DM42 Functions

Source:
* HP-42s Owner's Manual
* Docs on Free42 by Thomas Okken
--- Version 2.0.2, 2025-04-22 ---

A B C D E F G H I J K L M
N O P Q R S T U V W X Y
Z-etc

Use following link to open the DM42 Quick Reference Guide help file.

------- A -------

ABS
Absolute value
ACOS
Arc cosine
ACOSH
Arc hyperbolic cosine
ADATE
Appends the contents of the X register to the ALPHA register, formatted as a date value.
ADV
Advance paper one line
AGRAPH
Alpha graphics. Displays a graphics image. Each character in the Alpha register specifies an 8-dot column pattern. The X- and Y-registers specify the pixel location of the image.
AIP
Appends integer part of x to the Alpha register.
ALENG
Alpha length
ALL
Select the All display format
ALLΣ
ALLΣ mode (13 sum regs)
AND
Logical AND
ANUM
Scans the ALPHA register for a number, and places it into the X register. If a number is found, the numeric input flag, flag 22, is set.
AOFF
Alpha off. Exits from the ALPHA menu.
AON
Alpha on. Selects the ALPHA menu.
APPEND
Adds the object in X to the string or list in Y and returns the combined string or list. If Y is a string, the contents of X will be converted to a string in the same way as ARCL. If Y is a list, X will be added to it unchanged. If X is a list, it will be added to Y as one element.
ARCL
Alpha recall. Copies data into the Alpha register appending it to the current contents. Numbers are formatted using the current display format.
AROT
Alpha rotate. Rotates the Alpha register by the number of characters specified in the X-register.
ASHF
Alpha shift. Shifts the six left-most characters out of the Alpha register.
ASIN
Arc sine
ASINH
Arc hyperbolic sine
ASSIGN
Assign CUSTOM menu key
ASTO
Alpha store. Copies the first six characters in the Alpha register into a register or variable.
ATIME
Appends time content of the X register to the ALPHA register, formatted as a time value.
ATIME24
Like ATIME, except it always formats the time in 24-hour format, regardless of the CLK12/CLK24 setting
ATAN
Arc tangent
ATANH
Arc hyperbolic tangent
ATOX
Alpha to X. Converts the left-most character in the Alpha register to its character code (returned to the X-register) and deletes the character.
AVIEW
Alpha view. Displays the Alpha register.
A2LINE , A2+LINE , and X2LINE
Create program lines containing the current contents of the ALPHA register, to be set; the ALPHA register, to be appended; and X register, respectively.
A...F
Sets HEXM mode and activates the A...F menu.

------- B -------

BASE+
Base add; Returns the 36-bit sum of y + x.
BASE-
Base subtract
BASE×
Base multiply
BASE÷
Base divide
BASE+/-
Base change sign (Base change sign. Returns the 36-bit 2's complement of x.)
BEEP
Sounds a sequence of four tones.
BEST
Best ﬁt model
BINM
Selects Binary mode (base 2).
BIT?
Bit test (x-th bit of y)
BRESET
Resets all BASE modes back to their defaults, which match the behavior of the real HP-42S: WSIZE 36, signed, not wrapped.
BSIGNED
Toggles signed mode. In signed mode, numbers are interpreted as two's complement signed integers; in unsigned mode, numbers are always interpreted as non-negative, and negative numbers do not exist. You can check whether signed or unsigned mode is active by checking the MODES menu, where there will be a dot marking the BSGN menu item when signed mode is active. Alternatively, you can check flag 78.
BST
Back step
BWRAP
Toggles wrapped mode. In wrapped mode, numbers are kept within WSIZE bits by discarding any bits to the left of bit WSIZE - 1; in non-wrapped mode, numbers outside of the binary range are not allowed and cause Invalid Data errors when parameters are out of range, or Out of Range errors when results are out of range. You can check whether wrapped or non-wrapped mode is active by checking the MODES menu (dot marking the BWRP menu item when wrapped mode is active, alternatively, you can check flag 79).

