Re: [Xen-devel] [PATCH 3/3] x86: a little bit of 16-bit video mode setting code cleanup

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.08.2019 16:38, Andrew Cooper wrote:
> On 29/08/2019 15:23, Jan Beulich wrote:
>> On 29.08.2019 16:08, Andrew Cooper wrote:
>>> On 14/06/2019 12:38, Jan Beulich wrote:
>>>> @@ -38,9 +38,9 @@ ENTRY(wakeup_start)
>>>>          movw    %ax, %ss        # Need this? How to ret if clobbered?
>>>>  
>>>>  1:      # for acpi_sleep=s3_mode
>>>> -        testl   $2, wakesym(video_flags)
>>>> +        testb   $2, wakesym(video_flags)
>>>>          jz      1f
>>>> -        movl    wakesym(video_mode), %eax
>>>> +        movw    wakesym(video_mode), %ax
>>> Similarly, video_mode can become .word, I think.
>> But a word is less efficient to access (because of the operand size
>> override), so I'd prefer to not shrink this one. Just let me know
>> whether you agree, and I'll cook up a patch accordingly.
> 
> This is 16 bit code so it is movl which has the operand size prefix, not
> movw.
> 
> It is extern'd in C, but not wrapped in bootsym(), and I can't see it
> being read anywhere.

Oh, indeed. I'll ditch the extern then.

Jan

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