atomicbase.h

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/***********************************************************************
 * Windows / x86 (Visual C/C++)
 *
 * Implementation Notes:
 *   'xadd' is only available in the 486 series and later, not the 386.
 *   There is no 'xsub' counterpart, you have to negate the operand
 *   and use 'xadd'.  Note the use of the 'lock' prefix to ensure
 *   certain operations occur atomically.
 */
#elif defined (_M_IX86) /* && _M_IX86 > 300 XXX wschildbach: disabled until the build system delivers the correct value */

/* Increment by 1 */
static __inline void
HXAtomicIncUINT32(UINT32* pNum)
{
        // register usage summary:
        //   eax - pointer to the value we're modifying
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
        lock inc  dword ptr [eax]        ; Atomically increment *pNum
    }
}

/* Decrement by 1 */
static __inline void
HXAtomicDecUINT32(UINT32* pNum)
{
        // register usage summary:
        //   eax - pointer to the value we're modifying
    _asm
    {
             mov  eax,  pNum             ; Load the pointer into a register
        lock dec  dword ptr [eax]        ; Atomically decrement *pNum
    }
}

/* Increment by 1 and return new value */
static __inline UINT32
HXAtomicIncRetUINT32(UINT32* pNum)
{
    volatile UINT32 ulRet;     
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, 0x1               ; Load increment amount into a register
        lock xadd dword ptr [eax], ebx   ; Increment *pNum; ebx gets old value
             inc  ebx                    ; Increment old value
             mov  ulRet, ebx             ; Set the return value
    }
    return ulRet;
}

/* Decrement by 1 and return new value */
static __inline UINT32
HXAtomicDecRetUINT32(UINT32* pNum)
{   
    volatile UINT32 ulRet;
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
        // note: we increment by 0xffffffff to decrement by 1
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, 0xffffffff        ; Load decrement amount into a register
        lock xadd dword ptr [eax], ebx   ; Decrement *pNum; ebx gets old value
             dec  ebx                    ; decrement old value
             mov  ulRet, ebx             ; Set the return value
    }
    return ulRet;
}

/* Add n */
static __inline void
HXAtomicAddUINT32(UINT32* pNum, UINT32 ulNum)
{
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, ulNum             ; Load increment amount into a register
        lock add  dword ptr [eax], ebx   ; Increment *pNum by ulNum
    }
}

/* Subtract n */
static __inline void
HXAtomicSubUINT32(UINT32* pNum, UINT32 ulNum)
{
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, ulNum             ; Load increment amount into a register
        lock sub  dword ptr [eax], ebx   ; Atomically decrement *pNum by ulNum
    }
}

/* Add n and return new value */
static __inline UINT32
HXAtomicAddRetUINT32(UINT32* pNum, UINT32 ulNum)
{
    volatile UINT32 ulRet;
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
        //   ecx - work register #2
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, ulNum             ; Load increment amount into a register
             mov  ecx, ebx               ; copy ebx into ecx
        lock xadd dword ptr [eax], ecx   ; Increment *pNum; ecx gets old value
             add  ecx, ebx               ; Add ulNum to it
             mov  ulRet, ecx             ; save result in ulRet
    }
    return ulRet;
}

/* Subtract n and return new value */
static __inline UINT32
HXAtomicSubRetUINT32(UINT32* pNum, UINT32 ulNum) 
{   
    volatile UINT32 ulRet;
        // register usage summary:
        //   eax - pointer to the value we're modifying
        //   ebx - work register
        //   ecx - work register #2
    _asm
    {
             mov  eax, pNum              ; Load the pointer into a register
             mov  ebx, ulNum             ; Load increment amount into a register
             mov  ecx, 0x0               ; zero out ecx
             sub  ecx, ebx               ; compute -(ulNum), saving in ecx
        lock xadd dword ptr [eax], ecx   ; Decrement *pNum; ecx gets old value
             sub  ecx, ebx               ; subtract ulNum from it
             mov  ulRet, ecx             ; save result in ulRet
    }
    return ulRet;
}

static __inline void HXAtomicIncINT32(INT32* p)              { HXAtomicIncUINT32((UINT32*)p); }
static __inline void HXAtomicDecINT32(INT32* p)              { HXAtomicDecUINT32((UINT32*)p); }
static __inline void HXAtomicAddINT32(INT32* p, INT32 n)     { HXAtomicAddUINT32((UINT32*)p, (UINT32)n); }
static __inline void HXAtomicSubINT32(INT32* p, INT32 n)     { HXAtomicSubUINT32((UINT32*)p, (UINT32)n); }
static __inline INT32 HXAtomicIncRetINT32(INT32* p)          { return HXAtomicIncRetUINT32((UINT32*)p); }
static __inline INT32 HXAtomicDecRetINT32(INT32* p)          { return HXAtomicDecRetUINT32((UINT32*)p); }
static __inline INT32 HXAtomicAddRetINT32(INT32* p, INT32 n) { return HXAtomicAddRetUINT32((UINT32*)p, (UINT32)n); }
static __inline INT32 HXAtomicSubRetINT32(INT32* p, INT32 n) { return HXAtomicSubRetUINT32((UINT32*)p, (UINT32)n); }