------- C -------

CAPS and Mixed
Select whether to display menu labels in all caps, or allow lowercase letters. The HP-42S displays menu all menu labels in all caps, because its menu font doesn't have lowercase letters. Free42, however, has had lowercase letters in its menu font since release 3.0.6. The CAPS setting can be used to preserve the original HP-42S look; the Mixed setting is the new default.
C.LN1+X and C.E↑X-1
These are complex-capable versions of the HP-42S LN1+X and E↑X-1 functions.
CF
Clear ﬂag
CLA
Clear alpha register
CLALL
Clear all memory
CLD
Clear display. Clears a message from the display.
CLKEYS
Clear CUSTOM menu keys
CLK12
Display the time in 12-hour format with AM/PM
CLK24
Display the time in 24-hour format
CLLCD
Clear LCD
CLMENU
Clear programmable menu
CLP
Clear program
CLRG
Clear registers
CLST
Clear stack
CLV
Clear variable
CLX
Clear X-register
CLΣ
Clear summation registers
COMB
Combinations of y items taken x at a time. Returns y!/(x!(y — x)!) .
COMPLEX
Converts two real numbers (or matrices) into a complex number (or matrix). Converts a complex number (or matrix) into two real numbers (or matrices).
CORR
Returns a correlation coefficient using the current statistical data and curve-fitting model.
COS
Cosine
COSH
Hyperbolic cosine
CPXMAT?
Tests whether the object in the X register is a complex matrix.
CPXRES
Complex-result enable
CPX?
If the X-register contains a complex number, executes the next program line; if the X-register does not contain a complex number, skips the next program line.
CROSS
Cross product
CSLD?
"Caller's Stack Lift Disabled?" Tests whether the 'stack lift disable' flag (30) was set when the latest XEQ was performed. This can be used when writing functions that return values on the stack, so they exhibit RCL-like behavior when called after CLX or ENTER.
CUSTOM
CUSTOM menu
C→N and N→C
Convert character to number or number to character, like ATOX and XTOA.

------- D -------

DATE
Returns the current date to the X register
DATE+
Takes a date from the Y register, and adds a number of days from the X register.
DDAYS
Calculates the number of days between the date in the Y register and the date in the X register. If the date in the Y register is earlier, then the result will be positive.
DECM
Decimal mode
DEG
Degrees mode
DEL
Delete program lines. In Program-entry mode only: From current program pointer position deletes the specified number of lines (not programmable).
DELAY
Printer delay time
DELR
Delete matrix row. In Matrix-Editor: Deletes the current row.
DEPTH
[Big Stack] Returns the current stack depth.
DET
Determinant
DIM
Dimensions a matrix to x columns and y rows. If the matrix does not exist, DIM creates it.
DIM?
Dimensions of matrix in X
DMY
Display, return, and accept dates in day/month/year format
DOT
Returns the dot product of two vectors (matrices or complex numbers).
DOW
Calculates the day of the week for the date in the X register. Returns a number from 0 to 6, where 0 is Sunday, 1 is Monday, and so on. When this function is executed from the keyboard, the day is also displayed in a human-friendly format, i.e. MON for Monday, TUE for Tuesday, etc.
DROP and DROPN n
[Big Stack] Drops level 1, or levels 1..n. In 4-level mode, the stack is replenished with zeroes from the top.
DSE
Decrement, skip if (less than or) equal. Given ccccccc.fffii in a variable or register, decrements ccccccc by ii and skips the next program line if ccccccc is now ≤ fff.
DUP and DUPN n
[Big Stack] Duplicates level 1, or levels 1..n. In 4-level mode, n must be 2 or less.

------- E -------

EDIT
Edit matrix in X-register
EDITN
Edit named matrix
END
End of a program
ENG
Engineering display format
ENTER
Separates two numbers keyed in sequentially.
ERRMSG and ERRNO
These functions return the error message and error number, respectively, for the most recent error to be caught using flag 25. If the error number is outside of the range 1 through 8, the same range that is accepted by RTNERR, then ERRNO will return the error message instead, identical to what is returned by ERRMSG.
EXITALL
Exit all menus
EXPF
Curve-fitting model: exp.
EXTEND
Adds the object in X to the string or list in Y and returns the combined string or list. If Y is a string, the contents of X will be converted to a string in the same way as ARCL. If Y is a list, X will be added to it unchanged. If X is a list, it will be added to Y element by element.
E↑X
Natural exponential
E↑X-1
Natural exponential for values of x which are close to zero. Returns E↑X-1, which provides a much higher accuracy in the fractional part of the result.

