Motorola DSP Developer's Kit

sum-c.asm

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

Description

This function returns the sum of the complex input elements of X

Input/Output

Input: Complex vector X (includes the real part Xr, and the imaginary part Xi)

Output: scalar y (includes the sum of the real data of the element yr, and the sum of the imaginary data of the element yi)

Algorithm

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

Memory & Resister

Memory allocation:

• X memory label IN stores the start address of the input of real vector X.
• X memory label IN_REAL stores the start address of the real data of the input vector
• Y memory label IN_IMAG stores the start address of the complex (imaginary) data of the input vector

Register usage:

• Register A is used for the result of the real part
• Register B is used for the result of the imaginary part
• R7 is used for the number of items in the array

Status Register

The assembly function sum-c.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

The value of input vector X must be between -1.0 and +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:

sum-r.asm

xcorr-r.asm