Hi Bill,
On Mon, Mar 13, 2017 at 01:11:01PM -0500, Bill Schmidt wrote:
> Index: gcc/doc/extend.texi
> ===================================================================
> --- gcc/doc/extend.texi (revision 246014)
> +++ gcc/doc/extend.texi (working copy)
> @@ -948,10 +948,28 @@ names can be used together with @code{_Complex} to
> types.
>
> As an extension, GNU C and GNU C++ support additional floating
> -types, @code{__float80} and @code{__float128} to support 80-bit
> -(@code{XFmode}) and 128-bit (@code{TFmode}) floating types; these are
> -aliases for the type names @code{_Float64x} and @code{_Float128}.
> -Support for additional types includes the arithmetic operators:
> +types, which are not supported by all targets.
> +@itemize @bullet
> +@item @code{__float128} is available on i386, x86_64, IA-64, and
> +hppa HP-UX, as well as on PowerPC 64-bit GNU/Linux targets that enable
> +the vector scalar (VSX) instruction set. @code{__float128} supports
> +the 128-bit floating type. On i386, x86_64, PowerPC, and IA-64
> +other than HP-UX, @code{__float128} is an alias for @code{_Float128}.
> +On hppa and IA-64 HP-UX, @code{__float128} is an alias for @code{long
> +double}.
__float128 (-mfloat128) does not require 64-bit PowerPC, only hardware
support (-mfloat128-hardware) requires it (and only because we haven't
implemented it for 32-bit).
Segher
