On 23/12/22 20:54, David Brown wrote:
> On 23/12/2022 09:14, Rick C wrote:
>> On Friday, December 23, 2022 at 1:31:55 AM UTC-5, Paul Rubin wrote:
>>> I didn't personally work on it, but spent a while studying a
>>> cryptography app that ran on the now ancient Motorola DSP 56000
>>> series. The model number came from the architecture's 24 bit words
>>> and 56 bit MAC accumulator. The app wasn't particularly connected
>>> with realtime or with signal processing. Rather, the 24*24->56 MAC
>>> came in handy for high precision arithmetic used by the crypto
>>> algorithm.
>>
>> At that time there were generally, 16 bit fixed point DSP, and 32 bit
>> floating point DSP.  Neither was appropriate for audio work.  16 bits
>> is not enough resolution for high quality audio and 32 bit floating
>> point was overkill, using extra power and burning extra dollars.
>> Motorola came out with 24 bit devices as the sweet spot for high
>> quality audio work.
>
> Yes.  There are many manufacturers of 24-bit DSPs, and they almost all
> have a background in audio.
> (Now, of course, you just use the 32-bit - the millidollar difference in
> hardware costs is worth it for the added convenience.)

NXP still make DSC56xx and MC56xx (16 and 32 bit) families. No 24/56 bit
ones as far as I can see.

<https://www.nxp.com/products/processors-and-microcontrollers/additional-mpu-mcus-architectures/digital-signal-controllers/32-bit-56800ef-dsc-core:56F8XXXX-32BIT>