------- F -------

FC?
If the specified flag is clear, executes the next program line; if the flag is set, skips the next program line.
FC?C
If the specified flag is clear, executes the next program line; if the flag is set, skips the next program line. Cleared after the test is complete. (This function can be used only with flags 00 through 35 and 81 through 99.)
FCSTX
Forecast x given y (stat)
FCSTY
Forecast y given x (stat)
[FIND]
locates a specific value, searching the indexed matrix left to right and top to bottom. The function works as a conditional: when a program is running, the following instruction is executed if a match is found, and skipped if a match is not found; when executed interactively, the display shows "Yes" if a match is found and "No" if not. Also, if a match is found, I and J are set to point to it.
The indexed matrix may be real or complex, and the search value may be real, complex, or string; real or string values are only found in real matrices, and complex values are only found in complex matrices; in other words, 5 is not considered equal to 5 + 0i -- mathematically speaking this is wrong, but on the other hand it is consistent with the behavior of the X=Y? and X≠Y? functions.
FIX
Fixed dec. display format
FMA
Fused Multiply-Add. Calculates Z*Y+X using the underlying platform's native FMA function, as provided by the floating-point hardware or library.
FP
Return fractional part
FRNM
Frobenius norm of X matrix
FS?
If the specified flag is set, executes the next program line; if the flag is clear, skips the next program line.
FS?C
If the specified flag is set, executes the next program line; if the flag is clear, skips the next program line. Clears the flag after the test is complete. (This function can be used only with flags 00 through 35 and 81 through 99.)
FUNC
Prepare user-defined function. Save the contents of the stack and LASTx; when the function returns, this saved data will be used to restore the stack such that it looks as if a built-in function has executed. FUNC takes a two-digit numeric parameter. Each digit can be from 0 to 4. The first digit indicates the number of parameters consumed by the user-defined function, and the second digit indicates the number of values returned.

------- G -------

GAMMA
Gamma function
GETKEY
Put next key number to X-reg. The calculator waits for you to press a key. When you do, the key number is returned to the X-register.
GETKEY1
This function works like the regular GETKEY, except it does not halt program execution when EXIT or Shift-EXIT are pressed, allowing programs to implement custom behaviors for those keys. GETKEY1 does halt on R/S, like GETKEY.
GETKEYA
This function works like the regular GETKEY, except it does not wait for a keystroke if the keyboard buffer is empty, but returns 0 immediately in that case.
GETM
Get matrix. Copies a submatrix into the X-register from the indexed matrix.
GETMI, PUTMI, GETLI, PUTLI
These functions allow direct access to matrix and list elements, that is, without needing to use INDEX and RCLEL/STOEL. All four functions take the matrix or list to be accessed as the argument, e.g. GETMI "MAT", PUTMI IND 00, PUTLI ST Z. The other parameters are taken from the stack, as follows:
GETMI: Expects a row index in Y and a column index in X; pushes the indexed item onto the stack.
PUTMI: Expects a row index in Z, a column index in Y, and an item in X, and stores the item at the specified indices.
GETLI: Expect an index in X; pushes the indexed item onto the stack.
PUTLI: Expects an index in Y and an item in X, and stores the item at the specified index.
Note that none of these functions remove their arguments from the stack. That is a deliberate design decision, intended to make read-modify-write interactions easy to code.
GRAD
Grads angular mode
GROW
Selects Grow mode. Executing → or J+ causes the matrix to grow by one new row if the index pointers are at the last (lower-right) element in the matrix.
GOTO
Go to label. From the keyboard, moves the program pointer to the specified label. In a running program, causes the program to branch to the specified label.

------- H -------

HEAD
Removes and returns the first character or element from the string or list named by the function's parameter. If the string or list is empty, skip the next instruction.
HEXM
Hexadecimal mode
HMS+
Add x and y using H.MMSSss
HMS-
Subtract x from y H.MMSSss

------- I -------

I+
Increments the row pointer in the indexed matrix.
I-
Decrements the row pointer in the indexed matrix.
IDENT
This returns the version of Free42 core used in aabbccdd format, with 3.1.12b being formatted as 3011202, for example.
INDEX
Indexes a named matrix.
INPUT
Recalls a register or variable to the X-register, displays the name of the register or variable along with the contents of the X-register, and halts program execution; pressing [R/S] stores x into the register or variable. (Used only in programs.)
INSR
Insert row. In Matrix-Editor: A new row is inserted at the current position.
INTEG
Integrate
INVRT
Invert matrix in X-register
IP
Return integer part
ISG
Increment, skip if greater. Given ccccccc.fffii in a variable or register, increments cccccce by ii and skips the next program line if ccccccc is now > fff.

