CODEWITHSUNDEEP
assemblyx86bios
sample_nickname
sample_nickname

Reputation: 301

Assembly help for INT 13h on Disk Information

I am using DOSBox and nasm, trying to use int 13 in order to get hard disk information such as serial code etc. Int 13 needs:

    AH=25h
    DL=(80h,81h) and 
    ES:BX-> 512 byte buffer for reply packet.

i dont understand the requirements of the final line at all. any help?

An example would be much appreciated.

Upvotes: 0

Views: 1046

Answers (2)

0x90
0x90

Reputation: 40982

As you know es and bx are 16 bits registers.

es is the segment, while bx is the offset.

If you concatenate them [es:bx] you get the full 32 bit address (AKA pointer) to the "buffer", which the data will be copied to from the disk device.

Here is a snippet should work for you:

xor ax,ax
mov ah,25h
mov dl,80; 81h is for write probably
mov bx,0h
mov es,0800h
int 13

Upvotes: 0

Alexey Frunze
Alexey Frunze

Reputation: 62058

The registers es and bx supply the far address of the buffer to receive the data, the buffer is 512 bytes long.

Upvotes: 2

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