MK-61 Command Reference

Key	Commands
	Power off/on
	R Use radians (2p) for trigonometric functions GRA Use grad (400) G Use degrees (360)
	normal n/a SST: In programming mode display next program step. Strange things happen when stepping forward beyond the end of the program. shift-F 5C XX JP X<0: Programming instruction: If X<0 then continue normally, otherwise jump to 2-digit program address that follows shift-K C0-CF (C0-C_) JPI x<0: Programming instruction: If X<0 then continue normally, otherwise jump to 2-digit program address that is stored in the specified register. If register number is 0-3 then the register is decremented as well.
	normal n/a BST: In programming mode display previous program step. Strange things happen when stepping backwards beyond. shift-F 5E XX JP X=0: Programming instruction: If X=0 then continue normally, otherwise jump to 2-digit program address that follows shift-K E0-EF (E0-E_) JPI X=0: Programming instruction: If X=0 then continue normally, otherwise jump to 2-digit program address that is stored in the specified register. If register number is 0-3 then the register is decremented as well.
	normal 52 RTN: In calculator mode: Set program counter to 00. In program mode: Returns from subroutine or goes to address 0 if no subroutine call is pending. shift-F 59 XX JP X>=0: Programming instruction: If X>=0 then continue normally, otherwise jump to 2-digit program address that follows shift-K 90-9F (90-9_) JPI X>=0: Programming instruction: If X>=0 then continue normally, otherwise jump to 2-digit program address that is stored in the specified register. If register number is 0-3 then the register is decremented as well.
	normal 50 R/S: In calculator mode: Continue program from current address or stop running program. In program mode: Halt program. shift-F 57 XX JP X<>0: Programming instruction: If X<>0 then continue normally, otherwise jump to 2-digit program address that follows shift-K 70-7F (70-7_) JPI X<>0: Programming instruction: If X<>0 then continue normally, otherwise jump to 2-digit program address that is stored in the specified register. If register number is 0-3 then the register is decremented as well.
	normal 40 - 4F  (40-4_) RCL: Recall register 0-9 or a-e and push into X. The letters "a"-"e" are printed below 5 keys at the lower end of the keyboard. shift-F 5D (5G) DSNZ0: Programming instruction: If register 0 is >=2 then it is decremented and execution jumps to the address that follows. If register 0 is <2 then it is not decremented and execution continues normally. shift-K D0-DF (G0-G_) RCLI: Indirect recall using the register number that follows. If register number is 0-3 then the register is decremented after the recall.
	normal 60 - 6F  (60-6_) STO: Store X in variable register 0-9 or a-e. The letters "a"-"e" are printed below 5 keys at the lower end of the keyboard. shift-F 5B DSNZ1: Programming instruction: If register 1 is >=2 then it is decremented and execution jumps to the address that follows. If register 1 is <2 then it is not decremented and execution continues normally. shift-K B0-BF (L0-L_) STOI: Indirect store using the register number that follows. If register number is 0-3 then the register is decremented after the store.
	normal 51 XX JP: Programming or calculator mode: Jump to address that follows. shift-F 58 DSNZ2: Programming instruction: If register 2 is >=2 then it is decremented and execution jumps to the address that follows. If register 2 is <2 then it is not decremented and execution continues normally. shift-K 80-8F (80-8_) JPI: Indirect jump using the register number that follows. If register number is 0-3 then the register is decremented after the jump.
	normal 53 XX GSB/SST: In calculator mode: Peform one program step. In programming mode: Perform subroutine call to address that follows. Use the "B/O" command to return from a subroutine. shift-F 5A (5-) DSNZ3: Programming instruction: If register 3 is >=2 then it is decremented and execution jumps to the address that follows. If register 3 is <2 then it is not decremented and execution continues normally. shift-K A0-AF (-0 - -_) GSBI: Indirect subroutine call using the register number that follows. If register number is 0-3 then the register is decremented after the call.