------- J -------

J+
Increments the column pointer in the indexed matrix.
J-
Decrements the column pointer in the indexed matrix.

------- K -------

KEYASN
Key-assignments mode for the CUSTOM menu.
KEYG
On menu key, go to. Defines the label to be branched to when a particular menu key is pressed.
KEYX
On menu key, execute. Defines the label to be executed (as a subroutine) when a particular menu key is pressed.

------- L -------

LASTO
Relates to LSTO like ASTO relates to STO.
LASTX
Last x
LBL
Label
LCLBL
Selects Local label mode for the CUSTOM menu.
LCLV
CLV for local variables. LCLV only deletes local variables that were created at the current RTN level, making it safe to use without the risk of deleting local variables from a lower stack level, or global variables. If a local variable with the given name does not exist at the current RTN level, LCLV does nothing, and does not raise an error.
LENGTH
Returns the length of the string or list in X.
LINF
Linear ﬁt model
LINΣ
Selects Linear statistics mode, which uses six summation coefficients.
LIST
Prints a portion of a program listing. (Not programmable.)
LIST?
Tests whether the object in X is a list.
LIST→
Performs the inverse of the →LIST operation.
LN
Natural logarithm
LN1+X
Natural logarithm for values close to zero. Returns ln(1+x), which provides a much higher accuracy in the fractional part of the result.
LNSTK and L4STK
[Big Stack] Local N-level / 4-level Stack. These switch to N-level or 4-level stack mode, respectively, but in addition, they automatically restore the previous stack mode when the current function returns. Further, L4STK saves levels 5 and up in a hidden list, and also restores them when the previous stack mode is restored. (The non-local 4STK function simply discards levels 5 and up.) All of these functions are no-ops when the selected stack mode is already active.
LOCK and UNLOCK
Program locking. When you perform LOCK, the current program is protected against editing. This is indicated by the current line indicator changing from a black triangle to a gray one. You can always make the program editable again later by performing UNLOCK. This feature is meant purely to prevent accidental editing, not to make a program permanently unmodifiable.
LOCK and UNLOCK must be executed in PRGM mode. They affect only the current program, so if you want to lock or unlock multiple programs, you have to do them one at a time.
LOG
Common logarithm
LOGF
Logarithmic ﬁt
LSTO
Can be used to create local variables. These are variables that exist only for the duration of the current subroutine, and are automatically deleted when it returns.
LXASTO
See XASTO

------- M -------

[MIN]
Finds the lowest element of the current column, starting at the current row, of the indexed matrix, and returns the element to X and the row where it was found to Y;
MAN
Manual printing
MAT?
Matrix test. If the X-register contains a matrix, executes the next program line; if the X-register does not contain a matrix, skips the next program line.
[MAX]
Is like [MIN] except it finds the highest element; if the minimum or maximum is not unique (it is found in more than one row), the highest matching row is returned. [MIN] and [MAX] require the indexed matrix to be a real matrix, and they do not allow string elements in the column being searched.
MEAN
Arithmetic mean (average)
MENU
Programmable MENU
MDY
Display, return, and accept dates in month/day/year format
Mixed
See CAPS.
MOD
Modulo. Returns the remainder for y/x.
MVAR
Declares a menu variable.

------- N -------

N!
Factorial
NEWLIST
Returns a new empty list.
NEWSTR
Returns a new empty string. Equivalent to XSTR "".
NEWMAT
New matrix. Creates a (y*x) matrix in the X-register.
NN→S
NN→S works like N→S, except it works as if it's always in ALL mode, and it converts the number with the calculator's full precision — that is, without limiting the mantissa to 12 digits.
NOP
No Operation. Can be used as a filler when ISG is used in a way where it will always skip the next instruction, like when using it as a counter with no upper limit.
NORM
Normal printing
NOT
Logical NOT
NSTK
[Big Stack] N-level Stack. Turns on big stack mode.
N→C
See C→N.
N→S
See S→N.
NN→S
NN→S works like N→S, except it works as if it's always in ALL mode, and it converts the number with the calculator's full precision — that is, without limiting the mantissa to 12 digits.

