Re: LuaJIT performance

[Jerome Vuarand <jerome.vuarand@...>]

2009/8/14 Rob Kendrick <lua-l@nun.org.uk>:
> On Mon, 10 Aug 2009 02:36:43 +0200
> Mike Pall <mikelu-0908@mike.de> wrote:
>
>> Ok, but you may be in for a nasty surprise: the 3GS has an ARM
>> Cortex-A8 CPU which only has VFPlite. This is actually a step back
>> from the previous models which had an ARM 1176JZ(F)-S with a full
>> VFP unit. And since the vector mode of VFP is officially deprecated,
>> you're in for more surprises in the future.
>
> Have you got a citation for this?  My guy inside ARM is of the opinion
> that NEON is a /superset/ of VFP, and that there are three types for
> VFP; none, partial, and full.  Nothing on the market implements full,
> and partial is only missing a handful of instructions.

In [1] you can read:

"The VFPLite coprocessor supports all data-processing instructions and
data types in the VFPv3 architecture and is described in the ARM
Architecture Reference Manual, Advanced SIMD Extension and VFPv3
supplement."

But maybe there are non-"data-processing" instructions in VFPv3 that
are missing, or Mike refered to another VFP specification.

[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0344b/I1019986.html