split function in x86 asm (loop over characters of a string)

Question

So, I need split a string character by character

in JavaScript it will be like this

let text = "abcde";
for (var i = 0; i < text.lenght; i++);
{
    console.log(text.charAt(i));
}

but how to do this is in NASM?

I am not an expert in assembly, but I have already tried to solve this problem for a week

I made a function for quick output and on the calculation of the length of the message I tried to output a character pastebin.com/nEBzNqnu — Сашенька Глинин
– Сашенька Глинин, Commented Jun 24, 2022 at 17:46
What convention do you use for representing strings? If you don't know the answer to this question, just show us your code you use for defining a string and working with it. — fuz
– fuz, Commented Jun 24, 2022 at 20:10
@СашенькаГлинин you should add that into the answer! (As code, not as a link) — Marco Bonelli
– Marco Bonelli, Commented Jun 24, 2022 at 20:25

Sep Roland · Accepted Answer · 2022-06-24 18:05:34Z

4

I would not precisely call it 'splitting' a string, but rather iterating over a string.

In the data section

Define your string and make it zero-terminated:

MyText db 'abcde', 0

In the code section

Establish a pointer to the beginning of the string:

    mov  esi, MyText

Read a byte from memory:

Again:
    mov  al, [esi]

Test to see if it is the terminating zero:

    test al, al

Stop the loop if it is indeed the end-of-string marker:

    jz   Done

Output the byte in AL any way you like:

...

Increment the pointer:

    inc  esi

Go repeat reading a byte:

    jmp  Again
Done:

answered Jun 24, 2022 at 18:05

Sep Roland

41.2k10 gold badges49 silver badges90 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Seva Alekseyev Over a year ago

Nitpick: the Javascript original that the OP cites enumerates over UTF-16 halfwords (or UCS-2 characters), not over bytes. That said, the OP seems like they are at the level where they don't care.

Сашенька Глинин Over a year ago

I get a Segmentation fault on the output, most likely it's the output that I'm doing, sorry for my stupidity, but could you send me the full code?

Sep Roland Over a year ago

At the ellipsis, you could write: mov edx, 1 mov ecx, esi mov ebx, 1 mov eax, 4 int 0x80 to output the current character from the string on the screen.

Collectives™ on Stack Overflow

split function in x86 asm (loop over characters of a string)

1 Answer 1

In the data section

In the code section

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

In the data section

In the code section

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related