------- O -------

OCTM
Octal mode
OFF
Turns the calculator off (programmable).
OLD
Recalls the current element from the indexed matrix. (Equivalent to RCLEL.)
ON
Continuous on. Prevents the calculator from automatically turning off after ten minutes of inactivity.
OR
Logical OR

------- P -------

PCOMPLX and RCOMPLX
These functions work like COMPLEX, except PCOMPLX always works in polar mode, and RCOMPLX always works in rectangular mode, regardless of the RECT/POLAR mode setting (flag 73) that is currently in effect. This can be useful when complex constants need to be embedded in programs, allowing such code to work correctly in either mode.
PERM
Permutations of y items taken x at a time. Returns y!/(y — x)! .
PGMINT
Program to integrate
PGMMENU
PGM Menu. Presents a menu of all global labels that have MVAR instructions. When the user makes a selection, the label name is placed in the ALPHA register, and program execution is resumed, similar to the way VARMENU handles a selection. This function allows programs to implement behavior similar to the top-level SOLVER and ∫f(x) menus.
PGMSLV
Program to solve
PGMVAR
Print MVAR variables. This prints all the variables associated with the given LBL through MVAR declarations, in other words, the contents of the VARMENU for that label.
PI
Mathematical constant pi (= 3.14159...)
PICK n and UNPICK n
[Big Stack] Gets the object from level n, or puts an object into level n. Note that UNPICK consumes the contents of level 1, unlike STO, and n refers to the stack level number after X has been dropped. The effect is that you can modify an object at level n by doing PICK n, <modify the object>, UNPICK n, without having to add 1 to the level number for UNPICK. Also note that this is similar to the behavior of PICK and UNPICK in RPL.
PIXEL
Turns on a single pixel (dot) in the display. The (X,Y)-location of the pixel is given by the numbers in the X-and Y-registers. Negative values define lines.
POLAR
Polar mode
POS
Finds the first occurrence of the string or list X in Y. Or with three parameters: find the first occurrence of string or list X in Z, starting the search from position Y.
POSA
Position in Alpha. Searches the Alpha register for the target specified in the X-register. If found, returns the character position; if not found, returns -1.
PRA
Print alpha
PRLCD
Print LCD
PRMVAR
Print MVAR variables. This prints all the variables associated with the given LBL through MVAR declarations, in other words, the contents of the VARMENU for that label.
PROFF
Printing off
PROMPT
Displays the Alpha register and halts program execution.
PRON
Printing on
PRP
Print program
PRREG
Prints the numbered registers.
PRSTK
Print stack
PRUSR
Print user vars and labels
PRV
Print variable
PRX
Print X-register
PRΣ
Print summation registers
PSE
Pauses program execution for about 1 second.
PUTLI, PUTMI
See GETMI
PUTM
Put matrix. Stores the matrix in the X-register into the indexed matrix beginning at the current element.
PWRF
Power ﬁt

------- Q -------

QUIET
Quiet mode. Toggles flag 26 to disable/enable the beeper. (Not programmable.)

