Stereo System User Manual

A - 166 DSP96002 USER’S MANUAL MOTOROLA
FSEEDR Square Root FSEEDR
Reciprocal Approximation
Operation:
Approximation(1/SQRT(S)) → D
Assembler Syntax:
FSEEDR S,D
Description:
Take the contents of the specified source operand S, determine an approximation to sqrt(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 square root algorithms.
The table below describes the operation of the FSEEDR instruction:
Source Operand Result
SNaN or QNaN QNaN
less than zero QNaN
+/- zero +/- zero
+ denormalized normalized, then FSEEDR approximation
+ normalized FSEEDR approximation
+ infinity + infinity
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.