Section 5: Storing and Recalling Numbers and ALPHA Strings73
Keystrokes Display    
g ARCL 01 6.8000E94 _   The number now appears as ALPHA characters and is not valid for arithmetic functions. The exponent is marked with E.
g CLA       
 6.8000 94
  The original number is in X.
Defining Storage Register Configuration
As you read at the beginning of this section, you can control the amount of HP-41C memory that is allocated to both data storage registers and program memory. The SIZE function allows you to specify the number of data storage registers you wish to have allocated. Remember, your basic HP-41C has up to 63 data storage registers and you can add memory modules for a total of up to 319.
When you execute SIZE , the HP-41C prompts you for a three-digit number from 000 through 318.
If you attempt to increase the allocation of storage registers and there is not enough unused space in program memory for this increase, the HP-41C will display PACKING and then TRY AGAIN. After you execute SIZE again, if the HP-41C again displays PACKING and TRY AGAIN, this means that the reallocation is not possible until program instructions are deleted from program memory.
If you decrease the allocation of data storage registers, any information in reallocated data storage registers will be lost.
Any attempt to store or recall using a storage register that is not in the current allocation will result in the NONEXISTENT message in the display. For example, if the HP-41C has 17 storage registers allocated (R00 through R16), STO 55 will result in the NONEXISTENT display.
Clearing Storage Registers
Even though you have recalled or viewed the contents of a storage register, the number or string also remains in the storage register. You can clear storage registers in three ways:
  1. To clear the contents of a single storage register, merely store another number there. The original number is cleared by the new number.
  2. To clear a storage register, replace the number in it with zero. For example, to clear register R12, press 0 STO 12.
  3. To clear all storage registers at once, execute the CLRG (clear all registers) function. CLRG clears all currently allocated data storage registers to zeros. CLRG does not alter program memory or the automatic memory stack. CLRG must be assigned to a key for execution or executed from the display.