OS/2?  Only on SMP versions? */
    PR_ASSERT(!"Not implemented");
    return 0;

  /* This is what windows does:
     int rv;

     rv = SetThreadAffinityMask(thread->md.handle, mask);

     return rv?0:-1;
   */
 }

 PR_EXTERN(PRInt32)
 _PR_MD_GETTHREADAFFINITYMASK(PRThread *thread, PRUint32 *mask)
 {
    /* Can we do this on OS/2?  Only on SMP versions? */
    PR_ASSERT(!"Not implemented");
    return 0;

  /* This is what windows does:
     PRInt32 rv, system_mask;

     rv = GetProcessAffinityMask(GetCurrentProcess(), mask, &system_mask);

     return rv?0:-1;
   */
 }
 #endif /* HAVE_THREAD_AFFINITY */

 void
 _PR_MD_SUSPEND_CPU(_PRCPU *cpu)
 {
     _PR_MD_SUSPEND_THREAD(cpu->thread);
 }

 void
 _PR_MD_RESUME_CPU(_PRCPU *cpu)
 {
     _PR_MD_RESUME_THREAD(cpu->thread);
 }

 void
 _PR_MD_SUSPEND_THREAD(PRThread *thread)
 {
     if (_PR_IS_NATIVE_THREAD(thread)) {
        APIRET rc;

         /* XXXMB - DosSuspendThread() is not a blocking call; how do we
          * know when the thread is *REALLY* suspended?
          */
        rc = DosSuspendThread(thread->md.handle);
        PR_ASSERT(rc == NO_ERROR);
     }
 }

 void
 _PR_MD_RESUME_THREAD(PRThread *thread)
 {
     if (_PR_IS_NATIVE_THREAD(thread)) {
         DosResumeThread(thread->md.handle);
     }
 }


 PRThread*
 _MD_CURRENT_THREAD(void)
 {
     PRThread *thread;

     thread = _MD_GET_ATTACHED_THREAD();

     if (NULL == thread) {
         thread = _PRI_AttachThread(PR_USER_THREAD, PR_PRIORITY_NORMAL, NULL, 0);
     }

     PR_ASSERT(thread != NULL);
     return thread;
 }
	/* -- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -- */
	/* *** BEGIN LICENSE BLOCK ***
	* Version: MPL 1.1/GPL 2.0/LGPL 2.1
	*
	* The contents of this file are subject to the Mozilla Public License Version
	* 1.1 (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	* http://www.mozilla.org/MPL/
	*
	* Software distributed under the License is distributed on an "AS IS" basis,
	* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
	* for the specific language governing rights and limitations under the
	* License.
	*
	* The Original Code is the Netscape Portable Runtime (NSPR).
	*
	* The Initial Developer of the Original Code is
	* Netscape Communications Corporation.
	* Portions created by the Initial Developer are Copyright (C) 1998-2000
	* the Initial Developer. All Rights Reserved.
	*
	* Contributor(s):
	*
	* Alternatively, the contents of this file may be used under the terms of
	* either the GNU General Public License Version 2 or later (the "GPL"), or
	* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
	* in which case the provisions of the GPL or the LGPL are applicable instead
	* of those above. If you wish to allow use of your version of this file only
	* under the terms of either the GPL or the LGPL, and not to allow others to
	* use your version of this file under the terms of the MPL, indicate your
	* decision by deleting the provisions above and replace them with the notice
	* and other provisions required by the GPL or the LGPL. If you do not delete
	* the provisions above, a recipient may use your version of this file under
	* the terms of any one of the MPL, the GPL or the LGPL.
	*
	* *** END LICENSE BLOCK *** */

	#include "primpl.h"
	#include <process.h> /* for _beginthread() */
	#include <signal.h>
	#include <float.h>

	/* --- globals ------------------------------------------------ */
	_NSPR_TLS* pThreadLocalStorage = 0;
	_PRInterruptTable _pr_interruptTable[] = { { 0 } };
	APIRET (* APIENTRY QueryThreadContext)(TID, ULONG, PCONTEXTRECORD);

	void
	_PR_MD_ENSURE_TLS(void)
	{
	if(!pThreadLocalStorage)
	{
	/* Allocate thread local storage (TLS). Note, that only 32 bytes can
	* be allocated at a time.
	*/
	int rc = DosAllocThreadLocalMemory(sizeof(_NSPR_TLS) / 4, (PULONG*)&pThreadLocalStorage);
	PR_ASSERT(rc == NO_ERROR);
	memset(pThreadLocalStorage, 0, sizeof(_NSPR_TLS));
	}
	}

	void
	_PR_MD_EARLY_INIT()
	{
	HMODULE hmod;

	if (DosLoadModule(NULL, 0, "DOSCALL1", &hmod) == 0)
	DosQueryProcAddr(hmod, 877, "DOSQUERYTHREADCONTEXT",
	(PFN *)&QueryThreadContext);
	}

	static void
	_pr_SetThreadMDHandle(PRThread *thread)
	{
	PTIB ptib;
	PPIB ppib;
	PRUword rc;

	rc = DosGetInfoBlocks(&ptib, &ppib);

