Re: Tutorial for beginners
From: Jim Carlock (anonymous_at_127.0.0.1)
Date: 03/03/04
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Date: Wed, 3 Mar 2004 07:41:30 +0000 (UTC)
I did one of my first assembly programs in DOS. It was DOS
4.01.
Here it is:
Start Debug.exe
-n Hello.com
-rcx
500
-a 100
mov ah, 09
mov dx, 300
int 21
int 20
-db 300
'Hello$'
You'll see some other things. The - represents the DEBUG
prompt. DEBUG is a program used to look at small .com files.
It'll work with .exe files as well, but I've not made it quite that
far yet to qaulify myself. When you're typing in some of the
things above, you'll need to hit the ENTER key at the end of
the typing. Basically assembly is moving data into registers...
the registers consist of AX, BX, CX, DX. These registers are
all 16-bit registers. They are also called EAX, EBX, ECX and
EDX. The AX register can be broken down into AH and AL.
EAX can be broken down into two things I think, but I haven't
got that far. I might be wrong on some things. I'm looking for
help and support... I think I'm typing things in the correct way.
<g> I'm just now starting to get back into it and I really need
some crash course lessons, so I figure that someone will fix
what I'm messing up! <G> I hope!
The n command in DEBUG is the NAME command. Oh...
you need to type the Q command after everything above to
get out of DEBUG.
The Interrupt 21 is the DOS display string command. I'm sure
there's some fancier name for it but what it does, is it displays
a $ terminated string that's pointed to by the DX register.
You can get some help with the other DEBUG commands by
typing ? at the dash -.
I hope that helps to get you started.
There are a thousand DOS Interrupt 21 commands. They all
do something different. The different functions are specified by
what's put into the AH register. In the case above, it's called
Function 9h. As you'll notice, DEBUG works in hex.
Cheers to you.
-- Jim Carlock http://www.microcosmotalk.com/ Post replies to the newsgroup. "Sathyaish" <VisualBasicLearner@yahoo.com> wrote in message news:7b662036.0403020054.308ef27d@posting.google.com... Thanks a tonne, Randy. I have been programming VB and Win32 API (SDK) for the last six and a half years now. While I've worked extensively on Win32, I am only familiar with C, C++ and MFC. I have no knowledge of assembly though. Thank you so much once more. Regards, Sathyaish Chakravarthy "Randall Hyde" <randyhyde@earthlink.net> wrote in message news:<CZS0c.17145$aT1.9279@newsread1.news.pas.earthlink.net>... > http://webster.cs.ucr.edu > The Art of Assembly Language Programming. > Though it does assume some familiarity with high-level languages. > Check out Jeff Duntemann's book "Assembly Step-By-Step" if > you're attempting to learn assembly language as your first language. > Cheers, > Randy Hyde > > "Sathyaish" <VisualBasicLearner@yahoo.com> wrote in message > news:7b662036.0403010236.53fd1c00@posting.google.com... > > Sorry for sounding dumb. Where can I find a web tutorial on the > > assembly language for absolute beginners? > >
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