[PATCH 3/3] score: Add _CPU_Instruction_illegal()

[Gedare Bloom]

On Fri, Jul 20, 2018 at 11:46 AM, Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
> ----- Am 20. Jul 2018 um 16:28 schrieb Gedare Bloom gedare at rtems.org:
>
>> I want to reiterate my comment that some ISAs have valid instructions
>> with an encoding of all zeroes. Off the top of my head, MIPS32 of all
>> 0s is the encoding for sll $0, $0, 0, which is a nop.
>
> Yes, I added some special instructions on some architectures, but I don't know all of them. I will try to use the "illegal" instruction on m68k.
>
> Do you now an opcode for MIPS?
>

I think all 1s is an undefined/illegal opcode for mips, so .word -1 might work

>>
>> I am not too sure about the purpose of the test anymore, as if an
>> illegal instruction exception occurs, the alignment/data access
>> exception does not get executed.
>
> Yes, I will remove this stuff in v2.