I'm not familiar with the internals of how it was originally done in the
SID, but the answer to that is a solid yes.

Pseudo-random noise generators based on shift registers and logic gates
have been around for a very long time, and changing how fast you clock the
shift registers will change the upper frequency of the noise generated.

This was discussed back in July last year, and I believe there is limited
space in the C1 without trimming back other functionality and
compatibility. SID emulation has been done in the same chip as FPGA64 on
much larger FPGAs but it takes a lot of space.

On Sat, 21 Jun 2008, Payton Byrd wrote:
> Would it even be possible to replicate the white noise generator with just
logic? That's part of what makes the SID special.
>
> From: Chris [xc8/Bronx]
> Sent: Saturday, June 21, 2008 1:15 AM
> To: cone_cores@yahoogroups.com
> Subject: [cone_cores] Re: SID
>
>
> Hi,
>
> Is there any possibility to have SID emulation on the c64 core?
> Or there is lack of data space?
>
> Rgds
>
> chris