IQmath Library

C-Callable ASM Interface
C-Callable ASM Interface
Declaration
Global IQ function (IQ format = GLOBAL_Q)
_iq _IQcos(_iq A)
Q format specific IQ function (IQ format = IQ1 to IQ29)
_iqN _IQNcos(_iqN A)
Input Format
Global IQ function (IQ format = GLOBAL_Q)
Input argument is in radians and represented as fixed-point number in
GLOBAL_Q format.
Q format specific IQ function (IQ format = IQ1 to IQ29)
Input argument is in radians and represented as fixed-point number in
IQN format (N=1:29).
Output Format
Global IQ function (IQ format = GLOBAL_Q)
This function returns the cosine of the input argument as fixed-point
number in GLOBAL_Q format.
Example
Q format specific IQ function (IQ format = IQ1 to IQ29)
This function returns the cosine of the input argument as fixed-point
number in IQN format (N=1:29)
The following example obtains the cos ( 0.25×π )
Q29 format in the IQmath header file.
=0.707 assuming that GLOBAL_Q is set to
#include
*/
#define PI 3.14156
/* Header file for IQmath routine
_iq in1, out1;
_iq29 in2 out2;
void main(void )
{
in1=_IQ(0.25*PI); /* in= 0.25 ×π × 2
29 = 1921FB54h
*/
out1=_IQcos(in1); /* out1= cos( 0.25×π ) × 2
29 = 16A09E66h
*/
in2=_IQ29(0.25*PI); /* in2= 0.25 ×π × 2
29 = 1921FB54h
*/
out2=_IQ29cos(in2); /* out2= cos( 0.25×π ) × 2
29 = 16A09E66h
*/
}
©Texas Instruments Inc., June 2002 41