Developer Guide and Reference

Contents

pc, Qpc

Enables control of floating-point significand precision.

Syntax

Linux:
-pc
n
macOS:
-pc
n
Windows:
/Qpc
n
Arguments
n
Is the floating-point significand precision. Possible values are:
32
Rounds the significand to 24 bits (single precision).
64
Rounds the significand to 53 bits (double precision).
80
Rounds the significand to 64 bits (extended precision).
Default
-pc80
or
/Qpc64
On Linux*
and
macOS*
systems, the floating-point significand is rounded to 64 bits.
On Windows* systems, the floating-point significand is rounded to 53 bits.
Description
This option enables control of floating-point significand precision.
Some floating-point algorithms are sensitive to the accuracy of the significand, or fractional part of the floating-point value. For example, iterative operations like division and finding the square root can run faster if you lower the precision with the this option.
Note that a change of the default precision control or rounding mode, for example, by using the
[Q]pc32
option or by user intervention, may affect the results returned by some of the mathematical functions.
Alternate Options
None

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804