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From: Lawrence D'Oliveiro <ldo@nz.invalid>
Newsgroups: comp.arch
Subject: Re: is Vax addressing sane today
Date: Sun, 8 Sep 2024 21:09:39 -0000 (UTC)
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On Sun, 8 Sep 2024 17:56:55 +0000, MitchAlsup1 wrote:

> The problem with VAX was NOT that one could not put a lot of work in a
> single instruction;
> 
> no,
> 
> The problem with VAX is that it made putting too much work in a single
> instruction easy.

Perhaps there is also the issue of the wildly-variable instruction length. 
A single VAX operand descriptor could be up to 6 bytes; I think the 
instruction with the most general-format operands could have 6 of them: 
so, plus opcode, such an instruction could be 37 bytes long.

While the shortest instruction could be just 1 byte.

Even those who are talking about “post-RISC” are, I think, still in favour 
of RISC-style fixed instruction lengths.