[
Date Prev][
Date Next][
Thread Prev][
Thread Next][
Date Index][
Thread Index]
Re: Exception handling
On 2007-06-07 15:03:12 +0000, Michel Hack wrote:
For example, at the physical point of interruption, typically several
instructions beyond the logical point (in systems without a precise
interrupt mode or capability), a stack frame may have been partially
unwound. It is even possible that two frames were unwound, or that
a new frame was already (perhaps partially) activated.
IMHO, that's not a problem. All the exception handler needs to
do is to set a flag. Such a flag would just be checked at some
control points.
Preventing this type of uncertainty requires inserting synchronising
instructions (interrupt reflection barriers) at block-entry-and-exit
points, which costs plenty even when no interruptions occur,
No, they don't necessarily cost plenty. If the programmer or language
has put too many control points, this is a problem with the programmer
or the language, not with IEEE 754.
Also note that this isn't specific to FP exceptions.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / Arenaire project (LIP, ENS-Lyon)