Re: is Vax addressing sane today

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.