Manual / Guide · 2014
A 52-page English translation of the MK-61 operating manual (draft 1.0, October 2014), with the translator's notes on the stack, the power supply and DC-DC converter pins, the D2-10M adapter, test procedures, command codes and example programs.
MI CR O CA LC UL AT OR “ ELEKTRONIKA MK 61 ” FOR SCIENTIFIC, ENGINEERING AND STATISTICS CALCULATIONS OPERATING INSTRUCTIONS Elektronika MK-61 Calculator Operating Instructions Table of Contents Foreword .................................................................................................................................. 3 1. Notice to Owners .............................................................................................................. 4 2. Package Contents .............................................................................................................. 5 3. Safety Instructions ............................................................................................................ 6 4. Micro Calculator Specifications.......................................................................................... 7 5. Keyboard and Switches Description ................................................................................... 8 Latin keyboard layout transcription ....................................................................................... 8 Original Cyrillic keyboard layout ............................................................................................ 9 5.1. Primary functions on the key caps ............................................................................... 10 5.2. Additional symbols for shifted keys ............................................................................. 12 5.3. Additional register indirect commands ........................................................................ 14 6. Entering Data and Displaying Results ............................................................................... 15 7. Modes of Operation and Features ................................................................................... 16 “RUN” Mode ....................................................................................................................... 16 The Register Stack ............................................................................................................... 17 BCD system and Boolean Operations................................................................................... 19 “Programming” Mode ......................................................................................................... 21 Debugging ........................................................................................................................... 22 Indirect addressing revisited ............................................................................................... 23 Loop control........................................................................................................................ 23 8. Calculation functions accuracy ........................................................................................ 24 9. Technical data ................................................................................................................. 25 Average computation times ................................................................................................ 25 Power Supply ...................................................................................................................... 26 Environment considerations................................................................................................ 26 10. Invalid Operations and Overflow ................................................................................. 27 11. Battery Replacement ................................................................................................... 28 12. Storage and Handling .................................................................................................. 30 13. Warranty ..................................................................................................................... 31 14. Literature References .................................................................................................. 32 1 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 15. Appendix 1 - Test checklist .......................................................................................... 34 16. Appendix 2 - Command Codes ..................................................................................... 35 17. Appendix 3 - Program Examples .................................................................................. 36 Calculating the area of a circle............................................................................................. 36 Using unconditional indirect branching GTO (i) (K, БП) ........................................................ 37 Using conditional indirect branching x<0 (i) (K, x<0) ............................................................ 38 Looping calculations using commands such as DSNZ0 (F, L0) ............................................... 