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Fseedd reciprocal approximation fseedd – Motorola DSP96002 User Manual

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DSP96002 USER’S MANUAL

MOTOROLA

FSEEDD

Reciprocal Approximation

FSEEDD

Operation:

Approximation(1/S)

D

Assembler Syntax:

FSEEDD S,D

Description:

Take the contents of the specified source operand S, determine an approximation to 1.0/S, and store the

result in the destination operand D. The 9 MSBs of the destination significand are determined by using a

lookup ROM. The remaining bits of the significand are zeroed. This instruction is useful for initializing

floating-point divide algorithms.

The table below describes the operation of the FSEEDD instruction:

Source Operand

Result

SNaN or QNaN

QNaN

+/- zero

+/- infinity

+/- denormalized

normalized, then FSEEDD approximation

+/- normalized

FSEEDD approximation

+/- infinity

+/- zero

Input Operand(s) Precision: SEP Floating-Point.

Output Operand Precision: SEP Floating-Point.

CCR Condition Codes:

C

- Not affected.

V

- Not affected.

Z

- Set if result is zero. Cleared otherwise.

N

- Set if result is negative. Cleared otherwise.

I

- Set if result is infinity. Cleared otherwise.

LR

- Not affected.

R

- Not affected.

A

- Not affected.