Addressing array elements in nasm

assemblynasm

I'm very new to assembly and NASM and there is a code:

    SECTION .data       
array db 89, 10, 67, 1, 4, 27, 12, 34, 86, 3
wordvar dw      123     

    SECTION .text       
        global main     
main:               

    mov eax, [wordvar]
    mov ebx, [array+1]
    mov ebx,0       
    mov eax,1       
    int 0x80

Then I run the executable through GDB eax register is set to value 123 as intended, but in ebx there is some mess instead of the array elements value.

Best Answer

Since you're loading 32-bit values from memory, you should declare array and wordvar using dd rather than db/dw so that each entry gets four bytes:

array   dd 89, 10, 67, 1, 4, 27, 12, 34, 86, 3
wordvar dd 123

Also, the indexing in the following is wrong:

mov ebx, [array+1]

You probably meant:

mov ebx, [array+1*4]
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