HP 48gII Advanced User's Reference Manual page 587

Flag
– Internal use only. (LN returns LN[ABS()] if set).
121
Internal use only. (0/0 occurred).
–
122
– Mode Switch.
123
Clear: Mode switch allowed.
Set: Mode switch not allowed.
– CAS Object Evaluation.
124
Clear: Non-algebraic CASCOMPEVAL is allowed.
Set: Non-algebraic CASCOMPEVAL is not allowed.
– Sign Determination Mode.
125
Clear: Accurate sign determination using polynomial Sturm sequences.
Set: Fast sign determination. Polynomial Sturm sequences are not used. Auto-
simplification of square roots canceled.
– Row Reduction Mode.
126
Clear: RREF done with last column.
Set: RREF done without last column.
– Not used.
127
–
128 Clear: Complex variables allowed.
Set (default): All variables are real.
System Flags (continued)
Description
System Flags C - 9