On the contrary, I expected the Nintendo DS SDK to be well optimized, performance of memcpy can be critical on such a constrained hardware. And it was optimized, just not with the best tricks.
I got the prefetching trick from Intel source code, except that I replaced the PLD instruction by a simple dummy load.
And about strlen, you'd be surprised, some implems are very good, and some are not, depends on the compiler and the library. I've ran benchmarks, I was surprised too.
To be honest, I don't really need super fast strlen, but I was curious and also learning to write fast SIMD code, basic string handling is a nice exercise.
I think this expectation doesn't vibe with my understanding of how people used to think about embedded or consoles. You shipped them and they were done. The games industry was also often trying to ship quickly. Small teams too. Latest tweaks to memcpy or fine tuning or revisiting the finer points of an already adequate SDK is low priority.
By contrast, many more people are updating optimizations to GCC or clang for arm, more frequently and over a longer timeframe.
You're probably right about consoles, and I was surprised to be wrong, but I checked, just to be sure.
GCC and Clang are very nice compilers, but they are a different thing than the std lib. glibc, musl, the Windows C Runtime, iOS, Android, all have different implementations, sometimes outdated.
Of course I have data, do you think I am pulling benchmarks out of a hat?
But I have not published those benchmarks, if this is what you're asking, the Nintendo thing I am afraid I cannot reproduce easily as I no longer have this devkit on hand.
About the strlen benchmark, this is something I've done a few years ago, that could be easy to run again, but I am not sure this is worth the effort just to convince a random dude on the internet...
I got the prefetching trick from Intel source code, except that I replaced the PLD instruction by a simple dummy load.
And about strlen, you'd be surprised, some implems are very good, and some are not, depends on the compiler and the library. I've ran benchmarks, I was surprised too.
To be honest, I don't really need super fast strlen, but I was curious and also learning to write fast SIMD code, basic string handling is a nice exercise.