Appendix D: Common Errors96
13. Using DSZ in a program and forgetting to initialize register R8 to the proper value.
14. Calculating f(x,y) with the operands reversed.
15. Losing program and data by inadvertently switching the calculator off, by unplugging the battery charger, or by plugging in the battery charger.
16. Causing improper return from a defined function because multi-level nesting was attempted. Proper usage is as follows: a program can call a function but that function must return control to the caller before another function can be executed. See description of RTN in section 4.
17. Using CLx to put zero into X only to have it overwritten by a subsequent operation, because CLx disables the stack lift. Use 0 to put zero into X.