40 Looping calculations using indirect load RCL (i) (K, П→Х)..................................................... 42 18. Appendix 4 - Warranty Card ........................................................................................ 43 19. Appendix 5 - Tear-off Vouchers ................................................................................... 45 2 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions Foreword This book is an English translation of the original Russian Elektronika MK-61 Operating Instructions guide, circa 1996. There are other original versions of the Russian Elektronika MK-61 Operating Instructions guide, showing different organization and contents. This version was chosen because it was the most recent version found. The translation process was initiated by scanning the original paperback guide at 300dpi grey scale, and later converted to Cyrillic text using the ABBY Fine Reader tool. From that point forward, the translation was a manual time consuming process, using Google Translator as the main tool, and occasional assistance from Russian and Ukraine acquaintances. Enough care has been taken to be faithful to the original Russian text where possible. This means that some expressions have retained the Russian tone. For example, a calculator is designated as micro calculator and sometimes it is referred by its nick name as MK. Whenever possible, the original Cyrillic keyboard symbols are retained thru this book. They are written between parentheses just after the equivalent Latin symbols. Concerning the decimal separator symbol, despite the comma being used as decimal separator in the original Russian guide, the MK calculator uses the dot symbol printed on the decimal separator key. So in this guide the dot symbol was chosen in order to be consistent with the MK keyboard. Interestingly, the RPN term never appears in the original text, despite this MK-61 being a machine that operates as such. Footnotes were added stating that this is indeed a RPN calculator, though. To complement the original guide’s information, additional detail was included, based on Internet literature searches and testing on the physical MK-61 calculator. These remarks are presented as footnotes references. Many thanks to all contributors to this small project, namely the good people from the MoHPC, and special thanks to Sergei Frolov for giving permission to include parts of his work in this book. 3 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 1. Notice to Owners 1.1. When you purchase a micro calculator (MK) please check for all of its delivery contents, namely the MK quality control test, the presence of the warranty card in this manual, the two tear-off maintenance vouchers in compliance with the MK serial number and warranty card, the integrity of the seals on the device, and one power supply unit (PSU). 1.2. Make sure you have a warranty and a detachable coupon signature (stamp) of the seller, date of sale and shop stamp. 1.3. If the MK needs a repair during the warranty period, use the MK maintenance vouchers and register the number and date of issue. 1.4. Vouchers for repair are taken by the representative maintenance organization only after the remedial work intervention. 1.5. Before using the MK, please read this instruction manual. 1.6. If MK was transported in winter conditions or stored in a cold room, please keep it for 4 hours at room temperature before turning it on. 1.7. A self-adhering protective film is attached to the MK display color filter, but it can be removed if necessary. 1.8. After turning off the MK, allow a minimum of 30 seconds before switching it on again. 1.9. For a more detailed acquaintance with the construction and operation of the MK, use the reference literature listed at the end of the manual. 1.10. The factory is constantly improving the MK, so the product specification may change and it will not be reported in the manual, without prejudice to the buyer. 4 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 2. Package Contents 2.1. Micro Calculator "Elektronika MK 61” 2.2. Instruction Manual 2.3. Power Supply D2-10M 2.4. Packaging bundle with cardboard inserts, plastic bag, and pouch products. 5 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 3. Safety Instructions 3.1. The power supply calculator can only be opened and repaired by qualified personnel for such procedures. 3.2. Plugging the power supply to the 220VAC power grid without a calculator connected to the adapter is prohibited1. 3.3. The use of rechargeable batteries is prohibited. 1 See Chapters 9 and 11 for details . 6 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 4. Micro Calculator Specifications 4.1. Program memory of 105 steps. 4.2. Featured functions: - Arithmetic (+, ─, ˟, ÷ ); - Direct and inverse trigonometric ( sin, cos, tg, sin-1, cos-1, tg-1 ); - Logarithmic ( lg, ln ); - Calculations ( xy, ex, √x, x2, 1/x ) - Constants ( π ) - Isolation of the decimal (fractional) part of a number, determination of their absolute magnitude and sign, maximum value between two numbers, inverse of a number; - Pseudo-random numbers generation between 0 and 1; - Convert angular (time) values, expressed in degrees (hours), minutes, and fractions of a minute, in values expressed in degrees (hours) and fractions of degrees (hour), and vice-versa; - Logical bitwise operations for addition, multiplication, xor, and negation. 