	normal 07 Number 7 shift-F 1C Sine of X shift-K 34 INT: Integer part of X
	normal 08 Number 8 shift-F 1D (1G) Cosine of X shift-K 35 FRAC: Fractional part of X
	normal 09 Number 9 shift-F 1E Tangent of X shift-K 36 Replaces X with the higher value of X and Y. Does not drop the stack. Warning: If X or Y is 0 then the result is always 0! Maybe a bug.
	normal 11 Substract Y-X shift-F 21 Square root of X shift-K 27 Undefined function. Causes ERROR
	normal 13 Divide Y/X. Note that when dividing by 0 the display will go blank for about 5 (!) seconds before the error condition is displayed. shift-F 23 Reziprocal of X shift-K 29 Undefined function. Causes ERROR
	normal 04 Number 4 shift-F 19 Inverse sine of X shift-K 31 ABS: Absolute value of X
	normal 05 Number 5 shift-F 1A (1-) Inverse cosine of X shift-K 32 SIGN: Signum of X: -1 if X<0, 0 if X=0, 1 if X>0
	normal 06 Number 6 shift-F 1E Inverse tangent of X shift-K 33 H-HM: Convert decimal hours to hours.minutes
	normal 10 Add Y+X shift-F 20 Number pi=3.1415... shift-K 26 HM-H: Convert hours.minutes to decimal hours Example: 2.3030 -> 2.505
	normal 12 Multiply Y*X shift-F 22 Sqare of X shift-K 28 Undefined function. Causes ERROR
	normal 01 Number 1 shift-F 16 Exponential of X shift-K 55 No function
	normal 02 Number 2 shift-F 17 Logarithm base 10 of X shift-K 56 No function
	normal 03 Number 3 shift-F 18 Natural logarithm of X shift-K 30 H-HMS: Convert decimal hours to hours.minutes/seconds
	normal 14 Swap X and Y stack register shift-F 24 X to the power of Y. This is reversed comapred to the "normal" mode! shift-K 2A (2-) HMS-H: Convert hours.minutes/seconds to decimal hours Example: 2.3030 -> 2.508333
	normal 0E Push stack (ENTER) shift-F 0F (0_) Last-X register shift-K 3B (3L) RND: Create a random number 0<=X<1
	normal 00 Number 0 shift-F 15 10 to the power of X shift-K 54 Programming instruction: NOP (no operation)
	normal 0A (0-) Decimal point. Note that a digit must be entered before the decimal point! Also, the programming instruction "EXP ." seems to do surprising things. shift-F 25 Rotate stack down. shift-K 37 Perform binary operation Y AND X
	normal 0B (0L) Change sign of X shift-F n/a Normal calculator mode (switches out of programming mode). shift-K 38 Perform binary operation Y OR X
	normal 0C Enter exponent shift-F n/a Activate programming mode. shift-K 39 Perform binary operation Y XOR X
	normal 0D (0G) Clear X-register shift-F n/a Apparently clears the prefix key. Note that the prefix keys override each other. So in order to clear the K prefix key press F and then CF. shift-K 3A (3-) Perform binary operation NOT X

Binary Operations

Programming

• Program entry starts at step 00.
  
 
• The rightmost two digits in the display indicate the current program step.
Any commands entered will replace this program step.
On the left-hand side of the display there are at most three keycodes displayed. These are the codes of previous program steps! The leftmost code is the step just preceeding the one indicated in the program counter. Example:

Display	Program steps and codes
40 00 01 03	00: 01 = 1 01: 00 = 0 02: 40 = STO 0 03: Current program counter

This is a little bit confusing. Alternatively, you can think of the left-most keycode representing the program step indicated to the right - but then you have to modify jump addresses accordingly!
 
• Program addresses are displayed in decimal.
Program keycodes are displayed as hexadecimal numbers. See Binary Operations for binary number display.
The keycodes are listed in the above table.

• There are 105 program steps, 0-104 ("00" - "99" and after this "-0" - "-4").
To specify steps 100-104 use ".0" to ".4".
Program steps after 104 are identical to steps 0 and subsequent ones (ie. step 105 is identical to step 0).