// NeL - MMORPG Framework <http://dev.ryzom.com/projects/nel/>
// Copyright (C) 2010  Winch Gate Property Limited
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "stdmisc.h"

#include "nel/misc/fast_mem.h"
#include "nel/misc/system_info.h"


namespace NLMISC
{

#if defined(NL_OS_WINDOWS) && !defined(NL_NO_ASM)


// ***************************************************************************
void		*CFastMem::memcpySSE(void *dest, const void *src, size_t nbytes)
{
	_asm
	{
			mov esi, src
			mov edi, dest
			mov ebx, nbytes

			// edx takes number of bytes%64
			mov	edx, ebx
			and edx, 63

			// ebx takes number of bytes/64
			shr	ebx, 6
			jz	byteCopy


	loop4k: // flush 4k into temporary buffer
			push esi
			mov ecx, ebx
			// copy per block of 64 bytes. Must not override 64*64= 4096 bytes.
			cmp ecx, 64
			jle	skipMiniMize
			mov	ecx, 64
	skipMiniMize:
			// eax takes the number of 64bytes packet for this block.
			mov eax, ecx

	loopMemToL1:
			prefetchnta 64[ESI] // Prefetch next loop, non-temporal
			prefetchnta 96[ESI]

			movq mm1,  0[ESI] // Read in source data
			movq mm2,  8[ESI]
			movq mm3, 16[ESI]
			movq mm4, 24[ESI]
			movq mm5, 32[ESI]
			movq mm6, 40[ESI]
			movq mm7, 48[ESI]
			movq mm0, 56[ESI]

			add esi, 64
			dec ecx
			jnz loopMemToL1

			pop esi // Now copy from L1 to system memory
			mov ecx, eax

	loopL1ToMem:
			movq mm1, 0[ESI] // Read in source data from L1
			movq mm2, 8[ESI]
			movq mm3, 16[ESI]
			movq mm4, 24[ESI]
			movq mm5, 32[ESI]
			movq mm6, 40[ESI]
			movq mm7, 48[ESI]
			movq mm0, 56[ESI]

			movntq 0[EDI], mm1 // Non-temporal stores
			movntq 8[EDI], mm2
			movntq 16[EDI], mm3
			movntq 24[EDI], mm4
			movntq 32[EDI], mm5
			movntq 40[EDI], mm6
			movntq 48[EDI], mm7
			movntq 56[EDI], mm0

			add esi, 64
			add edi, 64
			dec ecx
			jnz loopL1ToMem

			// Do next 4k block
			sub ebx, eax
			jnz loop4k

			emms

	byteCopy:
			// Do last bytes with std cpy
			mov	ecx, edx
			rep movsb
	}
	return dest;
}

// ***************************************************************************
void		CFastMem::precacheSSE(const void *src, uint nbytes)
{
	_asm
	{
			mov esi, src
			mov ecx, nbytes
			// 64 bytes per pass
			shr ecx, 6
			jz endLabel

	loopMemToL1:
			prefetchnta 64[ESI] // Prefetch next loop, non-temporal
			prefetchnta 96[ESI]

			movq mm1,  0[ESI] // Read in source data
			movq mm2,  8[ESI]
			movq mm3, 16[ESI]
			movq mm4, 24[ESI]
			movq mm5, 32[ESI]
			movq mm6, 40[ESI]
			movq mm7, 48[ESI]
			movq mm0, 56[ESI]

			add esi, 64
			dec ecx
			jnz loopMemToL1

			emms

	endLabel:
	}
}

// ***************************************************************************
void		CFastMem::precacheMMX(const void *src, uint nbytes)
{
	_asm
	{
			mov esi, src
			mov ecx, nbytes
			// 64 bytes per pass
			shr ecx, 6
			jz endLabel

	loopMemToL1:
			movq mm1,  0[ESI] // Read in source data
			movq mm2,  8[ESI]
			movq mm3, 16[ESI]
			movq mm4, 24[ESI]
			movq mm5, 32[ESI]
			movq mm6, 40[ESI]
			movq mm7, 48[ESI]
			movq mm0, 56[ESI]

			add esi, 64
			dec ecx
			jnz loopMemToL1

			emms

	endLabel:
	}
}


// ***************************************************************************
void		CFastMem::precache(const void *src, uint nbytes)
{
	if(NLMISC::CSystemInfo::hasSSE())
		precacheSSE(src, nbytes);
	else if(NLMISC::CSystemInfo::hasMMX())
		precacheMMX(src, nbytes);
}


#else


// ***************************************************************************
void		*CFastMem::memcpySSE(void *dst, const void *src, size_t nbytes)
{
	// Use std memcpy.
	return memcpy(dst, src, nbytes);
}
void		CFastMem::precacheSSE(const void *src, uint nbytes)
{
	// no-op.
}
void		CFastMem::precacheMMX(const void *src, uint nbytes)
{
	// no-op.
}
void		CFastMem::precache(const void *src, uint nbytes)
{
	// no-op.
}

#endif

typedef void  *(*memcpyPtr)(void *dts, const void *src, size_t nbytes);

static memcpyPtr findBestmemcpy ()
{
#if defined(NL_OS_WINDOWS) && !defined(NL_NO_ASM)
	if (CSystemInfo::hasSSE ())
		return CFastMem::memcpySSE;
	else
		return ::memcpy;
#else // NL_OS_WINDOWS
	return ::memcpy;
#endif // NL_OS_WINDOWS
}

void  *(*CFastMem::memcpy)(void *dts, const void *src, size_t nbytes) = findBestmemcpy ();

} // NLMISC