Optimization Method for memory copy (draft) [2]

References: %defineparamesp124% definesrcparam0 % definedstparam4 % definelenparam8 % unknown: Unknown, [src]; sourcearraymovedi, [dst]; destinationarraymovecx, [len]; numbero

References: %%%%%%definedstparam4% definelenparam8 % defineCACHEBLOCK400h _ fast_memcpy9: pushesi pushedi pushebx movesi, [src]; sourcearray movedi, [dst]; destinationarray movecx, [len]; numbero

Reference:

Global _ fast_memcpy9

% Define param esp + 12 + 4
% Define src param + 0
% Define dst param + 4
% Define len param + 8

% Define CACHEBLOCK 400 h

_ Fast_memcpy9:
Push esi
Push edi
Push ebx

Mov esi, [src]; source array
Mov edi, [dst]; destination array
Mov ecx, [len]; number of QWORDS (8 bytes) assumes len/CACHEBLOCK is an integer
Shr ecx, 3

Lea esi, [esi + ecx * 8]; end of source
Lea edi, [edi + ecx * 8]; end of destination
Neg ecx; use a negative offset as a combo pointer-and-loop-counter

. Mainloop:
Mov eax, CACHEBLOCK/16; note:. prefetchloop is unrolled 2X
Add ecx, CACHEBLOCK; move up to end of block

. Prefetchloop:
Mov ebx, [esi + ecx * 8-64]; read one address in this cache line...
Mov ebx, [esi + ecx * 8-128];... and one in the previous line
Sub ecx, 16; 16 QWORDS = 2 64-byte cache lines
Dec eax
Jnz. prefetchloop

Mov eax, CACHEBLOCK/8

. Writeloop:
Prefetchnta [esi + ecx * 8 + 512]; fetch ahead by 512 bytes

Movq mm0, qword [esi + ecx * 8]
Movq mm1, qword [esi + ecx * 8 + 8]
Movq mm2, qword [esi + ecx * 8 + 16]
Movq mm3, qword [esi + ecx * 8 + 24]
Movq mm4, qword [esi + ecx * 8 + 32]
Movq mm5, qword [esi + ecx * 8 + 40]
Movq mm6, qword [esi + ecx * 8 + 48]
Movq mm7, qword [esi + ecx * 8 + 56]

Movntq qword [edi + ecx * 8], mm0
Movntq qword [edi + ecx * 8 + 8], mm1
Movntq qword [edi + ecx * 8 + 16], mm2
Movntq qword [edi + ecx * 8 + 24], mm3
Movntq qword [edi + ecx * 8 + 32], mm4
Movntq qword [edi + ecx * 8 + 40], mm5
Movntq qword [edi + ecx * 8 + 48], mm6
Movntq qword [edi + ecx * 8 + 56], mm7

Add ecx, 8
Dec eax
Jnz. writeloop

Or ecx, ecx; assumes integer number of cacheblocks
Jnz. mainloop

Sfence; flush write buffer
Emms

Pop ebx
Pop edi
Pop esi

Ret