------- R -------

RAD
Radians mode
RAN
Returns a random number (0 ≤ x < 1).
RCL
Recalls data into the X-register.
RCL+
Recall addition. Recalls data and adds it to the contents of the X-register.
RCL-
Recall subtraction. Recalls data and subtracts it from the contents of the X-register.
RCL×
Recall multiplication. Recalls data and multiplies it by the contents of the X-register.
RCL÷
Recall division. Recalls data and divides it into the contents of the X-register.
RCLEL
Recall element. Recalls the current matrix element from the indexed matrix.
RCLFLAG
Gets the state of all flags and returns them as a complex number. The real part of this number contains flags 0 through 49, and the imaginary part contains flags 50 through 99, encoded as binary integers with the least significant bits corresponding to the lowest-numbered flags.
RCLIJ
Recall IJ pointers
RCOMPLX
See PCOMPLX
RDX,
Radix comma
RDX.
Radix period
REALRES
Real-results only
REAL?
Real test
RECT
Rectangular mode
REV
Reverse the string or list in X.
RND
Rounds the number in the X-register using the current display format.
RNRM
Row norm
ROTXY
Rotates the 36-bit number in the Y-register by x bits.
RSUM
Row sum
RTN
Return. In a running program, branches the program pointer back to the line following the most recent XEQ instruction. If there is no matching XEQ instruction, program execution halts. From the keyboard, RTN moves the program pointer to line 00 of the current program.
RTNERR n
Return Error from function. Raises an error based on the parameter n, as follows: 0: No Error; 1: Alpha Data Is Invalid; 2: Out of Range; 3: Divide by 0; 4: Invalid Type; 5: Invalid Data; 6: Nonexistent; 7: Dimension Error; 8: Too Few Arguments. Execution is halted on the XEQ that called the function, unless flag 25 was set, in which case flag 25 is cleared and execution continues. If the stack was saved using FUNC, this restores the stack to its initial state. Also accepts a string as error message.
RTNNO
Return from conditional function. To be used by functions that act as conditionals. RTNNO causes the line after the calling XEQ to be skipped, or, if the function was called from the keyboard, it will display the message "No", like a built-in conditional.
RTNYES
Return from conditional function. To be used by functions that act as conditionals. RTNYES is like RTN, except if the function was called from the keyboard, it will display the message "Yes", like a built-in conditional.
R<>R
Row swap row. Swaps the elements in rows x and y in the indexed matrix.
R↑
Roll up
R↓
Roll down
R↓N n and R↑N n
[Big Stack] Rolls levels 1..n down or up. Note that the standard R↓ and R↑ are equivalent to R↓N depth and R↑N depth.

------- S -------

SCI
Scientiﬁc notation
SDEV
Standard deviation. Returns s_x, and s_y, using the current statistical data.
SEED
Seed (for RAN)
SF
Set ﬂag
SIGN
Sign. Returns 1 for x ≥ 0, —1 for x < 0, and 0 for non-numbers. Returns the unit vector of a complex number.
SIN
Sine
SINH
Hyperbolic sine
SIZE
Sets the number of storage registers.
SKIP
Skips the next line, like a test that always tests false. This can be used to invert the sense of tests that have no convenient inverse; for example: REAL? SKIP GTO 42 will jump to LBL 42 if the object in X is not a real number.
SLOPE
Returns the slope of the linear transformation of the current curve-fitting model.
SOLVE
Solve for variable
SQRT
Square root
SST
Single step. Moves the program pointer to the next program line. (Not programmable.)
SST↓
Step Into: Executes one line of code, and if the line in question is a function call, the next line to be executed will be the first line of the function being called. That is, you are Stepping Into the function;
SST→
Step Over: Executes one line of code, and if that line is a function call, it is executed in that one step. You are not Stepping Into the function; rather, you are Stepping Over it.
SST↑
Step Out: Starts program execution, continuing until just after the end of the current function. You are Stepping Out of the function.
STO
Stores a copy of x into a destination register or variable.
STO+
Store addition. Adds x to an existing register or variable.
STO-
Store subtraction. Subtracts x from an existing register or variable.
STO×
Store multiplication. Multiplies an existing register or variable by x.
STO÷
Store division. Divides an existing register or variable by x.
STOEL
Store element. Stores a copy of x into the current element of the indexed matrix.
STOFLAG
Restores the state of all flags that were retrieved using a previous RCLFLAG. Note that this does not affect the following flags: 27 (CUSTOM), 44 (Continuous On), 45 (Solving), 46 (Integrating), 47 (Variable Menu), 48 (ALPHA mode), 49 (Low Battery), 53 (INPUT), 65 (Matrix Editor), and 75 (Programmable Menu). You can also choose to restore only a range of flags. With the saved flags in the Y register, and a number bb.ee in X, only flags numbered bb through ee are restored.
STOIJ
Store IJ pointers
STOP
Stop program
STRACE
Stack Trace mode. This turns on a new print mode, which is a variation on TRACE mode, printing the entire stack instead of just X. This can be a valuable debugging tool, but it generates large amounts of output!
STR?
String test
SUBSTR
From the string or list in Z, gets the substring/sublist starting at index Y and ending at index X. If X and/or Y are negative, they are counts from the end, rather than the beginning. The very end of the string or list can be specified by leaving off the 'end' parameter, i.e. by having the string or list in Y and the starting index in X.
SUM
Recall Σx and Σy
S→N and N→S
Convert string to number or number to string, like ANUM and ARCL.

