Floating-Point IP Cores User Guide

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Date 5/05/2023
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10.3. ALTFP_LOG Truth Table

This table lists the truth table for the natural logarithm operation.
Table 59.  Truth Table for Natural Logarithm Operations
DATA[] SIGN BIT RESULT[] Zero NaN
Normal 0 Normal 0 0
Normal 1 NaN 6 0 1
1 7 0 Zero 1 0
Denormal 8 0 Negative Infinity 0 0
Zero 9 0/1 Negative Infinity 0 0
Infinity 0 Positive Infinity 1 0
NaN X NaN 0 1
6 The natural logarithm of a negative value is invalid. Therefore, the output produced is a NaN.
7 The “1” in this case is equivalent to In 1.
8 The value of positive denormalized numbers is a value that approximates zero, and the output produced is a negative infinity number.
9 The zero in this case represents zero special case of the IEEE standard. It is not equivalent to In 0, but instead approximates to it.