[raspi-internals] Re: vector questions
- From: Volker Barthelmann <vb@xxxxxxxxxxxx>
- To: raspi-internals@xxxxxxxxxxxxx
- Date: Fri, 31 May 2013 11:22:07 +0200
On 30.05.2013 16:02, Herman Hermitage wrote:
> Next, I am confused about the H/HX/HY, especially with arithmetic
> instructions.
>
> Originally, I assumed, using HY in arithmetic instructions would perform
> 32bit arithmetic. This does not seem to be the case, but rather cause a
> 16bit operation followed by a sign extend to 32bit. Is this correct?
Set bit 9 of the first half word for scalar values to not sign extend 15th bit to
16->31
Thanks, seems to work for most instructions. Not vmul, though.
Volker
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