Motorola DSP96002 User Manual
Page 56
MOTOROLA
DSP96002 USER’S MANUAL
5 - 3
is not aware that the data is represented in a floating point format. The range of the unbiased exponent, E,
is every integer between E
min
and E
max
, inclusive (-E
min
<E<E
max
). For single precision (SP), E
min
= -126
while E
max
= +127; for double precision (DP), E
min
= -1022 while E
max
= +1023. For both SP and DP, E
min
-
1 is reserved to encode
±
0 and denormalized numbers while E
max
+1 is used to encode
±∞
and NaN’s.
5.2.2.1
IEEE Single Precision Real Memory Format Summary
23-Bit
Fraction
11-Bit
Exponent
S
52-Bit
Fraction
8-Bit
Exponent
S
SINGLE REAL
DOUBLE REAL
Sign of Significand
Sign of Significand
Figure 5-3. Memory Format for floating-point Operands
31 30
23 22
0
63 62
52 51
0
Field Size (in bits):
s = Sign ............... 1
e = Biased Exponent .... 8
f = Fraction ........... 23
Interpretation of Sign:
Positive Mantissa: s = 0
Negative Mantissa: s = 1
Normalized Numbers:
Represents real numbers in the form (-1)
s
x 2
(E+127)
x 1.f
E ........................ unbiased exponent -126 < E < +127
Bias of e .............. +127 ($7F)
e = E + bias .......... 0 < e < 254 ($FE)
f ...................... Zero or Non-Zero
Mantissa................ 1.f
Fraction
S
Biased
Exponent
31 30
23 22
0
31
0