IQmath Library

IQNmpy
IQ Multiplication(IQN*IQN)
Description
Declaration
This “C” compiler intrinsic multiplies two IQ number. It does not perform
saturation and rounding. In most cases, the multiplication of two IQ
variables will not exceed the range of the IQ variable. This operation
takes the least amount of cycles and code size and should be used most
often.
Global IQ intrinsic (IQ format = GLOBAL_Q)
_iq _IQmpy(_iq A, _iq B)
Q format specific IQ intrinsic (IQ format = IQ1 to IQ30)
_iqN _IQNmpy(_iqN A, _iqN B)
Input Format
Global IQ intrinsic (IQ format = GLOBAL_Q)
Input “A” & “B” are IQ number in GLOBAL_Q format
Q format specific IQ intrinsic (IQ format = IQ1 to IQ30)
Input “A” & “B” are IQ number in IQN format
Output Format
Global IQ intrinsic (IQ format = GLOBAL_Q)
Result of multiplication in GLOBAL_Q format
Q format specific IQ intrinsic (IQ format = IQ1 to IQ30)
Result of multiplication in IQN format.
Usage
Example 1:
Following code computes "Y = M*X + B" in GLOBAL_Q format with no
rounding or saturation:
_iq Y, M, X, B;
Y = _IQmpy(M,X) + B;
Example 2:
Following code computes "Y = M*X + B" in IQ10 format with no rounding
or saturation, assuming M, X, B are represented in IQ10 format:
_iq10 Y, M, X, B;
Y = _IQ10mpy(M,X) + B;
©Texas Instruments Inc., June 2002 23