Firefox without SSE2

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eccerr0r · Post by **eccerr0r** » Thu Feb 11, 2021 6:10 am

Have anyone tried building firefox without SSE2 instructions?

My current build I have CFLAGS without specifying architecture (I thought this means default/i686) and it's illegal instructioning just firefox...

Wondering if someone has already looked into it or not. So far I'm not having much luck building such. In theory it's possible unless there was some hand assembled SSE2 code in the build which I'd have the foggiest idea how to search for it...

The_Pope · Post by **The_Pope** » Thu Feb 11, 2021 12:38 pm

Yes, someone has. But for Windows.

https://github.com/roytam1/mozilla45esr

https://github.com/roytam1/palemoon27

And I think there was another tree, too. EDIT: I think it was this one: https://github.com/roytam1/UXP

eccerr0r · Post by **eccerr0r** » Thu Feb 11, 2021 3:15 pm

Err... what about for Gentoo?
This doesn't make sense that even with the architecture set for i686 it inserts SSE2 instructions, where is it inserting them...
If only it was a pure C/C++ project..

mike155 · Post by **mike155** » Thu Feb 11, 2021 3:36 pm

See: https://stackoverflow.com/questions/507 ... lar-c-code

SSE2 is baseline / non-optional for x86-64, so compilers can always use SSE1/SSE2 instructions when targeting x86-64.

EDIT: I just realized that you are talking about x86. Sorry! But still: why do you want to avoid SSE2? It's been around since Pentium 4, released in 2000 - so every modern processor should support it, no?

Ant P. · Post by **Ant P.** » Thu Feb 11, 2021 4:31 pm

mike155 wrote:EDIT: I just realized that you are talking about x86. Sorry! But still: why do you want to avoid SSE2? It's been around since Pentium 4, released in 2000 - so every modern processor should support it, no?

There are several that don't. i686 is not synonymous with SSE, though the term has become abused as such recently.

eccerr0r · Post by **eccerr0r** » Thu Feb 11, 2021 4:33 pm

Oh yeah, I should have mentioned clearly that target=x86 32-bit.

And machines without SSE2 don't magically turn into something with SSE2, or even a P4 even :-(

Reference links
viewtopic-t-1087434-start-0.html

32 bit Processors without SSE2:
80386 all
80486 all
Pentium
Pentium Pro
Pentium II
Pentium III
Athlon using socket 462 and Slot A including Athlon XP, Athlon MP, Duron

32 bit Processors with SSE2:
Pentium M
Pentium 4 (32-bit)
Atom (e.g., N270)
Athlon using socket 754 and higher

Just bothers me if we can compile code and it still is forced to emit SSE2 instructions. Don't mind if I have to use another machine to cross compile...