Program Memory: Program memory contains the user’s stored program.   Capacity: 100 locations   Top is above first location.   Bottom is last location. Pointer: The pointer is an internal part of the calculator. It determines which memory location is executed or displayed. Codes: In W/PRGM mode. keystrokes are stored in memory as codes: Top of memory code is 00 00. The codes for keys 0-9 are 00-09. For other keys, a code denotes a row and a column. Example: Code for R/S (row 8, column 4) is 84. Merged Codes: Program codes for the following are merged with their respective prefix codes: LSTX, NOP, x y, R , R , x≠y, x≤y, x=y, x>y, and 1, . . . , 8 when prefixed by STO or RCL.   Example: gLSTX in program mode is merged and displayed as 35 00; STO 5 as 33 05, etc. Note that STO 9 and RCL 9 are not merged. Single Step:   In W/PRGM mode, SST advances the program pointer to the next memory location, displaying the code. Repeated use of the key enables you to review a program and to position the pointer for editing.   In RUN mode, SST executes the program step denoted by the program pointer. In the case of single stepping a call to a user defined function, (A, . . . , E), the entire function executes (as one step) before returning control to the keyboard.