I was asked about the expected performance of my upcoming rpix86 emulator on the Atari800 thread. Instead of hijacking that thread, I think it would be better for me to create a new thread specifically for rpix86, so here it is.

The performance expectation for a non-overclocked Raspberry Pi currently looks to be around a 486/20 machine. This is somewhat slower than what I think RPi should be capable of, so there are probably some bottlenecks in my code that I just haven't found yet. Or perhaps simply running the Linux OS causes a big hit on the available CPU power. The DS2x86 version for a 400MHz MIPS processor (without an operating system) runs Doom at 5.1 fps, and the current rpix86 version (on Raspbian Wheezy) only at 5.5 fps, even though the ARM processor should be almost 2x more efficient per MHz than the MIPS processor. My Android tablet with a 1.3GHz quad-core processor runs Doom in ax86 at 27.5 fps, so I think 5.5 fps is slower than what it should be.
My plan is to run some cycle counter tests in the near future to see where the performance problems are. Also my CPU core is still using plain ARMv5 assembly, so using some of the new instructions for ARMv6 could bring some performance improvements.
Edit:
rpix86 version 0.19 released June 28th, 2015!
You can download the new version from the Raspberry Pi store: http://store.raspberrypi.com/projects/rpix86 or alternatively directly from my web pages: http://rpix86.patrickaalto.com/rdown.html
New users, be sure to read Ben Garrett's tutorial for rpix86 installation and usage at http://ipggi.wordpress.com/2013/04/23/r ... r-computer
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