1. Help on basic assembler learning
Hi there,
before entering EUPHORIA & Assembler I like to study a little
pure assembler coding.This means MASM & LINK.My problem :
I like to call function 1Ch INT 21 to get the clustersize =
and available cluster.I'm trying,since hours,to put reg CX =
and AX on the screen,the response is PC hangs.So maybe there is =
someone down the list who could give me a simple example.This
would really help me to get my self-esteem back in order.
Anyhow thanks in advance.
Karlheinz =
P.S. I downloaded all libs etc from Compuserve and Altavista,
all to complicated for beginners. =
2. Re: Help on basic assembler learning
- Posted by Jacques Deschenes <desja at GLOBETROTTER.QC.CA>
May 19, 1998
-
Last edited May 20, 1998
At 14:12 19-05-98 -0400, you wrote:
>Hi there,
>
>before entering EUPHORIA & Assembler I like to study a little
>pure assembler coding.This means MASM & LINK.My problem :
>I like to call function 1Ch INT 21 to get the clustersize
>and available cluster.I'm trying,since hours,to put reg CX
>and AX on the screen,the response is PC hangs.So maybe there is
>someone down the list who could give me a simple example.This
>would really help me to get my self-esteem back in order.
>Anyhow thanks in advance.
>
>Karlheinz
>P.S. I downloaded all libs etc from Compuserve and Altavista,
> all to complicated for beginners.
>
here is a function that return the cluster size in bytes. It assume that each
sector is 512 bytes, which I think is the case for regular PC drives.
include machine.e
function GetClusterSize(integer drive)
sequence registers
if (drive >= 'A') and (drive <= 'Z') then
drive = drive - 'A' + 1
elsif (drive >= 'a') and (drive <= 'z') then
drive = drive - 'a' + 1
elsif (drive < 0) or (drive > 26) then
return -1 -- bad drive
end if
registers = repeat(0,10)
registers[REG_AX] = #1C00
registers[REG_DX] = drive
registers = dos_interrupt(#21,registers)
return remainder(registers[REG_AX],256)*512
end function
printf(1,"current drive cluster size is %d bytes\n", GetClusterSize(0))
printf(1,"drive a: cluster size is %d bytes\n", GetClusterSize('a'))
Jacques Deschenes
Baie-Comeau, Quebec
Canada
desja at globetrotter.qc.ca
3. Re: Help on basic assembler learning
Good morning Jacques from Mannheim,
your Routine runs fine !.Thanks for that.
But I'm trying to do in real assembler,ex. with MASM & LINK.
For example :
prognam cluster
.
.
mov AH,36H ;or 1CH,1BH
int 21H
---> how to put reg AX and CX (after multiplication) on screen ??
.
.
prognam ends
end
So,one more time,thanks for your quick help.
Regards Karlheinz =
4. Re: Help on basic assembler learning
At 02:41 AM 5/20/98 -0400, you wrote:
>Good morning Jacques from Mannheim,
>
>your Routine runs fine !.Thanks for that.
>
>But I'm trying to do in real assembler,ex. with MASM & LINK.
>
>For example :
>prognam cluster
> .
> .
> mov AH,36H ;or 1CH,1BH
> int 21H
>---> how to put reg AX and CX (after multiplication) on screen ??
> .
> .
>prognam ends
> end
>
Well, you'll have a choice: you could call the dos console out routine,
or you could write direct to screen memory. Either way,
you'll first have to convert the values in the registers into readable form.
;subroutine to convert a binary number to a text string
;
; input:
; ax = number to convert
; ds:bx = pointer to end of buffer to store text in
; cx = number of digits to convert
;
; output: none
;
; registers destroyed: ax,bx,cx,dx,si
;
ConvertNumberToString PROC
mov si, 10 ; divide by
ConvertLoop:
sub dx,dx ; convert ax to doubleword in dx:ax
div si ; divide by 10
add dl,'0' ; convert remainder to a text char
mov [bx],dl ; store digit in the string
dec bx ; decrement the location of the next digit in string
loop ConvertLoop ; do the next digit
ret
ConvertNumberToString ENDP
;
; subroutine to print a string to the display using dos function
;
; input: ds:bx points to string
; output: none
;
; registers destroyed: none
;
PrintString PROC
push ax ; save these registers
push dx
mov ah, 9 ; dos function call
mov dx,bx ; point to the string to print
int 21h ; call dos interrupt
pop dx
pop ax ; restore the registers
ret
PrintString ENDP
----
Assembly programming is like hitting yourself with a large stick.
You do it because it feels so good when you stop.
Regards,
Irv Mullins
5. Re: Help on basic assembler learning
Hi Irv,
thanks for the help.With your last phrase about ASSEMBLER coding you
hit the nail right on the head.I found out that I'm using a too large
stick !.My problem is still how to get it running.Is there a possibility
that you have a short code example in your bag of tricks,ready to run ??.=
If I'm asking to much ,just .....
Anyway,thanks in advance.You could make somebody a bit calmer.
As I can see,all of you are Assembler Gurus.
Regards Karlheinz =
