[GAS][ARM]Generate unpredictable warning for pc used in data processing instructions with register-shifted register operand

Nick Clifton nickc@redhat.com
Tue Oct 11 13:06:00 GMT 2016


Hi Renlin,

> In ARMARM (ARMv7-A and ARMv7-R edition),

Ah - good we are using the same manual.
 
> if d == 15 || n == 15 || m == 15 || s == 15 then UNPREDICTABLE;

Right - thanks - I was looking at the wrong instruction - CMN (register)
rather than CMN (register-shifted register). Doh!

It seems a little strange that the PC cannot be read by these type
of instructions, but if that is what the ARMARM says, then so be it.

Cheers
  Nick



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