Texas Instruments TMS320C2x, User Manual

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clock
7-28
Processor Time
clock
Syntax #include <time.h>
clock_t clock (void);
Defined in clock.c in rts.src
Description The clock function determines the amount of processor time used. It returns
an approximation of the processor time used by a program since the program
began running. The time in seconds is the return value divided by the value
of the macro CLOCKS_PER_SEC.
If the processor time is not available or cannot be represented, the clock func-
tion returns the value of
− 1.
Note: Writing Your Own Clock Function
The clock function is target-system specific, so you must write your own
clock function. You must also define the CLOCKS_PER_SEC macro accord-
ing to the units of your clock so that the value returned by clock( ) (number
of clock ticks) can be divided by CLOCKS_PER_SEC to produce a value in
seconds.
For more information about the functions and types that the time.h header
declares and defines, see section 7.2.12, Time Function (time.h) on page 7-11.
Cosine
cos
Syntax #include <math.h>
double cos (double x);
Defined in cos.c in rts.src
Description The cos function returns the cosine of a floating-point number x. The angle x
is expressed in radians. An argument with a large magnitude might produce
a result with little or no significance.
Example
double radians, cval; /* cos returns cval */
radians = 3.1415927;
cval = cos(radians); /* return value = −1.0 */