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Re: [PATCH] x86: Add .nop directive to assembler

On Mon, 26 Feb 2018 20:17:30 +0100
John Darrington <john@darrington.wattle.id.au> wrote:

> On Mon, Feb 26, 2018 at 11:03:12AM -0800, H.J. Lu wrote:
>      On Mon, Feb 26, 2018 at 11:00 AM, John Darrington
>      <john@darrington.wattle.id.au> wrote:
>      > I haven't read every post in this thread, nor do I pretend to understand all the
>      > issues.
>      >
>      > But it this change seems to have the effect that any instruction called "NOP"
>      > in the .s file are completely ignored :(
>      >
>      > Many cpus have  a NOP instruction. It's often used in realtime systems to
>      > implement short delays.
>      
>      Which target have you tried?
>      
> 
> hcs12z

+1 to John Darrington.

nop indeed used as delay (for RISC processors, like SPARC, it is well specified delay)
on programming over bare metal. Ignoring it will lead to a catastrophic effects.

--

  - ptr
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