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// -*- C++ -*-
//
// $Id$
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
//
// The ACE_CDR::swap_X and ACE_CDR::swap_X_array routines are broken
// in 4 cases for optimization:
//
// * AMD64 CPU + gnu g++
// => gcc amd64 inline assembly.
//
// * x86 Pentium CPU + gnu g++
// (ACE_HAS_PENTIUM && __GNUG__)
// => gcc x86 inline assembly.
//
// * x86 Pentium CPU and (_MSC_VER) or BORLAND C++)
// (ACE_HAS_PENTIUM && ( _MSC_VER || __BORLANDC__ )
// => MSC x86 inline assembly.
//
// * 64 bit architecture
// (ACE_SIZEOF_LONG == 8)
// => shift/masks using 64bit words.
//
// * default
// (none of the above)
// => shift/masks using 32bit words.
//
//
// Some things you could find useful to know if you intend to mess
// with this optimizations for swaps:
//
// * MSVC++ don't assume register values are conserved between
// statements. So you can clobber any register you want,
// whenever you want (well not *anyone* really, see manual).
// The MSVC++ optimizer will try to pick different registers
// for the C++ statements sorrounding your asm block, and if
// it's not possible will use the stack.
//
// * If you clobber registers with asm statements in gcc, you
// better do it in an asm-only function, or save/restore them
// before/after in the stack. If not, sorrounding C statements
// could end using the same registers and big-badda-bum (been
// there, done that...). The big-badda-bum could happen *even
// if you specify the clobbered register in your asm's*.
// Even better, use gcc asm syntax for detecting the register
// asigned to a certain variable so you don't have to clobber any
// register directly.
//
ACE_INLINE void
ACE_CDR::swap_2 (const char *orig, char* target)
{
#if (defined(ACE_HAS_PENTIUM) || defined (__amd64__)) && defined(__GNUG__)
unsigned short a =
*reinterpret_cast<const unsigned short*> (orig);
asm( "rolw $8, %0" : "=r" (a) : "0" (a) );
*reinterpret_cast<unsigned short*> (target) = a;
#elif defined (ACE_HAS_PENTIUM) \
&& (defined(_MSC_VER) || defined(__BORLANDC__)) \
&& !defined(ACE_LACKS_INLINE_ASSEMBLY)
__asm mov ebx, orig;
__asm mov ecx, target;
__asm mov ax, [ebx];
__asm rol ax, 8;
__asm mov [ecx], ax;
#else
register ACE_UINT16 usrc = * reinterpret_cast<const ACE_UINT16*> (orig);
register ACE_UINT16* udst = reinterpret_cast<ACE_UINT16*> (target);
*udst = (usrc << 8) | (usrc >> 8);
#endif /* ACE_HAS_PENTIUM */
}
ACE_INLINE void
ACE_CDR::swap_4 (const char* orig, char* target)
{
#if (defined(ACE_HAS_PENTIUM) || defined (__amd64__)) && defined(__GNUG__)
// We have ACE_HAS_PENTIUM, so we know the sizeof's.
