Re: is Vax addressing sane today

On Mon, 9 Sep 2024 19:38:52 +0000, Brett wrote:

MitchAlsup1 <mitchalsup@aol.com> wrote:

On Sun, 8 Sep 2024 21:09:39 +0000, Lawrence D'Oliveiro wrote:
>

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.

>
I have not heard an argument that the complex things in VAX ISA are
a) desirable
b) performance helpful

>
Speaking of complex things, have you looked at Swift output, as it
checks
all operations for overflow?
>
You could add an exception type for that, saving huge numbers of
correctly predicted branch instructions.

Unlike RISC-V and may others; My 66000 has maskable integer exceptions.
An exception can be routed directly to a signal handler of the current
application (without a trip through GuestOS). GuestOS just has to
configure where exceptions are delivered.

The future of programming languages is type safe with checks, you need
to get on that bandwagon early.

This would/will happen faster when type-safe with checks are well
represented in benchmarks used to measure various architectural
things, and the exceptions and checks are actually utilized showing
performance degradation of lesser endowed architectures.