[flac-dev] Questions about libFLAC and SSE/SSE2/...

[lvqcl.mail]

Erik de Castro Lopo wrote:

> lvqcl.mail wrote:
>> now. Removing OS check will greatly simplify src/libFLAC/cpu.c.
>
> That makes sense.

Should I post a patch that removes OS check and keeps only CPU check?


>> 2.
>> "configure" build system adds -msse2 option by default. It means that
>> x86 (32-bit) library won't work on older, non-SSE2 processors. So if

> It does that depending on the architecture. Since Debian won't be  
> supporting
> i386 for the next release, I wonder how important that is.

As far as I understand, Debian 9.0 Stretch will support i386/x86
_architecture_, it just won't support 386/486/586 _processors_.
It will work on i686+ CPUs, and some of them (Pentium Pro, II, III,
Athlon, Athlon XP) don't support SSE2.

>> FreeBSD just comments out this option:
>> <https://svnweb.freebsd.org/ports/head/audio/flac/files/patch-configure?view=markup#l28>
>>
>> Maybe it makes sense to remove this option?
>
> Without knowing why FreeBSD disabled it, I'd prefer not to change it.

Probably because they want to build libFLAC so that it supports older
processors?

>> 3.
>> What's the intended meaning of --enable-sse / --disable-sse options?
>> What should they do/enable/disable?
>
> I really could not tell you without reading configure.ac and the code.

Actually I don't want to know its current meaning, I can figure it out
myself. I want to know what it _should_ do, ideally...