Re: [Discuss-gnuradio] Raspberry Pi Activity?

[Thomas Tsou]

On Thu, Jan 17, 2013 at 11:20 AM, Ed Criscuolo
<address@hidden> wrote:
> I thought it has an Arm11!  From Wikipedia:
>
> "The Raspberry Pi has a Broadcom BCM2835 system on a chip (SoC),[3] which
> includes an ARM1176JZF-S 700 MHz processor.... VideoCore IV GPU,[12] and
> originally shipped with 256 megabytes of RAM, later upgraded to 512MB."

The architecture is ARM11 - the instruction set is ARMv6.

> "ARM11 is an ARM architecture 32-bit RISC microprocessor family which
> introduced the ARMv6 architectural additions. These include SIMD media
> instructions, multiprocessor support and a new cache architecture."
>
> These would seem to imply that the R-Pi has SIMD instructions available.

There are indeed SIMD instructions available for integer operations,
and the Pi may be fairly capable in fixed point operation. For
floating point, the VFPv2 coprocessor has a vector mode that speeds up
certain operations, but still runs serially. From a DSP architecture
standpoint, the floating point unit is dated and not particularly
interesting.

> In addition, the VideoCore IV GPU looks like it's a pretty capable
> DSP in it's own, capable of running it's own applications without the
> CPU.  Sounds like Volk could take advantage of it as well.

Access issues aside, that is the way the Raspberry Pi should be used.
The big, powerful GPU is the exciting part and there just happens to
be a usable ARM processor attached on the side.

  Thomas