How to compile Assembly code in linux fedora11 ?

fruttenboel · 06-23-2010, 03:04 PM

Quote:

Originally Posted by cvr

Sir,
By seeing just the assembly code,How can we tell the code is 16-bit or 32 bit?
In my opinion it depends on the number of data lines of the processor!
am i rite?
What is the entry function i need to give if i want to compile the assembly code? (LIKE we will give main() in c-language)

That's called 'experience'.

This

Code:

MOV AX,CX

is a 16 bit move. AH = 8 bits. AX = 16 bits. EAX = 32 bits.

This

Code:

_SND_SPKR_TONE:
MOV AL,0B6H
OUT 43h,AL ; 43h = PIT mode control word (page 377)

is a typical DOS style routine to operate the hardware timer.

I programmed in assembly on the PC between 1987 and 1999. After that I switched to a language: Modula-2.

fruttenboel · 06-23-2010, 03:06 PM

Quote:

Originally Posted by cvr

I was using cs 5536 chipset(AMD) in the above assembly code ...

It's just plain 8086 assembly code.

Don't pay attention to it. It's old fashioned code that you can not use on anything else than DOS.

Or, are we fixing your homework again?

johnsfine · 06-23-2010, 04:22 PM

Quote:

Originally Posted by cvr

By seeing just the assembly code,How can we tell the code is 16-bit or 32 bit?

Let me expand on that "experience" answer you already got.

If you can read asm code, you can see that chunk of code has two 16 bit operations and several 8 bit operations and no larger operations.

But you can do 8 and 16 bit operations even in 32 or 64 bit mode. So nothing there absolutely rules out 32 or 64 bit mode. The listed 16 bit operations would be particularly stupid in 32 bit or 64 bit mode, but wouldn't be absolutely impossible.

All 32 and 64 bit modes are "protected" modes where any sane OS normally prevents user code from doing those I/O operations.

So combining all of the hints, an expert would have no doubt that this code was written for 16 bit mode, even if no single detail absolutely rules out 32 bit mode.

Recursion · 06-23-2010, 11:12 PM

Just to clear up some confusion. One does not compile assembly, one assembles it via an assembler.