Quick question about... this question

[LordAdef]

Hey guys!
Is there any gain if I've got many bitblt invokes and I move an address to a register?
Say, this is one:

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inv  BitBlt, hBufferDC, 0, 0, CHAR_LINE_COUNT * CHAR_WIDTH, CHAR_HEIGHT, \   
               assets.terrain.hdc, trn.frmx[edi], eax, SRCCOPY
Now I use esi to hold assets.terrain.hdc:

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push esi
mov esi, assets.terrain.hdc
inv  BitBlt, hBufferDC, 0, 0, CHAR_LINE_COUNT * CHAR_WIDTH, CHAR_HEIGHT, \   
            esi, trn.frmx[edi], eax, SRCCOPY
pop esi
Just consider there is more than one call to bitblt
Cheers

[hutch--]

Alex,

With an API call, the total overhead is so high that loading a register does not give you a speed advantage. Use a memory operand as they don't change and get passed to the system DLL as memory in any case. Always try and find a way to use less registers in ordinary code so you have them when you need them.

[LordAdef]

Alex,

With an API call, the total overhead is so high that loading a register does not give you a speed advantage. Use a memory operand as they don't change and get passed to the system DLL as memory in any case. Always try and find a way to use less registers in ordinary code so you have them when you need them.

Cheers Hutch!

[jj2007]

Is there any gain if I've got many bitblt invokes and I move an address to a register?

Speedwise, as Hutch rightly notes, it will not make any difference. Sizewise, if assets.terrain.hdc is a global variable, then you need two invoke xxx, ..., esi to gain one byte less executable size.

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include \masm32\MasmBasic\MasmBasic.inc
.data?
rc RECT <>

  Init
  Cls
  repeats=1
rcglobal_s:
  REPEAT repeats
invoke GetWindowRect, rv(GetConsoleWindow), addr rc 
  ENDM
rcglobal_endp:
  deb 4, "Rect", rc.left, rc.top, rc.right, rc.bottom

rcreg_s:
  push esi
  mov esi, offset rc
  REPEAT repeats
invoke GetWindowRect, rv(GetConsoleWindow), esi
  ENDM
  pop esi
rcreg_endp:
  deb 4, "Rect", rc.left, rc.top, rc.right, rc.bottom
  CodeSize rcglobal
  CodeSize rcreg
EndOfCode

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repeats=1:
16      bytes for rcglobal
19      bytes for rcreg
repeats=2:
32      bytes for rcglobal
31      bytes for rcreg
repeats=3:
48      bytes for rcglobal
43      bytes for rcreg
... etc ...

[daydreamer]

now I got curious about related question,which is best?
when calling a PROC that has loop with GDI invokes,calling from WM_PAINT when to structure up lots drawing code,I tried use two ways of make draw PROC's
1:hdc's and other handles are global variables?
2:hdc's are WM_PAINT's local variables and with invoke draw,hdc,handle2,handle3,handle4,its transferred to draw PROC?

[daydreamer]

would be interesting to time a loop with imageblt'ing on different cpu/gpu's,because its probably gpu depending ,would be good to know

[LordAdef]

Hi Daydreamer,


Good questions!