4.3. Store data in the 15 memory registers RG0-RG9, RGa-RGe and recall them to read stored data into the stack registers; Stack registers X, Y, Z, T data rotation; exchange of data between the registers X and Y; clearing the X register and retrieve the previous value of register X after an operation execution, thru the register X1. 4.4. Perform operations requiring a single value in register X (ln, sin, among others), double values operations with numbers in registers X and Y (arithmetic, etc.), and chain operations. 4.5. Creating, editing and correction programs, commands for direct and indirect jumps, call to subroutines with handling of up to 5 levels of depth, commands for direct and indirect unconditional jumps, conditional jumps, looping commands, indirect entries in registers, indirect branching on the contents of registers, program counter reset command, start and stop execution in the Run mode, commands to step through a program, display up to three program code steps per line with indication of the current address of the program counter. 7 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 5. Keyboard and Switches Description Latin keyboard layout transcription 8 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions Original Cyrillic keyboard layout 9 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 5.1. Primary functions on the key caps The exterior view of the original Russian MK-61 is shown in Fig.1 below. to , - Numeric keys for data entry into the register X, using digits 0 through 9, plus the decimal point. , , , - Keys to do arithmetic operations 2 (addition, subtraction, multiplication and division). LED Display Power Angle Switch Switch "ON / "Radians / / OFF" Grads / Degrees" Keyboard Fig.1. Exterior view of the micro calculator (MK) 2 This is a RPN calculator, therefore it uses postfix notation where the parentheses and the equal keys are not needed. To do a math operation, first enter the operand(s), then chose the operator. 10 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions , , , , - From left to right: The ENTER (В↑) key is used for data entry into stack register X; The EEX (ВП) key is used to input the exponent of a number; The CHS (/─/) key change the sign of mantissa or exponent; The x↔y (↔) key exchange data contents between the registers of X and Y; The CX key clears the contents of register X. , - The SST (ШГ→) and BST (ШГ←) keys are used to single-step through a program. , - The STO (Х→П) key stores the X register content in one of the addressable memory registers. The RCL (П→Х) key loads the register X with one of the addressable memory register’s contents3. , - In "PROGRAM” mode, the GTO (БП) key specifies an unconditional jump, while the GSB (ПП) key indicates a call to a subroutine. In "RUN" mode these keys step through a program. - In "PROGRAM" mode, the RTN/0 (В/0) key returns from a subroutine, while it goes to address zero when in the "RUN" mode. - In “PROGRAM” mode, the R/S (С/П) key is used to stop a program execution and display the register X contents. In “RUN” mode, it starts or stop a program or a loop cycle. , - The F and K keys select the shift functions, whose symbols are printed above the other MK’s keys in yellow (F) or blue (K) color. 3 The MK-61 has got 15 addressable memory registers (RG0 to RG9, and “RGa” to “RGe) for additional data storage and to support a number programming features like looping control and indirect branching. The calculator operations uses a primary memory area: The stack with 4 registers (X, Y, Z, T), plus one additional register X1 used to automatically save the previous register X value when executing a command that modifies the register X contents. 11 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 5.2. Additional symbols for shifted keys , - The F, CF combination cancels the shift key selection. , - The F, LST x (F, Вх) combination retrieve the previous value of X after an operation execution. , ; , - The F, RUN (F, АВТ) combination selects the “RUN” mode, while F, PRG (А, ПРГ) enters into the "PROGRAM” mode. , ; , ; , ; , These four key combinations x<0, x=0, x≥0, x≠0 gives direct access to the four corresponding logic conditions. , ; , ; , ; , These four key combinations F, DSNZ0 (F, L0), F, DSNZ1 (F, L1), F, DSNZ2 (F, L2), F, DSNZ3 (F, L3) allows loop control by using conditional direct branch depending on the contents of register 0, 1, 2 or 3, respectively. , - The F, R↓ combination rotates data thru the 4-stack registers. , ; , ; , ; , ; , - From left to right, these five key combinations allow to determine: The integer part: K, INT (K, [x]) The fractional part of a number: K, FRAC (K, {x}) The absolute magnitude: K, |x| The sign: K, sign (K,ЗН) Find the maximum of two numbers: K, max 12 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions , ; , - From left to right: The combination K, HH.M.S converts from sexagesimal degrees (hours), minutes, seconds and fractions of seconds, into decimal angular (time) values. The combination K, HH.M.S converts from decimal angular (time) values into sexagesimal degrees (hours), minutes, seconds and fractions of seconds. , ; , - From left to right: The combination HH.M converts from sexagesimal degrees (hours), minutes, and fractions of a minute, into decimal angular (time) values. The combination HH.M converts between decimal angular (time) values into sexagesimal degrees (hours), minutes, and fractions of a minute. , ; , ; , ; , These four key combinations are used for bitwise logical operations. From left to right: Multiplication: K, AND Addition: K, OR Exclusive or: K, XOR Negation (one’s complement): K, NOT (K, ИНВ) , - This key combination K, RND (K, СЧ) generates pseudo random numbers. , - This key combination K, NOP (K, НОП) invokes a "No Operation". 13 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 5.3. Additional register indirect commands , - This key combination K + GTO(i) (K, БП) does an unconditional indirect branch by jumping to an address stored in of one of the registers RG0 to RG9 and RGa to RGe. , - This key combination K, X<0 (i) does a conditional indirect jump to the address stored in one of the registers RG0 to RG9 and RGa to RGe. Similar operations are carried out under the conditions for indirect branching for the remaining three commands: , ; , ; , , - This key combination K, GSB(i) (K, ПП) does an indirect call to a subroutine according to the address stored in one of the registers RG0 to RG9 and RGa to RGe. , - This key combination K, RCL(i) (K, П→Х) 4 does an indirect load of register X with the contents of one of the 15 registers whose number is specified in one of the registers RG0 to RG9 and RGa to RGe. , - And of course the indirect store operation is available as well. This key combination K, STO(i) (K, Х→П) takes the value of register X and does an indirect store into one memory register referenced by one of the registers RG0 to RG9 and RGa to RGe. 4 Suppose RG7 contents = 123; we want to load stack Reg. X with the RG7 contents by using indirect addressing, and we chose RG0 as the pointer. What is the value to assign to RG0? In this case, store the value 8 into the RG0 in order to retrieve the RG7 contents at the first try. Why? Because when the instruction executes, first RG0 is modified and decremented by one, before looking into its indirect pointer value. This “decrement by one” behavior is only valid for register pointers RG0 to RG3, and applies to all instructions using them. However, this “decrement by one” sometimes takes place before the lookup, for example for instructions like the RCL(i). And for other instructions, like GTO(i), it happens after the lookup. As for the registers RG4 to RG6, they are first incremented by one before the lookup operation. However, registers RG7-RG9 and RGa-RGe are modified but the value is not changed during execution. Registers RG0-RG9, RGa-RGe correspond to modified codes from 0000000 to 0000014 (using leading 0’s) 14 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 6. Entering Data and Displaying Results 6.1. MK numeric system - Decimal. The information is displayed on the 12 digits luminous discharge type display, sporting a green glow; it has 8-digits for mantissa, 2-digits for exponent, 1-digit for mantissa sign and another digit for exponent sign. 6.2. The MK calculation range is: 1˟10-99 ≤ x ≤ 9.9999999˟1099 The results of calculations in the range of 1 ≤ x ≤ 99999999 are displayed in the natural form, and outside this range are displayed as floating-point numbers. 6.3. The data is introduced in the MK by pressing the appropriate keys. To introduce fractional numbers, first type the integer part, then the decimal point, and then the fractional part. 6.4. When you enter a number with exponent, the mantissas is introduced first and then press the key EEX (ВП) to enter the exponent value. To change mantissa or exponent signs, press the key /─/ after typing the values. 6.5. Pressing the key ENTER (В↑) normalizes the inputted number in stack Reg. X, and a copy of the register X will go into register Y as well5. 6.6. After you enter an eight-digit mantissa number, further pressing additional number keys does not change the display reading. 5 The 4-register stack lift operation is automatic on the ENTER key execution: The Reg. Y content is also copied to Reg. T, and the previous Reg. T contents is lost. 15 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 7. Modes of Operation and Features 7.1. The MK works in one of two modes: "RUN" or “PROGRAMMING". “RUN” Mode 7.2. The "Run" mode is set immediately after switching ON the MK, or after clicking the key combination , F, RUN (F, АВТ) 7.3. When performing single number operations, first type the numeric argument on the keyboard, then press the key F and then press the corresponding function. 7.4. Before performing the direct or inverse trigonometric functions, set the switch RAD / GRD / DEG ( Р / ГРД / Г ) to the desired angles units. 7.5. When converting time (angle) values, the hours (degrees) value is separated from the value for minutes, seconds and fractions of second by the decimal point. For example, the following time value: 142.24314 – Represents 142 hours, 24 minutes, and 31.4 seconds6. 