Question

In the next code:

section .data
    sa db ’abxdefghxl’,0
    la  EQU $ - sa
    sb db ’abcdexghil’,0
section .text

As I saw in my program, when I do mov ecx, la – then I got the number 11 in ECX.
I didn’t understand why – the number of abxdefghxl is not 10. We also count the 0?

Answer 1

Assume sa to start at 0x400. You have defined 10 ( abxdefghxl ) plus 1 ( 0 at the end ) And hence la wwould start at 0x40B. $ represents the current instruction/directive address. Hence $-sa = 0xB or 11