Motorola DSP Developer's Kit

mean-c.asm

Motorola DSP Developer's Kit

mean-c.asm

[y] = mot###_mean( X )

This function returns the mean value of the elements in complex input vector X

Input/Output

Input: Complex vector X, which includes vector Xr (real part of input X) and vector Xi (imaginary part of input X)

Output: scalar y, which includes yr (the mean value of the real elements in X), yi (the mean value of the imaginary elements in X)

Algorithm

yr = yi = 0;
for(i=0; i<size; i++)
{
    yr += Xr[i];
    yi += Xi[i];
}
yr = div (yr, size);
yi = div (yi, size);

Memory & Register

IN start address of location of input complex vector X.

X memory IN_REAL start address of real data of X

Y memory IN_IMAG start address of imaginary data of X

Register X0 store number of items in the array

Register X1 store Result of mean value(real)

Register Y1 store Result of mean value(imaginary)

Register R7 store bits/word, used by division (24 for 56300,16 for 56600)

Status Register

The assembly function mean-r.asm does not explicitly set any status registers/bits during the function execution.

Data Size Limit

The length of vector X can't be larger than the continuous available data memory size.

Data Range Limit

Input data vector X range [-1.0, +1.0]

Precision

In the case of DSP563, precision is 23 bits.

In the case of DSP566, precision is 15 bits.

Performance Limit

DSP563:

DSP566:

mean-r.asm

min-1r.asm