5.10 Additional Floating Types
As an extension, the GNU C compiler supports additional floating
__float128 to support 80bit
XFmode) and 128 bit (
TFmode) floating types.
Support for additional types includes the arithmetic operators:
add, subtract, multiply, divide; unary arithmetic operators;
relational operators; equality operators; and conversions to and from
integer and other floating types. Use a suffix w or W
in a literal constant of type
__float80 and q or Q
_float128. You can declare complex types using the
corresponding internal complex type,
typedef _Complex float __attribute__((mode(TC))) _Complex128; typedef _Complex float __attribute__((mode(XC))) _Complex80;
Not all targets support additional floating point types.
__float128 types are supported on i386, x86_64 and ia64 targets.