TMS320C4X Datasheet, PDF (104/726 Pages) Texas Instruments – Digital Signal Processing Solutions

Floating-Point Formats
- If s = 1, form the mantissa by writing 10. and appending the bits in the frac-
tion field after the binary point.
For example, if f = 10100000000₂, then man = 10.10100000000₂.
S
Fraction
1.1 0 1 0 0 0 0 0 0 0 0
Rewrite the mantissa as:
Mantissa
1 0.1 0 1 0 0 0 0 0 0 0 0
5.3.4.2 Step 2: Shift the Decimal Point in the Mantissa and Convert to Decimal
If the exponent (e) has a positive value, then you shift the binary point e places
to the right.
If the exponent (e) has a negative value, then you shift the binary point e places
to the left.
For example, if e = 2₁₀ and the man = 01.11000000000₂, then the shifted man-
tissa becomes 0111.000000000₂, which is equivalent to 7 in decimal.
If, on the other hand, e = –2₁₀ and man =01.10000000000₂, then the shifted
mantissa becomes .0110000000000₂, which is equivalent to 3/8 in decimal.
The following examples illustrate how you can obtain the equivalent floating-
point value of a number in ’C4x floating-point format. Each of the examples
uses the single-precision floating point format.
Example 5–1. Positive Number
0240000
0
0000 0010 0100 0000 0000 0000 0000 0000
Exponent =
Sign
=
Fraction =
Value =
0000 0010₂ = 2
0
.10000₂
01.1₂ × 2² = 0110₂. = 6
Hex value
Binary value
Fraction
Implied
Sign
Data Formats and Floating-Point Operation
5-9