Overflow, Underflow, and Invalid Modes

Versal ACAP DSP Engine Architecture Manual (AM004)

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1.2.1 English

When the overflow condition is detected, the output is infinity and the overflow flag is raised. In Multiplication and Addition operations, overflow can occur only during multiplication or addition of two finite normal numbers that results exceed the maximum normalized value (32’h7F7FFFFF or 32’hFF7FFFFF). Similarly, underflow can occur only during operation of two finite normal numbers resulting in a non-zero value less than the minimum normal number (32’h00800000 or 32’h80800000 such as a subnormal value or exponent rollover). Anything resulting in a non-zero number less than the minimum normalized value triggers an underflow.

Invalid operations that set invalid status flag include the following:
  1. Any operation with one or more signaling NaN inputs
  2. Addition of infinities with opposite signs
  3. Multiplication of zero and infinity