## STD-PROPOSALS | |

**Subject:** Re: [std-proposals] Restrict possible values of CHAR_BIT

**From:** Tom Honermann (*tom_at_[hidden]*)

**Date:** 2019-10-24 12:32:47

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What is the motivation?Â What problem(s) would this solve?

Tom.

On 10/24/19 1:30 PM, Lyberta via Std-Proposals wrote:

> I propose to restrict possible values of CHAR_BIT to be 8 * (2 ^ n)

> where n is a non-negative integer.

>

> This gives values of 8, 16, 32, 64, 128 and so on.

>

> I have surveyed the most likely hardware architectures that would not

> fit with this restriction - computers with 24 bit bytes i.e. where

> CHAR_BIT == 24.

>

> The most extensive information I could find is on Wikipedia:

>

> https://en.wikipedia.org/wiki/24-bit

> https://en.wikipedia.org/wiki/Category:24-bit_computers

>

> It seems like the only candidate that is still relevant is Motorola

> 56000 series:

>

> https://en.wikipedia.org/wiki/Motorola_56000

>

> However, the specification says that it uses 8 bit bytes:

>

> http://cache.freescale.com/files/dsp/doc/inactive/DSP56000UM.pdf

>

> Therefore, I couldn't find implementations where CHAR_BIT == 24 which

> means other more exotic cases probably never existed.

>

>

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