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How do you clear the screen and move the cursor in a console app?

I did a search and I got a bunch of hits that were windows related.

Thanks for all your patience with me.

There are library modules in MASM32 to do this.

Try to study this C code

#include <windows.h>

void gotoxy(int x, int y){
    HANDLE hnd = NULL;
    COORD coord;

    coord.X = x;
    coord.Y = y;

    if (!hnd) hnd = GetStdHandle(STD_OUTPUT_HANDLE);

    SetConsoleCursorPosition(hnd, coord);
}

void clrscr(void){
    HANDLE hnd = NULL;
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    COORD coord = {0,0};
    DWORD dummy;

    if (!hnd){
        hnd = GetStdHandle(STD_OUTPUT_HANDLE);
        GetConsoleScreenBufferInfo(hnd, &csbi);
    }

    FillConsoleOutputCharacter(hnd,' ', csbi.dwSize.X * csbi.dwSize.Y, coord, &dummy);

    gotoxy(0,0);
}

The very rough translation of gotoxy in MASM32 will be something like this (http://masm32.com/board/index.php?topic=3078.5):

include \masm32\include\masm32rt.inc

.data?
hStdOut HANDLE ?

.code

start:
        invoke GetStdHandle,STD_OUTPUT_HANDLE
        mov  hStdOut, eax
        invoke SetConsoleCursorPosition, eax, 0A0027h       
        print chr$('X')
        invoke SetConsoleCursorPosition, hStdOut, 0C0000h 
        inkey
        exit

end start

Not sure how to translate the clrscr part though  :redface:

Put an int 3 before the Print At and launch Olly 8)

include \masm32\MasmBasic\MasmBasic.inc      ; download (http://masm32.com/board/index.php?topic=94.0)
  Init
  .While 1
      For_ ct=0 To 15
            Print At(ct+1, Locate(y)+1) CColor(cBlue, cYellow) Str$("Line %i", ct)
      Next
      Inkey CrLf$, "hit any key to continue, c for CLS, Escape to exit"
      .Break .if eax==VK_ESCAPE
      .if eax=="c"
            Cls
            PrintLine "Cleared"       ; documentation (http://www.webalice.it/jj2006/MasmBasicQuickReference.htm#Mb1120)
            Delay 500
      .endif
  .Endw
EndOfCode

Have a look at the  cls & loc macros in the masm32 library

Full translate (?) of the c code

;@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
gotoxy PROC x:DWORD,y:DWORD
local hnd:HANDLE,coord:COORD
mov hnd,0
mov eax,x
mov coord.X,ax
mov eax,y
mov coord.Y,ax

invoke GetStdHandle,STD_OUTPUT_HANDLE
mov hnd,eax
.if eax != 0
invoke SetConsoleCursorPosition,hnd, coord
.endif
ret
gotoxy ENDP

clrscr PROC
local hnd:HANDLE,NumberOfChar:DWORD
local csbi:CONSOLE_SCREEN_BUFFER_INFO
local coord:COORD
local dummy:DWORD
mov hnd,0
mov dword ptr [coord],0   
invoke GetStdHandle,STD_OUTPUT_HANDLE   
mov hnd,eax
.if eax
invoke GetConsoleScreenBufferInfo,hnd, addr csbi
mov edx,0
movzx ecx,csbi.dwSize.Y
movzx eax,csbi.dwSize.X
mul ecx
mov NumberOfChar,eax
invoke FillConsoleOutputCharacter,hnd,32,NumberOfChar , coord,addr dummy
invoke gotoxy,0,0
.endif

ret
clrscr endp

main PROC C argc:DWORD,pargv:DWORD
invoke InitInstance,1
;---- code here --------
invoke printf_s,TXT(13,10,13,10,13,10,"hello,This string must be erased if you press a key",13,10)
invoke _getch
invoke clrscr
invoke printf_s,TXT(13,10,"Press a key to quit",13,10)
invoke _getch
invoke InitInstance,0
mov eax,0
ret
main endp


It's a code who use the Windows 10 crt.If :
"Vcruntime140.dll not found"
You need the "redistributables packages  Visual C++ 2015",search MSDN for them.It's a free download

clear screen is not as simple as it should be - lol

moving the cursor is simple - SetConsoleCursorPosition

Quote from: dedndave on October 29, 2015, 12:22:04 AM
clear screen is not as simple as it should be - lol

I agree :bgrin:

But a n-100 MB download to get Vcruntime140.dll is perhaps a little overkill ::)

It can be done with a 53 bytes macro (push/pop ecx included):

include \masm32\include\masm32rt.inc ; plain Masm32 for the fans of pure assembler
include Cls.asm
.code
start:
xor ebx, ebx
.Repeat
print "line "
inc ebx
print str$(ebx), " xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", 13, 10
.Until ebx>20
inkey "hit any key"
Cls   ; <<<<<<<<<<<<<<<<<<< 53 bytes <<<<<<<<<<<<<<
print "screen cleared!"
MsgBox 0, "Cute", "Hi", MB_OK or MB_SETFOREGROUND
exit

end start

P.S.: For fans of special effects, Cls takes an optional parameter, e.g. Cls "."

this one allows you to clear individual screen buffers
it can easily be modified to clear the main buffer

        OPTION  PROLOGUE:None
        OPTION  EPILOGUE:None

ConCls  PROC    hConsole:HANDLE

;Clear Console Screen Buffer, DednDave 12-2011
;
;  This function allows the use of multiple screen buffers, clearing
;only the buffer specified by hConsole. Space characters and the current
;foreground/background attributes for the specified buffer are used.
;
;Call With: hConsole = handle of console screen buffer to clear
;
;  Returns: EAX = screen position (0,0)
;           ECX = total number of characters in screen buffer
;           EDX = buffer character attributes used to clear
;           all other registers preserved

        push    ebx
        push    edi
        mov     ebx,[esp+12]                  ;EBX = hConsole
        xor     edi,edi
        sub     esp,(sizeof CONSOLE_SCREEN_BUFFER_INFO+3) and -4
        INVOKE  GetConsoleScreenBufferInfo,ebx,esp
        movzx   eax,word ptr [esp].CONSOLE_SCREEN_BUFFER_INFO.dwSize.x
        movzx   edx,word ptr [esp].CONSOLE_SCREEN_BUFFER_INFO.dwSize.y
        mul     edx
        push    edx
        INVOKE  FillConsoleOutputCharacter,ebx,32,eax,edi,esp
        pop     eax
        movzx   edx,word ptr [esp].CONSOLE_SCREEN_BUFFER_INFO.wAttributes
        push    edx
        push    eax
        INVOKE  FillConsoleOutputAttribute,ebx,edx,eax,edi,esp
        INVOKE  SetConsoleCursorPosition,ebx,edi
        pop     ecx
        pop     edx
        xchg    eax,edi
        add     esp,(sizeof CONSOLE_SCREEN_BUFFER_INFO+3) and -4
        pop     edi
        pop     ebx
        ret     4

ConCls  ENDP

        OPTION  PROLOGUE:PrologueDef
        OPTION  EPILOGUE:EpilogueDef

geez .. you guys are awesome!

thanks again for all your patience with me