Motorola DSP Developer's Kit

conv-r.asm

C = mot###_conv( A,B )

Description

This function convolves vectors A and B, where both A and B are real vectors

Input/Output

Input: Real vector A, and real vector B

Output: Real vector C

Algorithm

LengthC = LengthB + LengthA - 1

for ( i = 1; i  <= LengthC; i ++ ) {
if ( i <= LengthA ) {
   for ( j = 1; j <= i; j ++ ) {
       C[i] += A[j] * B[i - j + 1]; }}
else {
   for ( j = i - LengthA; j <= LengthA - 1; j ++ ) {
       C[i] += A[j + 1] * B[i - j];
     }}}

    Memory & Register

Memory allocation:

In X memory:

• X:(#INA) stores the start address of vector A
• X:(#INA+LENGTH(A)) stores the start address of vector C

In Y memory:

• Y:(#INB) stores the start address of vector B

Register usage:

• R2 stores the length of vector A
• R7 stores the length of vector C
• R0 stores the index of vector A
• R4 and R5 store the index of vector B
• R3 stores the index of vector C
• R1, R2, and R6 are used as loop control
• R2-1 -> M5, assume M{0,1,2,3,4,6,7} = $ffffff

Status Register

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

Data Size Limit

The maximum length of vector A and B can't be larger than 1/3 of the continuous available data memory size.

Data Range Limit

The input data vector range is [-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:

angle-c.asm

conv-c.asm