Motorola DSP Developer's Kit

sort-r1.asm

Y = mot###_sort(X)

Description

This function sorts real elements of input real vector X

Input/Output

Input: Real vector X

Output: Real vector Y

Algorithm

The heap sort algorithm will be used.

#define IN X:$0
#define OUT X:$0
heapsort(Length)
{
    for( i = Length/2; i>=1; --i)
        sift (i, Length);/* set up initial heap */
    for( k = Length; k >= 2; k--)
    {
        Intervalue = r[1];
        r[1] = r[k];
        r[k] = Intervalue;
        sift(1, k-1);
    }
}

sift (from, Length)
{
    Intervalue = r[from];
    k = from;
    j = 2 * from;
    while (j <= Length)
    {
    if ((j< Length) && (r[j] < r[j+1]))
        j++;
    if(Intervalue < r[j])
    {
        r[k] = r[j];
        k = j;
        j *= 2;
    }

    else
        j = Length + 1;/* return */
    r[k] = Intervalue;
}

Memory & Register

Memory allocation:

X memory:

• Label IN stores the address of the real input of vector X
• Label OUT stores the address of the real output of vector Y

Register usage:

• R7stores the number of items in the array

Status Register

The assembly function sort-1r.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.

round-c.asm

sort-r2.asm