What is the use of .byte assembler directive in gnu assembly?

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There are a few possibilities… here are a couple I can think of off the top of my head:

  1. You could access it relative to a label that comes after the .byte directive. Example:

      .byte 0x0a
label:
  mov (label - 1), %eax

  2. Based on the final linked layout of the program, maybe the .byte directives will get executed as code. Normally you’d have a label in this case too, though…

  3. Some assemblers don’t support generating x86 instruction prefixes for operand size, etc. In code written for those assemblers, you’ll often see something like:

      .byte 0x66
  mov $12, %eax

    To make the assembler emit the code you want to have.

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