	thread->md.handle = ptib->tib_ptib2->tib2_ultid;
	}

	/* On OS/2, some system function calls seem to change the FPU control word,
	* such that we crash with a floating underflow exception. The FIX_FPU() call
	* in jsnum.c does not always work, as sometimes FIX_FPU() is called BEFORE the
	* OS/2 system call that horks the FPU control word. So, we set an exception
	* handler that covers any floating point exceptions and resets the FPU CW to
	* the required value.
	*/
	static ULONG
	_System OS2_FloatExcpHandler(PEXCEPTIONREPORTRECORD p1,
	PEXCEPTIONREGISTRATIONRECORD p2,
	PCONTEXTRECORD p3,
	PVOID pv)
	{
	#ifdef DEBUG_pedemonte
	printf("Entering exception handler; ExceptionNum = %x\n", p1->ExceptionNum);
	switch(p1->ExceptionNum) {
	case XCPT_FLOAT_DENORMAL_OPERAND:
	printf("got XCPT_FLOAT_DENORMAL_OPERAND\n");
	break;
	case XCPT_FLOAT_DIVIDE_BY_ZERO:
	printf("got XCPT_FLOAT_DIVIDE_BY_ZERO\n");
	break;
	case XCPT_FLOAT_INEXACT_RESULT:
	printf("got XCPT_FLOAT_INEXACT_RESULT\n");
	break;
	case XCPT_FLOAT_INVALID_OPERATION:
	printf("got XCPT_FLOAT_INVALID_OPERATION\n");
	break;
	case XCPT_FLOAT_OVERFLOW:
	printf("got XCPT_FLOAT_OVERFLOW\n");
	break;
	case XCPT_FLOAT_STACK_CHECK:
	printf("got XCPT_FLOAT_STACK_CHECK\n");
	break;
	case XCPT_FLOAT_UNDERFLOW:
	printf("got XCPT_FLOAT_UNDERFLOW\n");
	break;
	}
	#endif

	switch(p1->ExceptionNum) {
	case XCPT_FLOAT_DENORMAL_OPERAND:
	case XCPT_FLOAT_DIVIDE_BY_ZERO:
	case XCPT_FLOAT_INEXACT_RESULT:
	case XCPT_FLOAT_INVALID_OPERATION:
	case XCPT_FLOAT_OVERFLOW:
	case XCPT_FLOAT_STACK_CHECK:
	case XCPT_FLOAT_UNDERFLOW:
	{
	unsigned cw = p3->ctx_env[0];
	if ((cw & MCW_EM) != MCW_EM) {
	/* Mask out all floating point exceptions */
	p3->ctx_env[0] \|= MCW_EM;
	/* Following two lines set precision to 53 bit mantissa. See jsnum.c */
	p3->ctx_env[0] &= ~MCW_PC;
	p3->ctx_env[0] \|= PC_53;
	return XCPT_CONTINUE_EXECUTION;
	}
	}
	}
	return XCPT_CONTINUE_SEARCH;
	}

	PR_IMPLEMENT(void)
	PR_OS2_SetFloatExcpHandler(EXCEPTIONREGISTRATIONRECORD* excpreg)
	{
	/* setup the exception handler for the thread */
	APIRET rv;
	excpreg->ExceptionHandler = OS2_FloatExcpHandler;
	excpreg->prev_structure = NULL;
	rv = DosSetExceptionHandler(excpreg);
	PR_ASSERT(rv == NO_ERROR);
	}

	PR_IMPLEMENT(void)
	PR_OS2_UnsetFloatExcpHandler(EXCEPTIONREGISTRATIONRECORD* excpreg)
	{
	/* unset exception handler */
	APIRET rv = DosUnsetExceptionHandler(excpreg);
	PR_ASSERT(rv == NO_ERROR);
	}

	PRStatus
	_PR_MD_INIT_THREAD(PRThread *thread)
	{
	APIRET rv;

	if (thread->flags & (_PR_PRIMORDIAL \| _PR_ATTACHED)) {
	_pr_SetThreadMDHandle(thread);
	}

	/* Create the blocking IO semaphore */
	rv = DosCreateEventSem(NULL, &(thread->md.blocked_sema), 0, 0);
	return (rv == NO_ERROR) ? PR_SUCCESS : PR_FAILURE;
	}

	typedef struct param_store
	{
	void (start)(void );
	PRThread* thread;
	} PARAMSTORE;

	/* This is a small intermediate function that sets/unsets the exception
	handler before calling the initial thread function */
	static void
	ExcpStartFunc(void* arg)
	{
	EXCEPTIONREGISTRATIONRECORD excpreg;
	PARAMSTORE params, *pParams = arg;

	PR_OS2_SetFloatExcpHandler(&excpreg);

	params = *pParams;
	PR_Free(pParams);
	params.start(params.thread);

