gcc-arm_elf/eabi/none-eabi tutorial?

I am quit new around arm and gcc and didn't find a tutorial explaining
the differences between arm-elf  arm-eabi  arm-none-eabi tool chains
options.
Is there someone who can teach me (us?) regarding this topic?
If yes, could you add an explanation on how these different tool chain
options interact with floating point behavior on arm family? (I am using
an Arm966E, STR912 precisely, then without VFP).
Many thanks in advance.
Joel