At&T Assembly indexing arrays and declaring arrays

Question

How would I go about indexing and declaring arrays in AT&T assembly?

Declaring do I do it like this:

array:
    .zero 256

Creates array of 256, with values of zero.

Indexing it do I do it like this:

movq $array, %r14                //Set array to a register name
                                 //Say that r11 has the number 5 stored
movq (%r14, %r11, 8), %r15       //This will make r15 at index 5 of array
movq %rbx ,%r15                  //This will store value of rbx into r15

Is this how I do it? If not, how do I go about creating and indexing arrays in AT&T assembly?

Answer 1

Your assembly will store the address of the start of the array in r14 , move the value of the r11 th element of the array into r15 , then move the value in rbx into r15 . It will not move any value into the array. If you want to move the address of the r11 th element into r15 then move the value in rbx to the r11 th element of the array, you would need to use leaq (%r14, %r11, 8), %r15 to move the address of the r11 th element of the array into r15 , then use movq %rbx, (%r15) to move the value in rbx to the r11 th element of the array.