Initial commit of OpenSPARC T2 architecture model.

[OpenSPARC-T2-SAM] / sam-t2 / sam / system / util / include / atomic.h

/*
* ========== Copyright Header Begin ==========================================
* 
* OpenSPARC T2 Processor File: atomic.h
* Copyright (c) 2006 Sun Microsystems, Inc.  All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES.
* 
* The above named program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License version 2 as published by the Free Software Foundation.
* 
* The above named program is distributed in the hope that it will be 
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* General Public License for more details.
* 
* You should have received a copy of the GNU General Public
* License along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
* 
* ========== Copyright Header End ============================================
*/
/*
* "atomic.h"
*
*      atomic arithmetic and logical ops
*              all atomic ops return the PREVIOUS value.
*
*      barrier sync using atomics and spinloops,
*              for when #workerthreads <= #hostcpus only, otherwise 
*                      performance will be _severly_ degraded...
*              and requires TSO memory as currently coded w/o any membars.
*
*/
#ifndef _ATOMIC_H
#define _ATOMIC_H

#ifdef __cplusplus
extern "C" {
#endif

extern int32_t atomic_add_32 (volatile int32_t * variable, const int32_t value);
extern int32_t atomic_sub_32 (volatile int32_t * variable, const int32_t value);
extern int32_t atomic_and_32 (volatile int32_t * variable, const int32_t value);
extern int32_t atomic_or_32  (volatile int32_t * variable, const int32_t value);
extern int32_t atomic_xor_32 (volatile int32_t * variable, const int32_t value);



inline int32_t atomic_barrier (volatile int32_t * numThreads,
                              volatile int32_t * doneCount,
                              volatile int32_t * doneLock,
                              volatile int32_t * returnVal,
                              volatile int32_t * tempVal)
{
   register int32_t tmp = *doneLock;           // fetch on entry <------------#
   register int32_t NTm1 = *numThreads-1;

   if (atomic_add_32 (doneCount, 1) < NTm1) {  // early arrivals

       while (*doneLock == tmp) ;                      // spin until flip <---#

   } else {                                    // last arrival

       *doneCount = 0;                                 // resets
       *tempVal = *returnVal;                          // inspects
       *doneLock = !tmp;                               // flips <-------------#
   }

   return *tempVal;            // everybody gets identical return value.
}



extern int64_t atomic_add_64 (volatile int64_t * variable, const int64_t value);
extern int64_t atomic_sub_64 (volatile int64_t * variable, const int64_t value);
extern int64_t atomic_and_64 (volatile int64_t * variable, const int64_t value);
extern int64_t atomic_or_64  (volatile int64_t * variable, const int64_t value);
extern int64_t atomic_xor_64 (volatile int64_t * variable, const int64_t value);

#ifdef __cplusplus
}
#endif

#endif/*_ATOMIC_H*/