Re: use of setjmp/longjmp in x86 emulator.

From: H. Peter Anvin
Date: Mon Mar 01 2010 - 17:57:25 EST

On 03/01/2010 02:31 PM, H. Peter Anvin wrote:
> On 03/01/2010 11:18 AM, Zachary Amsden wrote:
>> It's going to be ugly to emulate segmentation, NX and write protect
>> support without hardware to do this checking for you, but it's just what
>> you have to do in this slow path - tedious, fully specified emulation.
>> Just because it's tedious doesn't mean we need to use setjmp / longjmp.
>> Throw / catch might be effective, but it's still pretty bizarre to do
>> tricks like that in C.
> Well, setjmp/longjmp really is not much more than exception handling in C.

For what it's worth, I think that setjmp/longjmp is not anywhere near as
dangerous as people want to make it out to be. gcc will warn for
dangerous uses (and a lot of non-dangerous uses), but generally the
difficult problems can be dealt with by moving the setjmp-protected code
into a separate function.

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