anyone who can teach me some basics of low level programming?

[ben77]

---

mga pips... gusto lang ko magkat-on sa low level programming like Assembly or the Turbo C kay wala bitaw mi natudloi ana sa amo school.... concepts and its structure lang...


kahibaw ko na moingon na pod ni ang uban nga iresearch sa INTERNET.... gusto lang ko makakat-on sa inyong nakat-onan o nahibaw-an about some low level programming....


=)


if its ok ra pod...

[MarkCuering]

Hi ben77, Turbo C isn't a low level programming. But I suggest you to study basic C programming and then further investigate your .exe file into Win32dasm or IDAPro (this comes a free package). This is very helpful if you will be in a serious development. I suggest you not to write first any Assembly language codes, just carefully examine your small program with few input and output commands, and study various instructions such as Assembly Language Tutorials - Page4 - Assembler Language instructions - Free Computer Science Tutorials - Provided by Laynetworks.com

Don't worry or focus too much in Segment Registers (CS, DS, SS, ES) using the tools above you can directly click your mouse button and this will lead you to output the stack. As long as you have the basic concept regarding Interrupts and General purpose registers, no need to go further, just know what does the computer do when it tried to call PUSH or MOV command etc...

My knowledge is just up to plain investigation looking up those loaded functions, or jumping up few sub routines during debugging. This concept is already applied in VS2005 where you have a chance to do some live debugging while your program is running, But only if the code is available at hand and not yet compiled.

Try to make a password entry like program. Where it directly exits if the inputted string is wrong. By Investigating, you will see some operator like "JNE" Jump if not equal (call exit function) "JE" Jump if equal (continue running the program), here you have two options to change the flow of the program, its either change the Instruction or directly point out to your Function Address. Take note that memory address are written in reverse on its half, and you need to change its pointers, it is very harmful if pointing out to an empty location coz it will make some random locations. Anyway, you don't have to worry about this, coz usually it prompt you some warnings before it proceeds.

Other related tools are HIEW32, and Olly. Just try it first by investigation , before writing your own.

GoodLuck!

[nullpointer]

@MarkCuering unsa imo field of expertise sir? Asa ka gawork?

[MarkCuering]

I don't know ano field ko hehehe... I'm into offshore and rig designs/construction. but my career started way back when I won AutoCAD Engineering Design competition, National & International (Asia) early in my college years competing other countries like malaysia, korea... Until one day, I found myself working at good exposure in hardware such as MCU devices until I ended up when Keppel and Autodesk offered me some nice thing to be done and introduce me a new software (a solution that provides everything in a serious engineering designs). A year after I graduate in Comp. Eng'g. I got a job offer here in SG & Indonesia... same software but my job is to implement it over 7,000 workers...and later on provide some client & customer side applications.

More in 3D modelling, computing, and mathematical analysis (stress, thermal, loading etc...) Happy to work as design supervisor and system administrator, But Planning to go back my hometown Cebu and maybe settle down for abit, since my girlfriend would die askng me "is it done?", "how was your code now?" "when can be finish?" LOL... I'd like to Introduce this kind of software to most of universities and the needs of both programming & engineering background, but I love to see first people who are in Python & OpenGL who are keen to solve Math problems. cheers.... struggling to find professionals or student who are in python. LOL... I found an old thread but only two people are active, unfortunately they're into Web design field. hehehe

[simoncpu]

That is cool!

[tristen]

bro ako sd nahan ko mkhibaw about programing..pero d na gd ni ako field..study lng bro

bacn naay mka.ad og knwledge nmu dri..

[mustrufnuthn]

@MarkCuering
are you familiar with "Terminate and Stay Resident " programming using assembly?
need to know the structure...

thanks

[cold_fusion]

are you familiar with "Terminate and Stay Resident " programming using assembly?
need to know the structure...

TSR's are for old DOS systems. With windows, this is not needed anymore.

To make a DOS program a TSR, you need to terminate it with int 27h I think.
It's been 15 years since I played with DOS.

The TSR program function (callback) is done by changing the interrupt vectors and point to your own.
After ones custom function is done, calling again the original interrupt is an option.

Disk interrupt, keyboard interrupt and 18.2/sec timer are the ones commonly modified (hooked).
Changing int 21h (DOS functions) is a problem because it's not re-entrant.

BTW, why do you need to program a TSR app? Old DOS virus?

[MarkCuering]

Sorry bro, I'm not that good in assembly. Where you gonna use TSR? are you into Hardware din ba? or you just want to study Assembly language? I used to program TSR way back Turbo Pascal 5.5-6.0. in an old 386 machines under MS Dos 6.0. and Yes, you need to know few Interrupt vectors to call on. This would actually let your DOS(single-task-os) do some few muti-tasking, which is now obselete in Windows. TSR programs are useful in some dos applications such running a "CLOCK" on top of your screen (similar to system clock in windows). I don't know if you can have more than 1 TSR at the same time, since this is limited I guess (talking about DOS, which we use to have 640KB (compiler theory), though TSR runs in extended memory, still your extended rmemory depends upon your compiler & your operating system. But in case you're writing it in C or Pascal and meet some errors "STACKS EXCEEDED" or similar (I really forgot) try to break it up. The rest of the loaded functions will be place into extended memory. Which sometimes gives some conflict in your TSR programs right after you close your application, which your TSR program places in Extended memory and continually running. Whatever trigger you've been set like "Ctrl-Key" or "Function-Keys" it will not take any effect... if it happens to you, try checking your extended memory from any debugger (found in pascal).

If you are a computer engineering student... you will gain more knowledge on this in your Logic Circuit II where you can test your multiplexer and decoder in a mini MCU device trainer, where it is possible to use XMS of up to 1MB. This is more helpful rather than creating some old DOS Viruses. The old Norton Disk Doctor and PC Health also runs in TSR... that monitors any disk activity and of course block any TSR viruses not that it guards/scans but it occupies almost all of its extended memory considering that you can only have of up to 1MB.

Advise you to research and download some TSR pascal programs (just for quick reading and understanding). Pascal have some tools to monitor unbuffered memory, UMB (Upper Memory Block) between 640k and 1MB useful for loading TSRs or device drivers (dos). By the way you can run any assembly code also in Pascal too... GoodLUCK!

[nullpointer]

Mga bro, is it a wise decision to study Assembly Language now having these new programming language like Java, .NET, Python, etc...? Unsa inyo ika-estorya?