	PR_OS2_UnsetFloatExcpHandler(&excpreg);
	}

	PRStatus
	_PR_MD_CREATE_THREAD(PRThread *thread,
	void (start)(void ),
	PRThreadPriority priority,
	PRThreadScope scope,
	PRThreadState state,
	PRUint32 stackSize)
	{
	PARAMSTORE* params = PR_Malloc(sizeof(PARAMSTORE));
	params->start = start;
	params->thread = thread;
	thread->md.handle = thread->id = (TID) _beginthread(ExcpStartFunc,
	NULL,
	thread->stack->stackSize,
	params);
	if(thread->md.handle == -1) {
	return PR_FAILURE;
	}

	/*
	* On OS/2, a thread is created with a thread priority of
	* THREAD_PRIORITY_NORMAL
	*/

	if (priority != PR_PRIORITY_NORMAL) {
	_PR_MD_SET_PRIORITY(&(thread->md), priority);
	}

	return PR_SUCCESS;
	}

	void
	_PR_MD_YIELD(void)
	{
	/* Isn't there some problem with DosSleep(0) on OS/2? */
	DosSleep(0);
	}

	void
	_PR_MD_SET_PRIORITY(_MDThread *thread, PRThreadPriority newPri)
	{
	int nativePri = PRTYC_NOCHANGE;
	BOOL rv;

	if (newPri < PR_PRIORITY_FIRST) {
	newPri = PR_PRIORITY_FIRST;
	} else if (newPri > PR_PRIORITY_LAST) {
	newPri = PR_PRIORITY_LAST;
	}
	switch (newPri) {
	case PR_PRIORITY_LOW:
	case PR_PRIORITY_NORMAL:
	nativePri = PRTYC_REGULAR;
	break;
	case PR_PRIORITY_HIGH:
	nativePri = PRTYC_FOREGROUNDSERVER;
	break;
	case PR_PRIORITY_URGENT:
	nativePri = PRTYC_TIMECRITICAL;
	}
	rv = DosSetPriority(PRTYS_THREAD, nativePri, 0, thread->handle);
	PR_ASSERT(rv == NO_ERROR);
	if (rv != NO_ERROR) {
	PR_LOG(_pr_thread_lm, PR_LOG_MIN,
	("PR_SetThreadPriority: can't set thread priority\n"));
	}
	return;
	}

	void
	_PR_MD_CLEAN_THREAD(PRThread *thread)
	{
	APIRET rv;

	if (thread->md.blocked_sema) {
	rv = DosCloseEventSem(thread->md.blocked_sema);
	PR_ASSERT(rv == NO_ERROR);
	thread->md.blocked_sema = 0;
	}

	if (thread->md.handle) {
	thread->md.handle = 0;
	}
	}

	void
	_PR_MD_EXIT_THREAD(PRThread *thread)
	{
	_PR_MD_CLEAN_THREAD(thread);
	_PR_MD_SET_CURRENT_THREAD(NULL);
	}


	void
	_PR_MD_EXIT(PRIntn status)
	{
	_exit(status);
	}

	#ifdef HAVE_THREAD_AFFINITY
	PR_EXTERN(PRInt32)
	_PR_MD_SETTHREADAFFINITYMASK(PRThread *thread, PRUint32 mask )
	{
	/* Can we do this on OS/2? Only on SMP versions? */
	PR_ASSERT(!"Not implemented");
	return 0;

	/* This is what windows does:
	int rv;

	rv = SetThreadAffinityMask(thread->md.handle, mask);

	return rv?0:-1;
	*/
	}

	PR_EXTERN(PRInt32)
	_PR_MD_GETTHREADAFFINITYMASK(PRThread thread, PRUint32 mask)
	{
	/* Can we do this on OS/2? Only on SMP versions? */
	PR_ASSERT(!"Not implemented");
	return 0;

	/* This is what windows does:
	PRInt32 rv, system_mask;

	rv = GetProcessAffinityMask(GetCurrentProcess(), mask, &system_mask);

	return rv?0:-1;
	*/
	}
	#endif /* HAVE_THREAD_AFFINITY */

	void
	_PR_MD_SUSPEND_CPU(_PRCPU *cpu)
	{
	_PR_MD_SUSPEND_THREAD(cpu->thread);
	}

	void
	_PR_MD_RESUME_CPU(_PRCPU *cpu)
	{
	_PR_MD_RESUME_THREAD(cpu->thread);
	}

	void
	_PR_MD_SUSPEND_THREAD(PRThread *thread)
	{
	if (_PR_IS_NATIVE_THREAD(thread)) {
	APIRET rc;

	/* XXXMB - DosSuspendThread() is not a blocking call; how do we
	* know when the thread is REALLY suspended?
	*/
	rc = DosSuspendThread(thread->md.handle);
	PR_ASSERT(rc == NO_ERROR);
	}
	}

	void
	_PR_MD_RESUME_THREAD(PRThread *thread)
	{
	if (_PR_IS_NATIVE_THREAD(thread)) {
	DosResumeThread(thread->md.handle);
	}
	}


	PRThread*
	_MD_CURRENT_THREAD(void)
	{
	PRThread *thread;

	thread = _MD_GET_ATTACHED_THREAD();

	if (NULL == thread) {
	thread = _PRI_AttachThread(PR_USER_THREAD, PR_PRIORITY_NORMAL, NULL, 0);
	}

	PR_ASSERT(thread != NULL);
	return thread;
	}