Re: is Vax addressing sane today

On Tue, 1 Oct 2024 16:26:25 +0000, Anton Ertl wrote:

Michael S <already5chosen@yahoo.com> writes:

On Tue, 1 Oct 2024 10:12 +0100 (BST)
jgd@cix.co.uk (John Dallman) wrote:

PowerPC did for a while, but the company interested in NT on PowerPC
was IBM, and their hardware prices were a /lot/ higher than x86
prices. They didn't see that as a problem, but all the potential
customers did.

>
The ideas of ARC (MIPS) and PowerPC (which was not just IBM) was that
they would succeed the IA-32-based PC.  Given the assumed (and, around
1990, actual) performance superiority of RISCs over IA-32, this looked
plausible.  However, even with Alpha, which was often superior in
performance throughout the 1990s, and for which there were cheap
offerings (but without performance edge; e.g., I once was playing with
the idea of buying a 21164PC-based PC164SX system, where the CPU+board
(with 1MB L2 cache) cost ATS 6000 (~EUR 440) in 1998; but I went with
a K6-2, because I played some DOS games:-).  The cheap 164SX offer may
have
been a clearance sale, however.
>
In any case, the performance advantage of the RISCs vanished during
the 1990s, the RISCs never had wide ISV support, and so WNT on RISCs
flopped.

Pentium Pro wrote the death nell for 1st gen RISC architectures.
Only ARM found a new and expanding market.

Now I wonder what endiannes was used by PowerPC variant WinNT.
In theory, PPC/POWER could run in Little Endian mode, but before v3 of
POWER ISA it wasn't as full-featured as Big Endian mode. If I am not
mistaken, the difference was that in LE mode there was no support for
unaligned memory accesses.

>
Given that MIPS and Alpha require natural alignment, little-endian
PowerPC at the time was as full-featured as the other RISCs.
>
Alignment issues may have been a problem with the RISC ports, though.

One of the reasons to do misaligned in HW.

>
- anton