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assemblyx86nasm

What do the brackets mean in NASM syntax for x86 asm?

Given the following code:

L1     db    "word", 0

       mov   al, [L1]
       mov   eax, L1

What do the brackets in [L1] represent?

This question is specifically about NASM. The other major flavour of Intel-syntax assembly is MASM style, where brackets work differently when there's no register involved:
See Confusing brackets in MASM32

Solution

  • [L1] means the memory contents at address L1. After running mov al, [L1] here, The al register will receive the byte at address L1 (the letter 'w').