half datatype?

[Walter Bright]

On 11/18/2012 4:23 PM, Manu wrote:
> Actually, they probably will. People using it will need to use it regardless of
> how it's implemented. Hardware support it great when available, but
> realistically, it's used when processing data for execution on another processor
> that does support it in hardware (typically a GPU). Use of fp16 is probably not
> optional; it doubles your bandwidth wherever the loss of precision is acceptable.

Doing implicit conversions on them implies doing them on the x86 CPU, which has 
no hardware support for the type. All operations would require software emulation.

If it is a storage-only format, then what role do implicit conversions play?