ARM had a wacky byte-swapped original floating point format and then an FP accelerator (in the Acorn days) called FPA that used that format. At some point, the ARM community switched to standard IEEE FP, and then they added the VFP FPUs that we use today. Neon is the SIMD extension added later.
RISC OS has a version of BBC BASIC compiled for software ARM FP format, another for the rare Archimedes with the FPA accelerator, and a third version using the VFP and IEEE that you see on modern ARM.
