The HP-41C Alphanumeric Programmable
Scientific Calculator
Primary Data Storage Registers
The standard HP-41C has 63 registers that can be allocated to data storage or program memory in any combination. As you add HP memory Modules (up to four), the total number of registers can increase to 319-64 registers for each memory module. When allocated, data storage registers numbered R00 through R99 are Primary Data Storage Registers.
  R00  
 
 
  R01  
 
 
  R02  
 
 
   
    •
  •
  • 		 
 
  R99  
 
 
Extended Data Storage Registers
When allocated, data storage registers numbered R(100) through R(319) are extended Data Storage Registers.
  R(100)  
 
 
  R(101)  
 
 
  R(102)  
 
 
   
    •
  •
  • 		 
 
  R(318)  
 
 
Program Memory
All registers that are not allocated as Primary or Extended data storage registers are part of program memory. When allocated as program memory, the standard HP-41C registers provide space for 200-400 fully-merged lines of programs. When allocated as program memory, each memory module adds 200-400 lines. The total can be 1000-2000 lines when all 319 registers are allocated as program memory. Variations in storage capacity depend on the kinds of functions stored in program memory.
Port locations
 
1 2
3 4
 
The Automatic Memory Stack
  Registers
  T   
 
 
  Z   
 
 
  Y   
 
 
  X   
 
 
  LAST X   
 
 
The ALPHA Register
(Holds up to 24 characters)
 
 
 
*** HP-41C ***
ALPHA  
    ON     USER   PRGM   ALPHA  
  Σ-   yx   x2   10x   ex  
  Σ+   1/x       LOG   LN  
  A   B   C   D   E  
  CLΣ   %   SIN-1   COS-1   TAN-1  
  X‹›Y   R     SIN   COS   TAN  
  F   G   H   I   J  
      ASN   LBL   GTO   BST  
      XEQ   STO   RCL   SST  
      K   L   M      
  CATALOG   ISG   RTN   CLX/A
  ENTER     CHS   EEX       
  N   O   P      
  X=Y?   SF   CF   FS?  
  —   7   8   9  
  Q   R   S   T  
  X≤Y?   BEEP   P→R   R→P  
  +   4   5   6  
  U   V   W   X  
  X>Y?   FIX   SCI   ENG  
  ×   1   2   3  
  Y   Z   =   ?  
  X=0?   π LASTX VIEW  
  ÷   0   ·   R/S  
  :   SPACE   ,      
CAUTION
Always turn the HP-41C off before inserting or removing any plug-in extensions or accessories. Failure to do so could damage both calculator and the accessory.