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

[Sebastian Huber]

----- 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 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.