Re: [PATCH] define WIDEST_HARDWARE_FP_SIZE on mips

[Geert Bosch <bosch at adacore dot com>]

On Mar 4, 2009, at 15:24, Richard Sandiford wrote:

> Geert said:
>
>  The Ada standard requires support for the widest hardware floating  
> point
>  format provided by the hardware. This type can be accessed by  
> declaring
>  your type as "type My_Float is digits System.Max_Digits". Various
>  routines for printing and type conversions use this type as well.
>
>  Ada does not allow a "type My_Float is digits X" where X >
>  System.Max_Digits, [...]
>
> so how does that apply to systems that don't have hardware floating  
> point?

This falls outside the language standard. The only requirement is that  
if Long_Float
is predefined, it is at least 11 digits (corresponds to double  
precision).
The interesting case is indeed when single precision floating-point is  
implemented
in hardware, while double precision is emulated.

As I indicated earlier, I think WIDEST_HARDWARE_FP_SIZE should indeed  
reflect the truth
(so, should be 0 for software float, or 32 if only single precision is  
supported in HW).
For Ada, we'll then replace uses of WIDEST_HARDWARE_FP_SIZE with an  
expression that takes
the maximum of long_float_type_size and WIDEST_HARDWARE_FP_SIZE for  
the size of Long_Long_Float.

  -Geert