CC78K4 Datasheet, PDF (236/523 Pages) NEC – CC78K4 Ver.2.30 or Later, C Compiler Language

CHAPTER 10 LIBRARY FUNCTIONS
7-4 atan2
Mathematical Functions
FUNCTION
atan2 finds atan of y/x.
HEADER
math.h
FUNCTION PROTOTYPE
double atan2 (double y, double x);
Function
atan2
Arguments
x ... Numeric value to perform
operation
y ... Numeric value to perform
operation
Return Value
Normal ... atan of y/x
When both x and y are 0 or
y/x is the value that cannot be
expressed, or either x or y is
NaN and both x and y are ± ∞
... NaN
Non-normalized number ...
When underflow occurs
EXPLANATION
• atan (range between –π and +π) of y/x is calculated. When both x and y are 0 or y/x is the value that cannot
be expressed, or when both x and y are infinite, NaN is returned and EDOM is set to errno.
• If either x or y is non-numeric, NaN is returned.
• If an underflow occurs as a result of the operation, a non-normalized number is returned.
236
User’s Manual U15556EJ1V0UM