Stereo System User Manual

A - 180 DSP96002 USER’S MANUAL MOTOROLA
GETEXP Extract Exponent GETEXP
Operation:
Exponent(S) → D.L (parallel data bus move)
Assembler Syntax:
GETEXP S,D
(move syntax - see the Move instruction description.)
Description:
Extract the exponent of the single extended precision floating-point operand S and store it as an unbiased,
2’s complement, 32-bit integer in the low portion of D . The exponent value is decremented by the number
of shifts needed to normalize the mantissa if the floating-point number was denormalized.
As an example of the use of FGETMAN, GETEXP, and FSCALE; consider decomposing a floating-point
number into its mantissa and unbiased exponent and then recreating the original floating-point number.
FGETMAN D0, D1 ;extract normalized mantissa
GETEXP D0,D2 ;extract unbiased exponent
MOVE D2.L, D2.H ;move unbiased exponent
FSCALE.S D2.H, D1 ;scale original mantissa
The following table lists the results for some special cases:
Source operand Result
+/- infinity $7FFFFFFF
+/- zero $80000000
SNaN or QNaN $FFFFFFFF
Input Operand(s) Precision: SEP Floating-Point.
Output Operand Precision: 32-bit integer.
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 the source operand is infinity. Cleared otherwise.
LR - Not affected.
–
R - Not affected.
A - Not affected.