RealView Compilation Tools Compiler Reference Guide - ARM ...

C and C++ Compiler Implementation Limits
Table D-4 describes other characteristics of floating-point numbers. These constants are
also defined in the float.h include file.
Table D-4 Other floating-point characteristics
Constant Meaning Value
FLT_RADIX Base (radix) of the ARM floating-point number representation 2
FLT_ROUNDS Rounding mode for floating-point numbers (nearest) 1
FLT_DIG Decimal digits of precision for float 6
DBL_DIG Decimal digits of precision for double 15
LDBL_DIG Decimal digits of precision for long double 15
FLT_MANT_DIG Binary digits of precision for type float 24
DBL_MANT_DIG Binary digits of precision for type double 53
LDBL_MANT_DIG Binary digits of precision for type long double 53
FLT_EPSILON Smallest positive value of x that 1.0 + x != 1.0 for type float 1.19209290e–7F
DBL_EPSILON Smallest positive value of x that 1.0 + x != 1.0 for type double 2.2204460492503131e–16
LDBL_EPSILON
Smallest positive value of x that 1.0 + x != 1.0 for type long
double
2.2204460492503131e–16L
Note
• When a floating-point number is converted to a shorter floating-point number, it
is rounded to the nearest representable number.
• Floating-point arithmetic conforms to IEEE 754.
D-6 Copyright © 2007, 2010 ARM Limited. All rights reserved. ARM DUI 0348A
Non-Confidential