Programming and the OS environment

[davexnet]

I was following a thread on Mozilla Firefox and the bug had to do with executing AVX (Advanced
vector extensions) instructions and the code crashing with exception_illegal_instruction.
For these instructions to work, the CPU be must at or newer than Sandy Hook or
Bulldozer (AMD). Also, for AVX, the Windows version must be at least Windows 7 SP1.,
otherwise similar fail.

Now there are routines in the Mozilla code to test for the operating environment, but it is
sometimes fails, does not detect the situation properly, and crashes.

There is a scenario I've personally experienced but I've yet to prove it, that may affect the
above programming. A processor that supports the instructions and Windows XP. My
theory is that those with a dual boot system, for example Windows 10, first loads the Win 10
boot loader, then passes control to NTLDR to complete the XP logon. This is Vs. a native XP installation, where the XP bootsector / NTLDR gets control directly.

Could there be something lurking in the environment, perhaps the contents of a register that is
affecting the code that determines if it safe to run AVX instructions?

 

[John Connor]

CPU be must at or newer than Sandy Hook

I can tell you watch a lot of cable news like I do.

 

[davexnet]

oops... I mean Sandy Bridge !

What about my scenario, though ? What other possibilities remain that explain what I see?

I experience crashes in various software, such as Firefox and the avast anti-virus, but only when I use
XP that's been booted through the Windows 10 boot loader.

So I've been using XP's recovery console ("fixboot" command) to restore its own loader, and once this is done,
the errant behavior stops and I experience no more issues.

Any thoughts? Anybody with debugging experience willing to take a look at some diagnostic materials ?
https://crash-stats.mozilla.com/report/index/28ff9c2c-63e6-4346-b4cf-48f382161105

 

[John Connor]

I really don't know, but in my humble opinion, Win 10 is a pile of crap. I think it's very flacky from all the post's I've seen across many forums. If you need to use XP I would load it into VMware's VM Player now called something else which I can't remember.

 

[davexnet]

I like the speed and responsiveness of running it directly, don't want to use VM.
I have a similar feeling about Windows 10 and may drop it completely. Since I had a motherboard change
it is no longer activated I'll eventually have to buy something.

For now I've simply abandoned Windows 10. For all intents and purposes, it's out of the picture
since it's boot loader has been over written with the native XP loader. I use XP much more often so
that's fine for now.

Regarding the problem, I'm hoping somebody with debugging experience might be able to assist.
What does exception_illegal_instruction actually mean? In my mind, it was a real instruction not supported
by the environment, or some garbage was picked up due to memory corruption (or similar).

 

[John Connor]

or some garbage was picked up due to memory corruption (or similar).

You could always check your RAM with Memtest 86 to be sure nothing is going on there.