RM 3 5 7 17 Float Types (GNAT Reference Manual)

### 6.10 RM 3.5.7(17): Float Types ¶

> “An implementation should support `Long_Float` in addition to `Float` if the target machine supports 11 or more digits of precision. No other named floating point subtypes are recommended for package `Standard`. Instead, appropriate named floating point subtypes should be provided in the library package `Interfaces` (see B.2).”

`Short_Float` and `Long_Long_Float` are also provided. The former provides improved compatibility with other implementations supporting this type. The latter corresponds to the highest precision floating-point type supported by the hardware. On most machines, this will be the same as `Long_Float`, but on some machines, it will correspond to the IEEE extended form. The notable case is all x86 implementations, where `Long_Long_Float` corresponds to the 80-bit extended precision format supported in hardware on this processor. Note that the 128-bit format on SPARC is not supported, since this is a software rather than a hardware format.