Odd "endianness" [was Re: RE: Base 64 posts to the list]

Paul Koning paulkoning at comcast.net
Fri Dec 9 09:02:00 CST 2016

> On Dec 9, 2016, at 1:25 AM, Chuck Guzis <cclist at sydex.com> wrote:
> On 12/08/2016 08:46 PM, Cameron Kaiser wrote:
>>>> I have an old computer that was intended to do FFTs. It has a 
>>>> complete bit order swap, MSB to LSB, instruction.
>>> Well, there's the PowerPC "endian" mode (settable in the MSR)--but
>>> it's just "sort of"--the little-endian mode simply XORs the lower 3
>>> bits of the address with 111 (i.e. "flips them").
>> Or you could use the PowerPC byte-swapped instructions (lwbrx, etc.)
> Forgot to mention the ARM CPUs/MCUs.  Supports both, for people who
> can't make up their mind.

Rather than "can't make up their mind", a good reason to have selectable endian processors is that the best choice may depend on the application.  So for embedded systems in particular, it's good to be able to pick which you want.


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