assembler optimized integer overflow detection

Fredrik Lundh fredrik at pythonware.com
Mon Aug 23 14:54:23 CEST 1999


Felix von Delius <Delius at ebox.de> wrote:
> I asked myself if it will be a big performance boost when someone will
> re-code this routines in assembler, because an overflow can be detected very
> simply by checking a processor-flag after performing the operation. Has
> someone done this already? What speedup-factor would an optimization of this
> kind have to the average Python code?

well, you could always try this:

1. run a suitable set of benchmarks (make
sure you don't use benchmarks that rely
on OverflowErrors being thrown).

2. remove the overflow checks from
Objects/intobject.c and Python/ceval.c
(search for OverflowError to find them
all), and rebuild.

3. run the same set of benchmarks again.

4. post the results.

</F>





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