------- T -------

TAN
Tangent
TANH
Hyperbolic tangent
TIME
Returns the current time in the X register
TONE
Tone (0-9)
TRACE
Trace printing
TRANS
Transpose matrix
TYPE?
Returns an integer, representing the type of the object in the X register. The numbers correspond to object types as follows: 1: Real Number; 2: Complex Number; 3: Real Matrix; 4: Complex Matrix; 5: String; 6: List.

------- U -------

UVEC
Unit vector. Returns the unit vector for the matrix or complex number in the X-register. That is, each element in the vector is adjusted so that the magnitude (Frobenius norm) is equal to 1.
UNPICK n
See PICK n

------- V -------

VARMENU
Variable menu
VARMNU1
Modified version of VARMENU, with two differences: You can select a variable without having to assign any values first, so you don't have to press the menu key twice if all you want to do is make a selection; and also, it catches EXIT, clearing the ALPHA register and resuming program execution when it is pressed.
VIEW
Views the contents of a register or variable.

------- W -------

WMEAN
Weighted mean. Returns the mean of x-values weighted by the y-values: Σxy + Σy.
WRAP
Selects Wrap mode, which prevents the indexed matrix from growing.
WSIZE
(BASE) Sets the word size to the number in the X register, which must be between 1 and 64.
WSIZE?
Returns the current word size.

------- X -------

XASTO and LXASTO
Like ASTO and LASTO, but the entire ALPHA register, not just the first 6 characters.
X<>
Swaps the contents of the X-register with another register or variable.
X<>F
Exchanges flags 0-7 with the X register. The flags are encoded as a binary integer between 0 and 255, with the least significant bits corresponding to the lowest-numbered flags.
X<>Y
x exchange y
XEQ
Execute - XEQ instructions are subroutine calls. A subroutine call is not complete until a RTN or END has been executed to return program execution to the line following the XEQ instruction.
XOR
Exclusive OR
XSTR
Create a string directly in the X register, without needing the ALPHA register and without the six-character limit of ASTO.
XTOA
X to alpha
XVIEW
This function works just like AVIEW, except it takes the text from the X register rather than the ALPHA register, so it doesn't have the 44-character length restriction of AVIEW. XVIEW requires the X register to contain a string. This is not intended as a replacement for VIEW ST X; it's meant to make it possible to display longer messages than what AVIEW can handle.
X²
Square, x²
X=? X≠? X? X≤? X≥?
Compare X to any argument. Similar to X=Y?, X≠Y?, etc., except these functions allow you to compare X to any register or variable, not just to Y.
X2LINE
See A2LINE

------- Y -------

YINT
Y-intercept
Y^X
Power, y^x
YMD
Display, return, and accept dates in year/month/day format

----- Z-etc -----

0=? 0≠? 0? 0≤? 0≥?
Compare any argument to 0. Similar to X=0?, X≠0?, etc., except these functions allow you to compare any register or variable to 0, not just X.
1/X
Reciprocal
10^X
Common exponential, 10x
+
Add
-
Subtract
×
Multiply
÷
Divide
+/-
Change sign
Σ+
Summation plus. Accumulates a pair of x- and y-values into the summation registers.
Σ-
Summation minus. Subtracts a pair of x- and y-values from the summation registers.
ΣREG
Summation registers. Defines which storage register begins the block of summation registers.
ΣREG?
Returns the register number of the first summation register.
4STK
[Big Stack] 4-level Stack. Turns off big stack mode, returning to the TZYX stack.
→DEC
To decimal
→DEG
To degrees
→HMS
To hours-minutes-seconds
→HR
To decimal hours
→LIST
Creates a list from objects on the stack. The number of objects is taken from the X register (level 1), the objects themselves are taken from the levels above X. They are stored in the list in the order in which they were pushed, so the objects from the highest levels come first in the list.
→OCT
To octal
→POL
To polar
→RAD
To radians
→REC
To rectangular
←
Moves left one element in the indexed matrix.
↑
Moves up one element in the indexed matrix.
↓
Moves down one element in the indexed matrix.
→
Moves right one element in the indexed matrix.
%
Percent. Returns (x*y)/100. (Leaves the y-value in the Y-register.)
%CH
Percent change. Returns (x—y)(100/y).