/***********************************************************************
 * Intel x86 (gcc) / Unix  -- i486 and higher
 *
 * Implementation Notes:
 *   'xadd' is only available in the 486 series and later, not the 386.
 *   There is no 'xsub' counterpart, you have to negate the operand
 *   and use 'xadd'.  Note the use of the 'lock' prefix to ensure
 *   certain operations occur atomically.
 *
 *   OpenBSD is excluded since the standard assembler on x86 systems
 *   can't handle the xadd instruction.
 *
 */
#elif defined(__GNUC__) && !defined(_OPENBSD) && \
      (__GNUC__>2 || (__GNUC__==2 && __GNUC_MINOR__>=95)) && \
      ( defined (__i486__) || defined (__i586__) || defined (__i686__) || \
        defined (__pentium__) || defined (__pentiumpro__))

/* Increment by 1 */
static __inline__ void
HXAtomicIncUINT32(UINT32* pNum)
{
    __asm__ __volatile__(
        "lock incl (%0);"                // atomically add 1 to *pNum
        : /* no output */
        : "r" (pNum)
        : "cc", "memory"
        );
}

/* Decrement by 1 */
static __inline__ void
HXAtomicDecUINT32(UINT32* pNum)
{
    __asm__ __volatile__(
        "lock decl (%0);"                // atomically add -1 to *pNum
        : /* no output */
        : "r" (pNum)
        : "cc", "memory"
        );
}

/* Increment by 1 and return new value */
static __inline__ UINT32
HXAtomicIncRetUINT32(UINT32* pNum)
{
    volatile UINT32 ulRet;
    __asm__ __volatile__(
        "lock xaddl %0, (%1);"           // atomically add 1 to *pNum
        "     inc   %0;"                 // old value in %0, increment it
        : "=r" (ulRet)
        : "r" (pNum), "0" (0x1)
        : "cc", "memory"
        );
    return ulRet;
}

/* Decrement by 1 and return new value */
static __inline__ UINT32
HXAtomicDecRetUINT32(UINT32* pNum)
{   
    volatile UINT32 ulRet;
    __asm__ __volatile__(
        "lock xaddl %0, (%1);"           // atomically add -1 to *pNum
        "     dec   %0;"                 // old value in %0, decrement it
        : "=r" (ulRet)
        : "r" (pNum), "0" (-1)
        : "cc", "memory"
        );
    return ulRet;
}

/* Add n */
static __inline__ void
HXAtomicAddUINT32(UINT32* pNum, UINT32 ulNum)
{
    __asm__ __volatile__(
        "lock addl %1, (%0);"            // atomically add ulNum to *pNum
        : /* no output */
        : "r" (pNum), "r" (ulNum)
        : "cc", "memory"
        );
}

/* Subtract n */
static __inline__ void
HXAtomicSubUINT32(UINT32* pNum, UINT32 ulNum)
{
    __asm__ __volatile__(
        "lock subl %1, (%0);"            // atomically add ulNum to *pNum
        : /* no output */
        : "r" (pNum), "r" (ulNum)
        : "cc", "memory"
        );
}

/* Add n and return new value */
static __inline__ UINT32
HXAtomicAddRetUINT32(UINT32* pNum, UINT32 ulNum)
{
    volatile UINT32 ulRet;
    __asm__ __volatile__(
        "     mov   %2, %0;"             // copy ulNum into %0
        "lock xaddl %0, (%1);"           // atomically add ulNum to *pNum
        "     add   %2, %0;"             // old value in %0, add ulNum
        : "=r" (ulRet)
        : "r" (pNum), "r" (ulNum), "0" (0)
        : "cc", "memory"
        );
    return ulRet;
}

