HP aC++/HP C Programmer's Guide (B3901-90036; A.06.26; September 2011)

-fpeval
-fpeval=precision
The -fpeval option specifies the minimum precision to use for floating-point expression
evaluation. This option does not affect the precision of parameters, return types, or
assignments.
The defined values for precision are:
float Evaluates floating-point expressions and constants in their semantic type.
double Evaluates float operations and constants using the range and precision
of double, and evaluates all other floating-point expressions and constants
in their semantic type.
extended Utilizes hardware support of these floating-point registers for optimum
speed in floating-point computations. Evaluates float and double
constants and expressions using the range and precision of the extended
type, and evaluates all other floating-point expressions in their semantic
type. Though this option provides greater precision than double, it does
not provide greater speed than double or float.
The default is -fpeval=float.
-fpevaldec
-fpevaldec=precision
The -fpevaldec option specifies the minimum precision to use for decimal floating-point
expression evaluation. The possible values for precision are _Decimal32,
_Decimal64, and _Decimal128. This option does not affect the precision of
parameters, return types, or assignments.
The default is -fpevaldec=_Decimal32.
-[no]fpwidetypes
-[no]fpwidetypes
The -[no]fpwidetypes option enables [disables] extended and quad floating-point
data types. quad is equivalent to long double. This option also enables __float80
prototypes. The compiler defines _FPWIDETYPES when -fpwidetypes is in effect.
The default is -nofpwidetypes.
+decfp
The +decfp option enables full decimal floating-point functionality according to the
ISO/IEC C draft Technical Report (http://www.open-std.org/jtc1/sc22/wg14/
www/docs/n1312.pdf )
Decimal floating-point is also supported in C++ compilation mode.
Floating-Point Processing Options 49