Minecraft's Far Lands aren't actually related to floating point precision, although movement near the Far Lands is affected.

My understanding of what causes the Far Lands isn't that great, but I think it's caused by one of six or eight shorts overflowing in the generation algorithm.

Edit: It seems I needed to read more of the Minecraft Wiki link for the Farlands. https://minecraft.gamepedia.com/Far_Lands#Cause covers it much better than I could.