DOS ain't dead

MMX moves (Developers)

posted by Laaca , Czech republic, 16.02.2009, 21:20

Do I something wrong or the simple MMX moves are slower than normal 386 moves?
I measured than if I switch on the "block A" it is about 8% slower than if I switch it off.
Both, DS:ESI and ES:EDI are in normal RAM (not VRAM or ROM).

My code:

{DS:ESI = source; ES:EDI = destination; ECX = number of bytes to copy}

{block A}
@mmxloop: movq mm0,ds:[esi];movq es:[edi],mm0
add esi,8;sub ecx,8;add edi,8;cmp ecx,8;jge @mmxloop

{block B}
shr ecx,1;pushf;shr ecx,1;rep movsd;adc ecx,ecx
rep movsw;popf;adc ecx,ecx;rep movsb

---
DOS-u-akbar!

Complete thread:

• MMX moves - Laaca, 16.02.2009, 21:20 (Developers)
  • MMX moves - rr, 16.02.2009, 21:34
  • MMX moves - Japheth, 16.02.2009, 22:05
    • MMX moves - rr, 16.02.2009, 22:11
      • MMX moves - Japheth, 17.02.2009, 13:52
        • MMX moves - Laaca, 17.02.2009, 16:29
          • MMX moves - Japheth, 17.02.2009, 17:16
            • MMX moves - Laaca, 17.02.2009, 18:56
      • MMX moves - marcov, 18.02.2009, 09:55
  • MMX moves - FFK, 16.02.2009, 23:04
  • MMX moves - Rugxulo, 17.02.2009, 00:54
  • MMX moves - FFK, 17.02.2009, 21:37
    • MMX moves - Rugxulo, 18.02.2009, 00:48
    • MMX moves - Japheth, 18.02.2009, 09:08
      • MMX moves - FFK, 18.02.2009, 09:44