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From: mitchalsup@aol.com (MitchAlsup1)
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Subject: Re: is Vax addressing sane today
Date: Wed, 9 Oct 2024 19:43:39 +0000
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On Wed, 9 Oct 2024 18:16:51 +0000, EricP wrote:

> Except you keep missing the point:
> no one has a handler for integer overflow because it should never
> happen. Just like no one has a handler for memory read parity errors.

Oh contrairé:
I understand how to recover from even "late write ECC violations*"--
but mostly that is because I am primarily a HW guy. (*) When a cache
line displaced from L1 or L2 arrives at L3/DRAM with a bad ECC.

> When you wrote C code using signed integers, *YOU* guarenteed to the
> compiler that your code would never overflow. Overflow checking just
> detects when you have made an error, just like array bounds checking,
> or divide by zero checking.

I disagree with this statement. I wrote in C under the knowledge
that integer data types can overflow--they have to be able to--
it is the nature of fixed size containers. I am happy for the
compiler to IGNORE the possibility of overflow, but not the HW.

> This is not something being done *to you* against your will,
> this is something that you *ask for* because it helps detect your
> errors.
> Doing it in hardware just makes it efficient.

Yes, allow the compiler to IGNORE the problem, but have HW detect the
problem.