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
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): Interpretation of Sign: Normalized Numbers: Represents real numbers in the form (-1) s x 2 (E+127) x 1.f E ........................ unbiased exponent -126 < E < +127 Fraction S Biased Exponent 31 30 23 22 0 31 0
s = Sign ............... 1
e = Biased Exponent .... 8
f = Fraction ........... 23
Positive Mantissa: s = 0
Negative Mantissa: s = 1
Bias of e .............. +127 ($7F)
e = E + bias .......... 0 < e < 254 ($FE)
f ...................... Zero or Non-Zero
Mantissa................ 1.f