Lesson Six: An extension help?????

Howdy all. I'm a recent convert from TASM. Wow, if only i had known.

A question on lesson six, the keyboard tut.

What i'm trying to do is have the program read a keystroke, put it on the screen, advance the "paint point" one space and then wait for another keystroke, so in essense you could type a word rather than just one letter. Here's where i screwed the proverbial pooch

.data?
xpos db ?

.....

WinMain endp
WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
LOCAL hdc:HDC
LOCAL ps:PAINTSTRUCT
LOCAL hfont:HFONT

push eax
xor eax,eax ;;ZEROING OUT EAX
mov add xpos,eax ;;TRYING TO MOV 0 to xpos
pop eax

.IF uMsg==WM_DESTROY
invoke PostQuitMessage,NULL
.ELSEIF uMsg==WM_CHAR
push wParam
pop char
invoke InvalidateRect, hWnd,NULL,TRUE
.ELSEIF uMsg==WM_PAINT
invoke BeginPaint,hWnd, ADDR ps
mov hdc,eax
invoke CreateFont,50,50,0,0,400,0,0,0,OEM_CHARSET,OUT_DEVICE_PRECIS,CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,DEFAULT_PITCH,NULL
mov hfont,eax
invoke SelectObject,hdc,hfont
invoke TextOut,hdc,300,addr xpos,ADDR char,1 ;trying to use the variable xpos to move the "cursor" one step ahead per letter typed
push eax ;Store eax on the stack
mov eax, addr xpos
add eax,1 ;add 1 to eax (xpos value)
mov addr xpos, eax ;store new value in xpos
pop eax ;restore eax from the stack
invoke EndPaint,hWnd, ADDR ps
.ELSE
invoke DefWindowProc,hWnd,uMsg,wParam,lParam
ret
.ENDIF
xor eax,eax
ret
WndProc endp
end start

My problem is that it won't assemble. Apparently eax can't be moved into xpos . I've tried mov , eax and many variants and am coming up with bupkis.

Anyone have any suggestions?

LHE

Posted on 2005-09-24 17:06:48 by LordHighExecutioner

Re: Lesson Six: An extension help?????

.data?
xpos dd ? ; TextOut requires a 32-bit variable, NOT an 8-bit one

.....

WinMain endp
WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM
	LOCAL hdc:HDC
	LOCAL ps:PAINTSTRUCT
� � � � LOCAL hfont:HFONT	

� � � �; you should zero this variable in your winmain proc. 
� � � � 
� � � � .IF uMsg==WM_DESTROY
		invoke PostQuitMessage,NULL
	.ELSEIF uMsg==WM_CHAR
		push wParam
		pop� char
		invoke InvalidateRect, hWnd,NULL,TRUE
	.ELSEIF uMsg==WM_PAINT
		invoke BeginPaint,hWnd, ADDR ps
		mov� � hdc,eax
		invoke CreateFont,50,50,0,0,400,0,0,0,OEM_CHARSET,OUT_DEVICE_PRECIS,CLIP_DEFAULT_PRECIS,DEFAULT_QUALITY,DEFAULT_PITCH,NULL
� � � � � � � � mov hfont,eax
� � � � � � � � invoke SelectObject,hdc,hfont
� � � � � � � � invoke TextOut,hdc,300, xpos,ADDR char,1

� � � � � � � � inc� xpos� �; this increases the argument (in this case: the 'xpos' variable)

	invoke EndPaint,hWnd, ADDR ps
	.ELSE
		invoke DefWindowProc,hWnd,uMsg,wParam,lParam
		ret
	.ENDIF
	xor� � eax,eax
	ret
WndProc endp
end start

I would also like to note that this program is very 'unclean'. You should always free all resources you create/allocate.

Posted on 2005-09-24 18:39:33 by ti_mo_n

Re: Lesson Six: An extension help?????

Thanks man. I need a little work. But its definiatly moving the characters ahead (erasing the one behind, but i'll figure that out. I think its the invalidate rec call.)

By unallocate, are you referring to the CreateFont, resource? Should i release it before i exit?

Posted on 2005-09-24 19:26:22 by LordHighExecutioner

Re: Lesson Six: An extension help?????

Yup. Call DeleteObject to free your font handle.

Posted on 2005-09-24 23:40:41 by roticv

ASM Community