Aww, and I was hoping they might have to figure out the sub al,'0' thing for themselves....

mov ah,1h ; input number
int 21h
mov dl,0ah

The result is returned in al
http://www.ctyme.com/intr/rb-2552.htm

Dunno, it's been 15+ years since I last did any 68K work.

But the essence of arrays is to load the address of an array into an 'a' register, and load the subscript into a 'd' register.

Then...

Well /2 is commonly achieved by doing >>1 (aka ASR in assembly).
Only the compiler probably knows a few more tricks than that.

Like I said, you're pitting your knowledge against the distilled...

That compilers are smarter than you perhaps?

> I literally picked up asm today.
Whereas the combined asm experience of all the people who wrote the compiler is probably in the 1000+ YEAR...

Well you didn't read this - http://www.daniweb.com/forums/announcement125-3.html

And you didn't say which assembler (nasm,tasm,masm,?asm) you're using. Do you get any error messages perchance?
...

> since asm is basically ALL about algorithms?
And every other language isn't?
Algorithms and data structures are abstract, they don't need a programming language in order to understand them,...

Knowing how the internal combustion engine works doesn't necessarily mean you're a better driver.

I've seen many experienced asm programmers turn out the most abominable C you're ever likely to...

> so why would one need to know assembly?
Curiosity mostly.

Being able to follow the code the compiler generates, and very rarely writing very small snippets works for me.

I'd guess your code.

Get better information by posting your actual code.

http://x86.org/

> PUSH 6(BP) ! here i'm putting romfile on the stack again
It's the way a compiler would do it.

> another solution would be to have a register (BX maybe?)
Also a possible way, for example...

Sure, just use the "add with carry" instruction, and you can add as many as you like.

SS means stack segment.

EBP typically moves around with ESP (BP=Base Pointer, SP=Stack Pointer).

The BP is typically used to establish a fixed point of reference for a stack frame. BP + offset...

How about
msg db 'Simple Bootloader',0

What marks the end of the string?
IIRC, some of the really low level interrupt routines used '$' to mark the end of the string.

Well you use 'divide by 10' and 'modulo 10' to extract each digit from the number, then add '0' to the result to get a printable character.

123 / 10 = 12
123 % 10 = 3
Take the 3, add '0' to it...

That sounds like a reasonable approach.

An easy implementation of a stack is simply an array which you only access at one end.

Indispensable reading.
http://www.cs.cmu.edu/afs/cs/user/ralf/pub/WWW/files.html

Int 16/AH=01h perhaps.

> I can't implement bresenham algorithm on assembly. It's too hard to do so.
So give up already and go back to doing things in a high level language if you can't deal without all the creature...

Use the link I posted.

Calculate a series of XY positions that get you from the start to the end.

For each position, call INT10H function AH = 0CH, with the other registers set to the colour...

http://en.wikipedia.org/wiki/Bresenham%27s_line_drawing_algorithm