[CJefferson]

I didn't know about the innaccuracies in sin/cos, good to know, I'll remember that, but I usually wouldn't use those in a physics engine (and now I certainly won't).

The other stuff, different compiling levels, changing the floating point rounding mode, does indeed change results, but that wouldn't effect a single compile of a program running on different machines.

[strainer]

I maintain a javascript PRNG which relies on basic floating point math operations, addition and multiplication. Its test page here (https://strainer.github.io/Fdrandom.js/) displays a warning if it doesn't hit expected value 1 million rnds after default seeding. I've not found any computer or phone fail that basic compliance test yet. Differences in trig functions strikes me as more matter of Math library compliance that floating point unit, im not sure but would be hopeful these are fairly well standardised across javascript engines.