7.6. To call a pseudo-random number to be displayed, type in a seed number and press the keys , , ENTER, K, RND. When the MK memory is reset, the generated number will be equal to 0.404067. 7.7. When performing double number operations, start by typing the first number on the keypad, next introduce it with the key ENTER, then type the second number, and press the button for the desired function. The display will show the result of the operation. 6 To get this time result, type the decimal value 142.40874 and then choose , H→H.M.S 16 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions The Register Stack 7.8. The MK has got a memory stack with the registers X, Y, Z, T. After switching on the MK, there is no data in these registers. Entering information into the stack always occurs through the register X. Pressing the key ENTER will copy the number in register X into register Y, and Y into Z, and Z into T. In this way, the content of the register X is preserved 7. 7.9. Pressing the key combination , F, R↓, data rotates through the stack: X→T→Z→Y→X 7.10. When performing single number operations, the MK operates with a number from register X, and the contents of registers Y, Z, T are not modified. The operation result is stored back in register X, but a copy of its previous content is copied into the register X1 – This register X1 saves the previous register X content from being lost as a result of another operation execution. In this way, the result of one single number operation remains in register X and its value is shown in the MK display. 7.11. To check the content register X1 press key the combination , F, LST x (F, Вх). It is cleared (or cancel any other operation command) by using the key CX. 7 RPN calculators are not created equal. Each different RPN machine vendor and model behaves in its specific and unique way. RPN was adopted by HP since the beginning of the slide rule obsolescence with their HP-35 calculator invention. And since then, HP calculators did evolve with the passing time, and there are at least three different behaviors handling the stack operations, depending on calculator models. What about the MK-61 RPN register stack operations behavior? Well, running the stack lift test (5, ENTER, CHS, 2, +) mentioned in the HP Solve #27 “HP RPN Evolves” article by Richard J. Nelson, the result is 7. This places the MK-61 in the same league as the HP Classics, like the famous HP-25 or HP-65 machines. 17 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 7.12. The four stack registers and the previous X value in register X1 facilitate complex calculations8. 7.13. To store the register X contents into one of the additional 15 memory registers, use the key STO (Х→П) and choose the destination register number with one of the keys to and to . To load register X with a number from a memory register contents, press key RCL (П→Х) followed by one of the source register numbers. 7.14. To clear a memory register by writing zero into it, use the key CX followed by the key STO (Х→П) and choose the destination register address number. To clear all MK memory registers, simply turn off the calculator9. 8 MK-61 RPN stack manipulation details are beyond the scope here, but let’s see a couple of examples. The stack Register X is linked to the Display, so its content is always visible. When typing a number, it is being entered into Register X. There is no need to do an ENTER to execute single number operations. On the above example, when executing Sin(45), it first copies reg. X contents into Reg. X1, then calculates the Sin(45) function, and the result is put back into Reg. X. If we retrieve the previous Reg. X value, it will invoke an automatic stack lift up (X goes into Y, Y into Z, Z into T, and previous T content is lost), to free up Reg. X to receive the LST x operator result. On the next example, we pushed 3 numbers into the Y, Z, T stack registers, leaving X=Y. A Multiply consumes X and Y as operands, leaving the answer in X. During the execution, an automatic stack lift down was executed (T goes into Z, Z goes into Y) leaving T and Z with identical contents. 9 After switching off the calculator, please allow at least 30 seconds before turning it back on. See Chapter 1. Notice to Owners. 18 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions BCD system and Boolean Operations 7.15. Numbers in the MK are implemented in a BCD system, so Boolean operations can be used on them. The binary values for each number and respective display character are shown in Table 1. Information in registers Symbol on the In the decimal In the BCD display system system 0 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0110 7 0111 8 1000 9 1001 10 1010 11 1011 12 1100 13 1101 14 1110 15 1111 (blank) Table 1 – BCD system symbol display 19 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 7.16. The output from bitwise logical operations execution is signaled by the presence of the digit “8” on the leftmost part of the displayed number. When you enter values in register X and Y for Boolean operations, it is also necessary to type in a digit other than 0 in the most significant digit of the inputted numbers. 