AT&T 6300 Programmer's Manual page 76

Variable Types
3-18
OVERFLOW
If, during the evaluation of an expression,
division by zero is encountered, the "Division
by zero" error message is displayed, machine
infinity (the largest number that can be
represented in floating-point format) with the
sign of the numerator is supplied as the result
of the division, and execution continues. If the
evaluation of an exponentiation operator
results in zero being raised to a negative
power, the "Division by zero" error message
again is displayed, positive machine infinity is
supplied as the result of the exponentiation,
and execution continues.
If overflow occurs, the "Overflow" error
message is displayed, machine infinity with
the algebraically correct sign is supplied as
the result, and execution continues.