gcc_itsx.h

/*
    Copyright 2005-2016 Intel Corporation.  All Rights Reserved.

    This file is part of Threading Building Blocks. Threading Building Blocks 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.  Threading Building Blocks 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 Threading Building Blocks; if not, write to the
    Free Software Foundation, Inc.,  51 Franklin St,  Fifth Floor,  Boston,  MA 02110-1301 USA

    As a special exception,  you may use this file  as part of a free software library without
    restriction.  Specifically,  if other files instantiate templates  or use macros or inline
    functions from this file, or you compile this file and link it with other files to produce
    an executable,  this file does not by itself cause the resulting executable to be covered
    by the GNU General Public License. This exception does not however invalidate any other
    reasons why the executable file might be covered by the GNU General Public License.
*/

#if !defined(__TBB_machine_H) || defined(__TBB_machine_gcc_itsx_H)
#error Do not #include this internal file directly; use public TBB headers instead.
#endif

#define __TBB_machine_gcc_itsx_H

#define __TBB_OP_XACQUIRE 0xF2
#define __TBB_OP_XRELEASE 0xF3
#define __TBB_OP_LOCK     0xF0

#define __TBB_STRINGIZE_INTERNAL(arg) #arg
#define __TBB_STRINGIZE(arg) __TBB_STRINGIZE_INTERNAL(arg)

#ifdef __TBB_x86_64
#define __TBB_r_out "=r"
#else
#define __TBB_r_out "=q"
#endif

inline static uint8_t __TBB_machine_try_lock_elided( volatile uint8_t* lk )
{
    uint8_t value = 1;
    __asm__ volatile (".byte " __TBB_STRINGIZE(__TBB_OP_XACQUIRE)"; lock; xchgb %0, %1;"
                      : __TBB_r_out(value), "=m"(*lk)  : "0"(value), "m"(*lk) : "memory" );
    return uint8_t(value^1);
}

inline static void __TBB_machine_try_lock_elided_cancel()
{
    // 'pause' instruction aborts HLE/RTM transactions
    __asm__ volatile ("pause\n" : : : "memory" );
}

inline static void __TBB_machine_unlock_elided( volatile uint8_t* lk )
{
    __asm__ volatile (".byte " __TBB_STRINGIZE(__TBB_OP_XRELEASE)"; movb $0, %0"
                      : "=m"(*lk) : "m"(*lk) : "memory" );
}

#if __TBB_TSX_INTRINSICS_PRESENT
#include <immintrin.h>

#define __TBB_machine_is_in_transaction _xtest
#define __TBB_machine_begin_transaction _xbegin
#define __TBB_machine_end_transaction   _xend
#define __TBB_machine_transaction_conflict_abort() _xabort(0xff)

#else

inline static bool __TBB_machine_is_in_transaction()
{
    int8_t res = 0;
#if __TBB_x86_32
    __asm__ volatile (".byte 0x0F; .byte 0x01; .byte 0xD6;\n"
                      "setz %0" : "=q"(res) : : "memory" );
#else
    __asm__ volatile (".byte 0x0F; .byte 0x01; .byte 0xD6;\n"
                      "setz %0" : "=r"(res) : : "memory" );
#endif
    return res==0;
}

inline static uint32_t __TBB_machine_begin_transaction()
{
    uint32_t res = ~uint32_t(0);   // success value
    __asm__ volatile ("1: .byte  0xC7; .byte 0xF8;\n"           //  XBEGIN <abort-offset>
                      "   .long  2f-1b-6\n"                     //  2f-1b == difference in addresses of start
                                                                //  of XBEGIN and the MOVL
                                                                //  2f - 1b - 6 == that difference minus the size of the
                                                                //  XBEGIN instruction.  This is the abort offset to
                                                                //  2: below.
                      "    jmp   3f\n"                          //  success (leave -1 in res)
                      "2:  movl  %%eax,%0\n"                    //  store failure code in res
                      "3:"
                      :"=r"(res):"0"(res):"memory","%eax");
    return res;
}

inline static void __TBB_machine_end_transaction()
{
    __asm__ volatile (".byte 0x0F; .byte 0x01; .byte 0xD5" :::"memory");   // XEND
}

/*
 * aborts with code 0xFF (lock already held)
 */
inline static void __TBB_machine_transaction_conflict_abort()
{
    __asm__ volatile (".byte 0xC6; .byte 0xF8; .byte 0xFF" :::"memory");
}

#endif /* __TBB_TSX_INTRINSICS_PRESENT */