Indicates that the magnitude of a floating-point value is smaller than the minimum allowed
Enabled/Disabled status
Always enabled.
Result
The invalid floating-point value is set to 0 except for IEEE floating-point on z/OS, which has an undefined result.
Raised
When the magnitude of a floating-point number is smaller than the minimum allowed.
Notes
UNDERFLOW is not raised when equal numbers are subtracted. This is often called the significance error.
Because the expression X
(-Y) where Y>0 can be evaluated by taking the reciprocal of X
Y, the OVERFLOW condition might be raised in this case instead of the UNDERFLOW condition.
Other Information
- Abbreviation
- UFL
- Condition code
- 330
- Implicit action
- Prints a message and continues execution from the point at which the condition was raised; however, if the exception is raised
during the evaluation of an IEEE floating-point on z/OS, a message is printed and the ERROR condition is raised.
- Normal return
- Control returns to the point immediately following the point at which the condition was raised and the value resulting from
the operation that caused the UNDERFLOW condition is set to zero. However, if the exception was raised during the evaluation
of an IEEE floating-point on z/OS, the ERROR condition is raised.