/*   $Source: /var/local/cvs/gasnet/gasnet_asm.h,v $
 *     $Date: 2007/10/26 01:13:58 $
 * $Revision: 1.122 $
 * Description: GASNet header for semi-portable inline asm support
 * Copyright 2002, Dan Bonachea <bonachea@cs.berkeley.edu>
 * Terms of use are as specified in license.txt
 */

#if !defined(_IN_GASNET_TOOLS_H) && !defined(_IN_GASNET_H) && !defined(_IN_CONFIGURE)
  #error This file is not meant to be included directly- clients should include gasnet.h or gasnet_tools.h
#endif

#ifndef _GASNET_ASM_H
#define _GASNET_ASM_H

#include "portable_platform.h"

#define GASNETI_ASM_AVAILABLE 1
#if PLATFORM_COMPILER_GNU || PLATFORM_COMPILER_INTEL || PLATFORM_COMPILER_PATHSCALE || \
    PLATFORM_COMPILER_TINY 
  #define GASNETI_ASM(mnemonic) __asm__ __volatile__ (mnemonic : : : "memory")
#elif PLATFORM_COMPILER_PGI 
  /* Some definitions:
   *
   * GASNETI_PGI_ASM_GNU 
   *   Compiler accepts GNU-style asm() such as asm ("code" : "r" (out) : "r" (in) : "memory");
   *   While pgcc 6.1-1 and pgCC 6.2-2 include full GNU-style asm() support, our inability to
   *   reliably identify either of those version numbers leads to higher actual cut-offs in
   *   some cases.
   *   Implies PLATFORM_COMPILER_PGI
   *
   * GASNETI_PGI_ASM_THREADSAFE
   *   Compiler does not suffer from "tpr 3852" in which "gratuitous" register reloads after
   *   an inline asm() renders the GNU-style asm() support unsuitable for GASNet atomics.
   *   Implies PLATFORM_COMPILER_PGI && GASNETI_PGI_ASM_GNU
   *
   * GASNETI_PGI_ASM_X86_A
   *   Compiler does not suffer from "tpr 3843" in which use of the "A" constraint in a
   *   GNU-style asm() would crash the compiler.  This is applicable only to 32-bit targets,
   *   and the value of this symbol on 64-bit targets is undefined.
   *   Implies PLATFORM_COMPILER_PGI && GASNETI_PGI_ASM_GNU
   *
   * GASNETI_PGI_ASM_BUG1754
   *   Compiler suffers from "tpr 3936" in which promotion of a char variable previously used
   *   as an output of an extended asm() does not zero out bits 8 and higher.  Experiments show
   *   this was probably resolved in 6.2-4.  However, the Portland Group documents this tpr as
   *   resolved in 6.2-5.  So, we use the vendor's more conservative value.
   *   Implies PLATFORM_COMPILER_PGI && GASNETI_PGI_ASM_GNU
   *
   * GASNETI_PGI_ASM_BUG2149
   *   Compiler suffers from "tpr 4336" in which extended asm() register outputs are "lost"
   *   when the "register" qualifier is applied to the output variable.
   *
   * See GASNet bug 1621 (http://upc-bugs.lbl.gov/bugzilla/show_bug.cgi?id=1621) for more
   * info on the bugs indicated by GASNETI_PGI_ASM_THREADSAFE and GASNETI_PGI_ASM_X86_A.
   *
   * See GASNet bugs 1751 and 1753 for discussion related to the difficulty with versioning
   * of the Portland Group compilers.  See also PGI "tpr 3791" and discussion thread
   * http://www.pgroup.com/userforum/viewtopic.php?t=466
   *
   * See GASNet bug 1754 for discussion related to the BUG1754 problem and its symptoms.
   * See also PGI "tpr 3936".
   *
   * See GASNet bug 2149 for discussion related to the BUG2149 problem and its symptoms.
   * See also PGI "tpr 4336".
   */
  #if (PLATFORM_COMPILER_PGI_C && PLATFORM_COMPILER_VERSION_GE(6,1,1)) || \
      (PLATFORM_COMPILER_PGI_CXX && PLATFORM_COMPILER_VERSION_GE(6,2,2))
    #define GASNETI_PGI_ASM_GNU 1
    #define GASNETI_ASM(mnemonic) __asm__ __volatile__ (mnemonic : : : "memory")
  #else /* note this requires compiler flag -Masmkeyword */
    #define GASNETI_ASM(mnemonic) asm(mnemonic)
  #endif
  #if PLATFORM_COMPILER_VERSION_GE(6,2,2)
    #define GASNETI_PGI_ASM_THREADSAFE 1
    #define GASNETI_PGI_ASM_X86_A 1
  #endif
  #if PLATFORM_COMPILER_VERSION_LT(6,2,5)
    #define GASNETI_PGI_ASM_BUG1754 1
  #endif
  #if PLATFORM_COMPILER_VERSION_GE(7,1,0) /* XXX: need end of range once fixed */
    #define GASNETI_PGI_ASM_BUG2149 1
  #endif
  #define GASNETI_ASM_SPECIAL(mnemonic) asm(mnemonic)
#elif PLATFORM_COMPILER_COMPAQ
  #include <c_asm.h>
  #define GASNETI_ASM(mnemonic) asm(mnemonic)
#elif PLATFORM_COMPILER_SUN 
  #ifdef __cplusplus 
    #if PLATFORM_OS_LINUX
      #define GASNETI_ASM(mnemonic)  asm(mnemonic)
    #else /* Sun C++ on Solaris lacks inline assembly support (man inline) */
      #define GASNETI_ASM(mnemonic)  ERROR_NO_INLINE_ASSEMBLY_AVAIL /* not supported or used */
      #undef GASNETI_ASM_AVAILABLE
    #endif
  #else /* Sun C */
    #define GASNETI_ASM(mnemonic)  __asm(mnemonic)
  #endif
#elif PLATFORM_COMPILER_NEC 
  #define GASNETI_ASM(mnemonic)  asm(mnemonic)
#elif PLATFORM_COMPILER_HP_C
  #define GASNETI_ASM(mnemonic)  _asm(mnemonic)
#elif PLATFORM_COMPILER_SGI || PLATFORM_COMPILER_HP_CXX || PLATFORM_COMPILER_XLC || \
      PLATFORM_COMPILER_CRAY || PLATFORM_COMPILER_MTA || PLATFORM_COMPILER_LCC
  /* platforms where inline assembly not supported or used */
  #define GASNETI_ASM(mnemonic)  ERROR_NO_INLINE_ASSEMBLY_AVAIL 
  #undef GASNETI_ASM_AVAILABLE
#else
  #error "Don't know how to use inline assembly for your compiler"
#endif

#ifndef GASNETI_ASM_SPECIAL
  #define GASNETI_ASM_SPECIAL GASNETI_ASM
#endif

#endif /* _GASNET_ASM_H */