[erlang-questions] Testing reliable floating points exeption fails on x86?

Sergei Golovan <>
Wed Sep 19 13:29:28 CEST 2007


Hi!

Could someone explain me what 'reliable floating points exceptions'
are and how their reliability is checked?

I'm packaging erlang/OTP for Debian GNU/Linux using two erlang
flavours: with and without HiPE (HiPE enabled architectures are i386
(x86), amd64 (x86_64), powerpc and sparc). If I understand correctly,
HiPE refuses to build if floating points exceptions are unreliable.

I built erlang on x86 architecture many times and test for reliable fp
exceptions never failed. But recently I've got a bugreport
(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=442965) where the
test fails.

1) Could it be that the test fails due to false negative (probably
because it was run on x86_64 hardware, though I never managed to get
it failed using both 32-bit and 64-bit kernel with 32-bit userland)?

2) I'm tempted to disable this test in a Debian source package and
undefine NO_FPE_SIGNALS only for 4 architectures mentioned above. Will
this cause any harm if erlang is built without HiPE support (for those
4 arches there are two erts - with and without HiPE and users select
which to use)? Or fp exceptions play certain role even in this case?

Cheers!
-- 
Sergei Golovan



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