llvm dev - Jul 2013 - [LLVMdev] Trap instruction for ARMv7 and Thumb

HI group.

I was wondering why the "trap" instruction is implemented in the ARM
backend as an undefined opcode. For ARM mode, it uses 0xe7ffdefe, for
Thumb 0xdefe.

Why not use the BKT #imm instruction?
Does anybody remember the reason behind this?

Thanks,
Mihai
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The OS delivers different signals on each of these instructions. I had a
discussion about this with Jim Grosbach when checking in the NaCl TRAP, see
the commit archive.


On Thu, Jul 18, 2013 at 7:36 AM, Mihail Popa <mihail.popa at gmail.com>
wrote:
> HI group.
>
> I was wondering why the "trap" instruction is implemented in the
ARM
> backend as an undefined opcode. For ARM mode, it uses 0xe7ffdefe, for
> Thumb 0xdefe.
>
> Why not use the BKT #imm instruction?
> Does anybody remember the reason behind this?
>
> Thanks,
> Mihai
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
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