Why not?

Intel/AMD x86 -nobody has complied the executables for sse2/3 running Android. I'm not sure if anyone has produced an x86 version to run under Android.
ARM - sse2/3 are not relevant to the ARM architecture.

---

Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

I'm not sure if anyone has produced an x86 version to run under Android.

There's two showing in the Applications list, 8.00 (nopie) and 8.00 (pie) Android (Intel/AMD x86 processor).

The pie/nopie have nothing to do with the Android 9 version, which is called Pie, but rather with the way that applications address memory. When an application is compiled with the -pie attribute it means this application can use any arbitrary memory position, which was introduced in Android 5.0, whereas -nopie uses a fixed memory position for its applications and shared libraries, as the previous Android versions did.

As for using SSE2/3 on an x86 CPU under Android, I wonder if anyone would want that as it will increase temperatures enormously.
I've seen my phone give a warning already that the system was overheating by just running BOINC and a navigation app together, I think that would happen quite a lot more when using special SIMD registers.

---

ARM - sse2/3 are not relevant to the ARM architecture.

Oh. I didn't think of that. My fault.

As for using SSE2/3 on an x86 CPU under Android, I wonder if anyone would want that as it will increase temperatures enormously.
I've seen my phone give a warning already that the system was overheating by just running BOINC and a navigation app together, I think that would happen quite a lot more when using special SIMD registers.

Temps will be different on different cpu's. For example, on Intel's Z2520, with 4 SETI WU's it doesn't exceed 50 (Celsius). So, there is some gap for critical temps.
But, even if devs will add sse3 and it will magically increase the perfomance by 50%, there will be not 6 GigaFlops for (nopie) and 52 GF for (pie) but 9 and 78 respectively. Probably, not worth the effort.
But, I'd give at a try to crunch such sse units.