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Chapter 2
C and C++ Source-Level Optimizations
9
Software Optimization Guide for AMD64 Processors
25112
Rev. 3.06
September 2005
2.1
Declarations of Floating-Point Values
Optimization
When working with single precision (
float
) values:
•
Use the
f
or
F
suffix (for example,
3.14f
) to specify a constant value of type
float
.
•
Use function prototypes for all functions that accept arguments of type
float
.
Application
This optimization applies to:
•
32-bit software
•
64-bit software
Rationale
C and C++ compilers treat floating-point constants and arguments as double precision (
double
)
unless you specify otherwise. However, single precision floating-point values occupy half the
memory space as double precision values and can often provide the precision necessary for a given
computational problem.
memory space as double precision values and can often provide the precision necessary for a given
computational problem.