[PATCH v4 04/12] ARM: entry: Fix iWMMXT TIF flag handling

[Nicolas Pitre]

On Mon, Mar 20, 2023 at 2:19 PM Ard Biesheuvel <ardb at kernel.org> wrote:

> The conditional MOVS instruction that appears to have been added to test
> for the TIF_USING_IWMMXT thread_info flag only sets the N and Z
> condition flags and register R7, none of which are referenced in the
> subsequent code.

Really?

As far as I know, the rsb instruction is a "reversed subtract" and that 
also sets the carry flag.

And so does a move with a shifter argument (the last dropped bit is 
moved to the carry flag).

What am I missing?


Nicolas