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    SubjectRe: [patch 13/17] Immediate Values - x86 Optimization
    Mathieu Desnoyers wrote:
    >
    > Ok. Sorry, it's been a few months since we looked at this. So the =q
    > opcode lets the compiler choose instructions with or without REX prefix.
    > We can allow this because
    >
    > - We don't need the opcode length in the stop_machine_run() version
    > - we support variable length opcode in the nmi-safe version
    >
    > Am I remembering correctly now ?
    >

    Yes. Both =r and =q allow REX opcodes.

    -hpa


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