Motorola DSP Developer's Kit

abs-r.asm

Y = mot###_abs(X)

Description

This function returns the absolute value of the input real vector X

Input/Output

Input: Real vector X (elements of X are real data)

Output: Real vector Y

Algorithm

for ( i=0; i<size(X); i++)
{    Y[i] = abs(X[i]);    }

Note    abs is an assembly instruction of the DSP56K instruction set

Memory& Register

Memory allocation and register usage:

• Start address of real vector X is defined in symbol IN
• Size of vector X is stored in register R7
• Start address of vector Y is defined in symbol OUT

Status Register

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

Data Size Limit

The length of vector X is limited by the size of available continuous data memory.

Data Range Limit

The input vector X 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

In the case of DSP563 and DSP566, there are 4 cycles for each element of input data.

Alphabetical List of Assembly Files

abs-c.asm