-QSfast, -QSfastd - Provide Backward Compatibility
9/7/2007
These options, -QSfast and -QSfastd provide backward compatibility. -QSfastd is the default.
The device compilers support full IEEE compliant hardware operations including the use of denormal operands. This allows the compiler to default to use of the Renesas SuperH SH-4 hardware instructions for both single and double precision floating-point operations.
The -QSfast option causes the compiler to call CRT emulation routines for all floating-point operations.
The -QSfast option allows the compiler to use single precision SH-4 floating-point instructions. It will also generate a warning if the compiler finds a double floating point constant.
Do not use double constants when performance is a consideration, because double constants can unnecessarily promote an operation-type from single to double precision.
Note that floating-point constants default to type double. You may specify single precision floating point constants with a floating suffix f or F such as 3.14159f.
The default -QSfastd option allows the compiler to use single and double precision SH-4 floating-point instructions.
The compiler does not generate warnings for double constants when you specify -QSfastd. The -QSfastd command line option may cause the compiler to produce slightly larger code.