By: rwessel (rwessel.delete@this.yahoo.com), December 20, 2020 11:28 am
Room: Moderated Discussions
Konrad Schwarz (no.spam.delete@this.no.spam) on December 20, 2020 8:47 am wrote:
> anon (an.delete@this.n.com) on December 18, 2020 8:29 am wrote:
> > I read that C2X (the next C language revision) will add support for decimal floating point.
> > I know that POWER and SPARC CPUs have hardware support for decimal FP,
> > but are there any plans to include it on future x86 or ARM CPUs?
>
> The x87 supports a decimal floating point format, but I don't know if it is compatible to IEEE decimal floating
> point; the x87 format is a sign bit followed by 18 BCD digits and no exponent, so I expect not.
The x87 supports an integer decimal format for loads and stores (it converts them to/from a normal 80-bit temp real). Similar to the x87 support of loading and storing integers (the integer side also supports some load+op formats, which the BCD side does not). Both FBLD and FBSTP are very slow.
The format has no relation to IEEE DFP.
> anon (an.delete@this.n.com) on December 18, 2020 8:29 am wrote:
> > I read that C2X (the next C language revision) will add support for decimal floating point.
> > I know that POWER and SPARC CPUs have hardware support for decimal FP,
> > but are there any plans to include it on future x86 or ARM CPUs?
>
> The x87 supports a decimal floating point format, but I don't know if it is compatible to IEEE decimal floating
> point; the x87 format is a sign bit followed by 18 BCD digits and no exponent, so I expect not.
The x87 supports an integer decimal format for loads and stores (it converts them to/from a normal 80-bit temp real). Similar to the x87 support of loading and storing integers (the integer side also supports some load+op formats, which the BCD side does not). Both FBLD and FBSTP are very slow.
The format has no relation to IEEE DFP.