register unsigned int j =
*reinterpret_cast<const unsigned int*> (orig);
asm ("bswap %1" : "=r" (j) : "0" (j));
*reinterpret_cast<unsigned int*> (target) = j;
#elif defined(ACE_HAS_PENTIUM) \
&& (defined(_MSC_VER) || defined(__BORLANDC__)) \
&& !defined(ACE_LACKS_INLINE_ASSEMBLY)
__asm mov ebx, orig;
__asm mov ecx, target;
__asm mov eax, [ebx];
__asm bswap eax;
__asm mov [ecx], eax;
#else
register ACE_UINT32 x = * reinterpret_cast<const ACE_UINT32*> (orig);
x = (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);
* reinterpret_cast<ACE_UINT32*> (target) = x;
#endif
}
ACE_INLINE void
ACE_CDR::swap_8 (const char* orig, char* target)
{
#if defined(__amd64__) && defined(__GNUG__)
register unsigned long x =
* reinterpret_cast<const unsigned long*> (orig);
asm ("bswapq %1" : "=r" (x) : "0" (x));
*reinterpret_cast<unsigned long*> (target) = x;
#elif defined(ACE_HAS_PENTIUM) && defined(__GNUG__)
register unsigned int i =
*reinterpret_cast<const unsigned int*> (orig);
register unsigned int j =
*reinterpret_cast<const unsigned int*> (orig + 4);
asm ("bswap %1" : "=r" (i) : "0" (i));
asm ("bswap %1" : "=r" (j) : "0" (j));
*reinterpret_cast<unsigned int*> (target + 4) = i;
*reinterpret_cast<unsigned int*> (target) = j;
#elif defined(ACE_HAS_PENTIUM) \
&& (defined(_MSC_VER) || defined(__BORLANDC__)) \
&& !defined(ACE_LACKS_INLINE_ASSEMBLY)
__asm mov ecx, orig;
__asm mov edx, target;
__asm mov eax, [ecx];
__asm mov ebx, 4[ecx];
__asm bswap eax;
__asm bswap ebx;
__asm mov 4[edx], eax;
__asm mov [edx], ebx;
#elif ACE_SIZEOF_LONG == 8
// 64 bit architecture.
register unsigned long x =
* reinterpret_cast<const unsigned long*> (orig);
register unsigned long x84 = (x & 0x000000ff000000ffUL) << 24;
register unsigned long x73 = (x & 0x0000ff000000ff00UL) << 8;
register unsigned long x62 = (x & 0x00ff000000ff0000UL) >> 8;
register unsigned long x51 = (x & 0xff000000ff000000UL) >> 24;
x = (x84 | x73 | x62 | x51);
x = (x << 32) | (x >> 32);
*reinterpret_cast<unsigned long*> (target) = x;
#else
register ACE_UINT32 x =
* reinterpret_cast<const ACE_UINT32*> (orig);
register ACE_UINT32 y =
* reinterpret_cast<const ACE_UINT32*> (orig + 4);
x = (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);
y = (y << 24) | ((y & 0xff00) << 8) | ((y & 0xff0000) >> 8) | (y >> 24);
* reinterpret_cast<ACE_UINT32*> (target) = y;
* reinterpret_cast<ACE_UINT32*> (target + 4) = x;
#endif
}
ACE_INLINE void
ACE_CDR::swap_16 (const char* orig, char* target)
{
swap_8 (orig + 8, target);
swap_8 (orig, target + 8);
}
ACE_INLINE size_t
ACE_CDR::first_size (size_t minsize)
{
if (minsize == 0)
return ACE_CDR::DEFAULT_BUFSIZE;
size_t newsize = ACE_CDR::DEFAULT_BUFSIZE;
while (newsize < minsize)
{
if (newsize < ACE_CDR::EXP_GROWTH_MAX)
{
// We grow exponentially at the beginning, this is fast and
// reduces the number of allocations.
// Quickly multiply by two using a bit shift. This is
// guaranteed to work since the variable is an unsigned
// integer.
newsize <<= 1;
}
else
{
// but continuing with exponential growth can result in over
// allocations and easily yield an allocation failure.
// So we grow linearly when the buffer is too big.
newsize += ACE_CDR::LINEAR_GROWTH_CHUNK;
}
}
return newsize;
}
ACE_INLINE size_t
ACE_CDR::next_size (size_t minsize)
{
size_t newsize =
ACE_CDR::first_size (minsize);
if (newsize == minsize)
{
// If necessary increment the size
if (newsize < ACE_CDR::EXP_GROWTH_MAX)
// Quickly multiply by two using a bit shift. This is
// guaranteed to work since the variable is an unsigned
// integer.
newsize <<= 1;
else
newsize += ACE_CDR::LINEAR_GROWTH_CHUNK;
}
return newsize;
}
ACE_END_VERSIONED_NAMESPACE_DECL
// ****************************************************************
|
