How do I clear a buffer?

[mofule]

Sup.

Once again, I have a problem. I know this is stupid but how do I clear a buffer? I've made my second stage into a shell. It stores every character into ES:DI (pointer to buffer) and compares it.

I want to clear it. How would I do that? So there's nothing in the buffer. This is how I made it.

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buffer times 64 db 0

[TheZeus121]

Hi,
At the start the buffer is already empty with zeroes, but if you want to clear it again, I would do it like this:
(supposing that es:di already points to the buffer)

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mov cx, 64      ; the length of buffer
mov al, 0       ; put zeroes everywhere
clear_loop:
stosb           ; this will put byte stored in al to the address [es:di] and increase di
loop clear_loop ; if cx is not zero, loop back and decrease cx

if you are in 32 bit mode replace cx with ecx, if in 64, then with rcx.

Note: this isn't the most effective, you could use stosw or even stosd or stosq, but this is the easiest to explain and understand IMO.

hope this helps

[Octocontrabass]

LOOP? Why not REP?

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mov cx, 64
mov al, 0
rep stosb

[CorruptedByCPU]

LOOP? Why not REP?

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mov cx, 64
mov al, 0
rep stosb

Ha ha, and where is DI/EDI/RDI?

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; nasm
xor al, al
mov cx, 0x40
mov di, buffer
rep stosb

[Octocontrabass]

Ha ha, and where is DI/EDI/RDI?

(supposing that es:di already points to the buffer)