7.17. Example for a bitwise logical addition: 8888888 OR 7770665 Keystrokes: , , , , , , , , , , , , , , , , , Please note an extra digit, in this case with the value 1, was typed in to fill the leftmost position of each number to be evaluated by a Boolean operator. The result on the vacuum fluorescent display will show a value of10: Note the digit 8 in the leftmost position of the result – This is the sign of a Boolean logical operation. 10 These are two numbers having 7-digit with 4-bit each, to be added with the Boolean bitwise OR operator. As for the result, we get 7-digits with 4-bit each with the following values: 15, 15, 15, 8, 14, 14, 13 According to the “Table 1 – BCD system symbol display”, we expect to see these symbols on display: - Three blank characters; - An “8” - Two “E”’s - A “Г” 20 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions “Programming” Mode 7.18. To go into "PROGRAM" mode, press , F, PROG (F, ПРГ). In this mode, the codes for numbers, operations and commands11 are written into the MK 105 memory cells, from addresses 00 to 104 12. 7.19. The MK has an internal Program Counter (PC) that changes its content with the specified jump addresses or recorded in the registers RG0-RG9, RGa-RGe. 7.20. The MK shows the current address of the PC at the rightmost position of the display13. 7.21. To create complex programs with subroutines, there are commands for direct and indirect branching, indirect subroutine calls and data storing, and loop controls. When typing these commands in the program one should specify the branch address (except for indirect branching commands, which already contains the address). 11 See Appendix 2 - Command Codes 12 In reality step 00 is not available to store any instructions. The first memory address available to store a command is 01. See the MK-61 behavior below for details. 13 Up to three of the previously entered commands are displayed on the next positions from right (at a lower PC address) to left (at a higher PC address). The command at the current PC address is located at the leftmost position of the display. Each command takes 2 digits on the display. Example to code 1/π2 (a complete program needs to be terminated by a R/S command, though). Keystrokes Result on the display 21 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions 7.22. Addresses branching from 00 to 99 are typed by pressing the corresponding number keys. Addresses branching from 100 to 104 are used only for direct branching commands and are typed using the key and one of the keys from to . The addresses from 00 to 99 are displayed using the appropriate numbers, but for the addresses from 100 to 104 the two digits used at hundreds and tens positions are displayed with a “minus" sign. For example, the address 102 is displayed as -2. 7.23. To begin a program at address zero, select the "RUN” mode and reset the Program Counter to zero by pressing RTN/0 (В/0), and then switch to "PROGRAM” mode. The display will show the address 00. 7.24. If you want to start a program at any specific address, select the "RUN" mode and press the key GTO (БП) followed by the required address, and then turn into the "PROGRAM" mode. Debugging 7.25. Debugging programs is done in "RUN" mode by pressing key SST (ШГ→). Typically the required raw data needs to be entered in the appropriate registers, and then set the start address of the program. Finally execute the program in single step mode by using the key SST (ШГ→). Alternatively run the program in automatic mode by using the key R/S (С/П). In the latter case, the display blinks during the program execution. WARNING! When you turn off the MK, programs and data are lost. 22 Draft version 1.0 – Oct.2014 Please send corrections to Jose Mesquita ([email protected]) Elektronika MK-61 Calculator Operating Instructions Indirect addressing revisited 7.26. When executing commands for indirect unconditional jump GTO (i) followed by the address register), modification occurs in the contents of the address register after the execution of the command, pointing to a new address. If the command uses the address registers: 14 RG0-RG3 - their content is decremented by 1; RG4-RG5 - their content is increased by 1; RG7-RG9 and RGa-RGe – Their content does not change. 7.27. When using the indirect store STO(i) (K, Х→П), modification also occurs on the contents of addressable register, and writes the contents of register X into the address that is pointed to by the modified code. Registers RG0-RG9, RGa-RGe correspond to modified codes 15 from 0000000 to 0000014. 7.28. When using the indirect load command RCL(i) (K, П→Х), modification occurs on the contents of addressable register, and loads register X with the contents of the address that is pointed to by the modified code. Loop control 7.29. Computing cycles can be implemented by using the commands DSNZ0 to DSNZ03, as referenced in the register RG0 to RG3, respectively. For each loop, the content of the address register is subtracted by 1 and test if its content is equals to 0. If address register equals 0 then execution continues after the next instruction, otherwise execution jumps to the specifi