[ia64-abi] Re: New issue: __int64 and friends

[Cary Coutant]

>> I think the current IEEE standard (IEC 60559:1989) specifies the
>> layout of the 128 bit floating point type. Without checking
>> (ie. taking the format from CORBA instead), this should be sign +
>> 15bit-exponent + 112bit-mantissa, the exponent being with a bias of
>> 16383.
>
>I only have IEEE-754 (1985), which doesn't specify.  If there's a
>standardized format somewhere (preferably IEEE, but CORBA's a fine
>backup), that's probably what we should use.  Does someone have a solid
>reference?

The common runtime document does specify the layout of __float128 (in 
footnote 3 to Table 4-1):

    ...A quad-precision floating-point number is a 128-bit
    quantity with a sign bit, a 15-bit biased exponent, and
    a 112-bit mantissa with an implicit integer bit.

This description nails down (I believe) all the parameters allowed the 
implementation by the IEEE standard.

-cary