Re: Byte ordering (was: Whether something is RISC or not)

On Thu, 03 Oct 2024 09:39:03 GMT, Anton Ertl wrote:

BTW, at least in my 32-bit PowerPC manual the claim is that PowerPC is a
64-bit architecture, and that the manual describes only the 32-bit
subset.  Maybe the original Power was 32-bit.

I would say IBM designed 32-bit POWER/PowerPC as a cut-down 64-bit
architecture, needing only a few gaps filled to make it fully 64-bit.

The PowerPC 601 was first shown publicly in 1993; I can’t remember when
the fully 64-bit 620 came out, but it can’t have been long after.

Motorola did a similar thing with the 68000 family: if you compare the
original 68000 instruction set with the 68020, you will see the latter
only needed to fill in a few gaps to become fully 32-bit.

Compare this with the pain the x86 world went through, over a much longer
time, to move to 32-bit.