/* Subtract n and return new value */
static __inline__ UINT32
HXAtomicSubRetUINT32(UINT32* pNum, UINT32 ulNum) 
{   
    volatile UINT32 ulRet;
    __asm__ __volatile__(
        "     sub   %2, %0;"             // negate ulNum, saving in %0
        "lock xaddl %0, (%1);"           // atomically add -(ulNum) to *pNum
        "     sub   %2, %0;"             // old value in %0, subtract ulNum
        : "=r" (ulRet)
        : "r" (pNum), "r" (ulNum), "0" (0)
        : "cc", "memory"
        );
    return ulRet;
}


static __inline__ void HXAtomicIncINT32(INT32* p)              { HXAtomicIncUINT32((UINT32*)p); }
static __inline__ void HXAtomicDecINT32(INT32* p)              { HXAtomicDecUINT32((UINT32*)p); }
static __inline__ void HXAtomicAddINT32(INT32* p, INT32 n)     { HXAtomicAddUINT32((UINT32*)p, (UINT32)n); }
static __inline__ void HXAtomicSubINT32(INT32* p, INT32 n)     { HXAtomicSubUINT32((UINT32*)p, (UINT32)n); }
static __inline__ INT32 HXAtomicIncRetINT32(INT32* p)          { return HXAtomicIncRetUINT32((UINT32*)p); }
static __inline__ INT32 HXAtomicDecRetINT32(INT32* p)          { return HXAtomicDecRetUINT32((UINT32*)p); }
static __inline__ INT32 HXAtomicAddRetINT32(INT32* p, INT32 n) { return HXAtomicAddRetUINT32((UINT32*)p, (UINT32)n); }
static __inline__ INT32 HXAtomicSubRetINT32(INT32* p, INT32 n) { return HXAtomicSubRetUINT32((UINT32*)p, (UINT32)n); }



/***********************************************************************
 * HP-UX / IA64 (Native compiler)
 *
 * Implementation Notes:
 *      A work-in-progress...
 */
#elif defined(_HPUX) && defined(_IA64)

#if defined(__cplusplus)
extern "C" {
#endif
    UINT32 _HXAtomicIncRetUINT32 (UINT32* pNum);
    UINT32 _HXAtomicDecRetUINT32 (UINT32* pNum);
    UINT32 _HXAtomicAddRetUINT32 (UINT32* pNum, UINT32 ulNum);
    UINT32 _HXAtomicSubRetUINT32 (UINT32* pNum, UINT32 ulNum);
#if defined(__cplusplus)
}
#endif

#define HXAtomicIncINT32(p)       _HXAtomicIncRetUINT32((UINT32*)(p))
#define HXAtomicDecINT32(p)       _HXAtomicDecRetUINT32((UINT32*)(p))
#define HXAtomicIncRetINT32(p)    _HXAtomicIncRetUINT32((UINT32*)(p))
#define HXAtomicDecRetINT32(p)    _HXAtomicDecRetUINT32((UINT32*)(p))
#define HXAtomicAddINT32(p,n)     _HXAtomicAddRetUINT32((UINT32*)(p),(INT32)(n))
#define HXAtomicSubINT32(p,n)     _HXAtomicSubRetUINT32((UINT32*)(p),(INT32)(n))
#define HXAtomicAddRetINT32(p,n)  _HXAtomicAddRetUINT32((UINT32*)(p),(INT32)(n))
#define HXAtomicSubRetINT32(p,n)  _HXAtomicSubRetUINT32((UINT32*)(p),(INT32)(n))

#define HXAtomicIncUINT32(p)      _HXAtomicIncRetUINT32((p))
#define HXAtomicDecUINT32(p)      _HXAtomicDecRetUINT32((p))
#define HXAtomicIncRetUINT32(p)   _HXAtomicIncRetUINT32((p))
#define HXAtomicDecRetUINT32(p)   _HXAtomicDecRetUINT32((p))
#define HXAtomicAddUINT32(p,n)    _HXAtomicAddRetUINT32((p),(n))
#define HXAtomicSubUINT32(p,n)    _HXAtomicSubRetUINT32((p),(n))
#define HXAtomicAddRetUINT32(p,n) _HXAtomicAddRetUINT32((p),(n))
#define HXAtomicSubRetUINT32(p,n) _HXAtomicSubRetUINT32((p),(n))



/***********************************************************************
 * Tru64 (OSF1) / Alpha (Native compiler)
 *
 * Implementation Notes:
 *
 * The Alpha CPU provides instructions to load-lock a value,
 * modify it, and attempt to write it back.  If the value has
 * been modified by someone else since the load-lock occured,
 * the write will fail and you can check the status code to
 * know whether you need to retry or not.
 *
 */
#elif defined (__alpha)