ASM Community

Hi all,
I'm pretty new to assembly programming so plz bare with me on this one ;). I'm trying to print a character to a given place in a console window.

;Försök till ett spel, testar bara lite.
;C++arl Dec 2008

;inkludera makro för win32 API
include 'C:\Users\Carl\Programmering\Assembly\Fasm\INCLUDE\win32ax.inc'

.data

        ;first you need to name your struct
        struct COORD
                x db ?
                y db ?
        ends

        ;then you need to reserve space for it
        coord1 COORD ;you don't need the '?' because it's already inside the struct
        rb sizeof.COORD * (2 - 1) ;unfortunately this is currently required because the 'dup' instruction can't handle structs yet
                                        ;but hopefully it will be soon.

        con_handle DD ?
        tan_handle DD ?
        char DB ?
        read DB ?
        written DB ?
        bokstav DB 'A', 00h

.code
        start:
                ;skapa console fönster
                invoke AllocConsole

                ;skaffa tangentbords handle
                invoke GetStdHandle, STD_INPUT_HANDLE
                ;flytta return värdet som hamnar i EAX till handle
                mov , eax ;handle blir en pekare till tangentb.

                ;skaffa skärm handle
                invoke GetStdHandle, STD_OUTPUT_HANDLE
                mov , eax

                ;skriv till console
                mov , 10    ;IS THIS WHERE I GO WRONG?
                mov , 8     ;IS THIS WHERE I GO WRONG?
                invoke SetConsoleCursorPosition, , coord1

                invoke WriteConsole, , bokstav, 1, written, 0

                ;läs från tangentbord
                invoke ReadConsole, , char, 1, read, 0

                ;avsluta
                invoke ExitProcess, 0

.end start

The code above results in the character 'A' being printed at the top left corner of the console screen, but i want it to be printed at column 10, row 8.

I'm on vista, if that matters.

Any help will be greatly appreciated!

/C++arl

Firts of, thx for taking time ;)

Yeah, i think youre right regarding that the SetCursorPos... wants a structure, not a pointer, so I try this:

invoke SetConsoleCursorPosition, , word 

which compiles fine but when running the program the console window just opens and closes immiditely, and it should wait for enter before closing. So just out of curiosity I tried this:

invoke SetConsoleCursorPosition, , dword 

Note that I've changed the word directive to dword. That too compiles fine but when run it prints 'A' at the top left corner (just as if coord1.x and coord1.y were both set to 0). So i guess I have two questions now :P
1. Why does the program shut down immiditely when using word, but not with dword? and,
2. How do I get SetCursorConsolePosition to work as intended?

//C++arl :)

maybe like this:

mov eax, 10
shl eax, 16
mov ax, 8
invoke SetConsoleCursorPosition, , eax

Oh btw:

struct COORD
                x db ?
                y db ?
ends

Shouldn't that be:

struct COORD
                x dw ?
                y dw ?
ends

Got it now! ;) And I understand why it works, and did'nt work, aswell now thanks to you guys, really great help.

Yes, is should be

struct COORD
                x dw ?
                y dw ?
ends

I thought SHORT was only a byte, no wonder things got fubar with me pushing whack to the stack. I especially like this way

mov eax, 10
shl eax, 16
mov ax, 8
invoke SetConsoleCursorPosition, , eax

of doing it, its clean and i know what I'm doing, plus I dont need to waste space on a variable. Thing is I'm so used with higher level languages that I dont see all the possibilities with assembler. I mean,

invoke SetConsoleCursorPosition, , (5 or (4 shl 16))

thats not the way its done in Java :P.

A few follow-up questions though.

1. How would MASM do it then? and,
2. Do you reckon I should switch to MASM, what are the pros and cons for each the 'dialects'?

thx,
~ C++arl