Bug in tutorial code

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casey

Joined: 18 Aug 2005
Posts: 35

casey 21 Sep 2005, 06:45

When I copied Sulaiman Chang's version of Iczelion's
the Mouse Input tutorial 7 it failed to work.

I tracked the problem down, as shown below, in case
Sulaiman wants to correct it.

...

wmLBUTTONDOWN:
;low order lParam = x
;high order lParam = y
mov eax,[lParam]
add eax,0xFFFF
^^^

should be,

and eax,0xFFF
^^^

Regards,

John Casey

email: jgkjcasey at yahoo.com.au

21 Sep 2005, 06:45

vbVeryBeginner

Joined: 15 Aug 2004
Posts: 884
Location: \\world\asia\malaysia

vbVeryBeginner 21 Sep 2005, 09:55

hi casey,
sorry for the bug.
i just correct it. thank you

21 Sep 2005, 09:55

snifit

Joined: 10 Dec 2004
Posts: 12
Location: Sweden

snifit 07 Oct 2005, 15:26

If you have lParam (32 bits) and want the lower 16 and the higher 16 bits, then you can also do it this way:

Code:

virtual at lParam
  lParamlow dw ? ; The lower 16 bits
  lParamhiw dw ? ; The higher 16 bits
end virtual

No idea which method that is fastest though, but doing it this way does however save you some code.

07 Oct 2005, 15:26

decard

Joined: 11 Sep 2003
Posts: 1092
Location: Poland

decard 07 Oct 2005, 15:38

In such code of window procedures speed actually dones't matter. You can also write:

Code:

movzx eax,word[lparam]    ; get low word
movzx eax,word[lparam+2] ; get hi word

07 Oct 2005, 15:38

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