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Technical Support
On-Line Manuals
Libraries and Floating Point Support Guide
Conventions and feedback
The ARM C and C++ libraries
The ARM C micro-library
Floating-point support
About floating-point support
The software floating-point library, fplib
Calling fplib routines
fplib arithmetic on numbers in a particular format
fplib conversions between floats, doubles, and int
fplib conversion between long longs, floats, and d
fplib comparisons between floats and doubles
fplib C99 functions
Controlling the ARM floating-point environment
Floating-point functions for compatibility with Mi
C99-compatible functions for controlling the ARM f
C99 rounding mode and floating-point exception mac
Exception flag handling
Functions for handling rounding modes
Functions for saving and restoring the whole float
Functions for temporarily disabling exceptions
ARM floating-point compiler extensions to the C99
Writing a custom exception trap handler
Example of a custom exception handler
Exception trap handling by signals
Using C99 signalling NaNs provided by mathlib (_WA
mathlib double and single-precision floating-point
Nonstandard functions in mathlib
IEEE 754 arithmetic
Basic data types for IEEE 754 arithmetic
Single precision data type for IEEE 754 arithmetic
Double precision data type for IEEE 754 arithmetic
Sample single precision floating-point values for
Sample double precision floating-point values for
IEEE 754 arithmetic and rounding
Exceptions arising from IEEE 754 floating-point ar
Ignoring exceptions from IEEE 754 floating-point a
Trapping exceptions from IEEE 754 floating-point a
Exception types recognized by the ARM floating-poi
Using the Vector Floating-Point (VFP) support libr
Functions for saving and restoring the whole floating-point environment
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Note
The following functionality requires you to select a floating-point
model that supports exceptions, such as --fpmode=ieee_full or --fpmode=ieee_fixed.
C99 provides the following functions to save and restore the entire floating-point environment:
void fegetenv(fenv_t *envp); void fesetenv(const fenv_t *envp);
The fegetenv() function stores the current
state of the floating-point environment into the fenv_t variable
provided. The fesetenv() function restores
the environment from the variable provided.
Like fesetexceptflag(), fesetenv() does
not call trap handlers when it sets the sticky flags for trapped
exceptions.
See also- Concepts
- Reference
Compiler Reference:
| Copyright © 2007-2008, 2011-2012 ARM. All rights reserved. | ARM DUI 0378D |
| Non-Confidential | ID062912 |
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| Home > Floating-point support > Functions for saving and restoring the whole floating-point environment |
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