• RPN (Reverse Polish Notation)
• 10-digit LED calculator display, 10^-99 to 10⁺⁹⁹
• Four stack registers with roll down
• Thirty storage registers with arithmetic memory operators:
  • 10 primary registers
  •  6 statistical registers
  • 14 indirect registers
• Math, trigonometric, polar⇔rectangular, sexagesimal⇔decimal, logarithmic, statistical, power and other miscellaneous functions
• Programmable, with labels, subroutines, branching, conditionals, indirect addressing, annotated program listing, and memory for 198 program steps
• Library of Sample Programs
• Fast, slow or single step program execution
• Program import via pasteboard or from other Apps (except Apple TV)
• Program export via printer, email, pasteboard or to others Apps (except Apple TV)
• iTunes program File Sharing (except Apple TV)
• Two additional windows with views of:
  • stack/storage registers
  • paper tape keystroke log
  • program source code
  • program documentation
• Copy-from and Paste-to the calculator display (except Apple TV)
• Simple Paper Tape annotations

Topics

This document is not an exhaustive reference manual; rather, it's a terse outline of the calculator's function and programming keys. I have structured this information so that prerequisite material generally comes first, thus, you are encouraged to read the topics sequentially.

In this document normal calculator keys are shown in bold, such as +, or CHS, or 4, or Σ+. Most keys can perform two other functions, however, one labeled in blue and and one labeled in gold. To execute one of these functions you first touch the corresponding colored prefix key, either r or t, followed by the desired function key.

So to compute the sine of a number you'd touch two keys, the f prefix key followed by the 4 key. However, this document will simply show the key as sin: the font color implies which prefix character is used. Similarly, touching the two keys g and 4 executes the inverse sine function sin^-1. The only exception to this convention is when discussing programming and keycodes.

The PRGM-RUN switch controls the two basic calculator modes. In RUN mode, key presses are executed immediately and results are shown in the calculator display area. In PRGM mode, key presses are stored in program memory for later execution. It's important to realize which mode the calculator is in, as it has ramifications that affect other operational characteristics of the device.

(As you'll learn later there are two variants of RUN mode, for three actual calculator modes.)

Topics

To get the feel of your new calculator, try a few simple calculations. First, perform these operations:

• Set the ON-OFF switch to ON.
• Set the PRGM-RUN switch to RUN.
• Press Q 2 so the display will match the examples.

To calculate the surface area of a sphere, the formula `A_(surface)=pid^2` can use used, where d is the diameter of the sphere. Ganymede, one of Jupiter's 12 moons, has a diameter of 3,200 miles. You can use the calculator to manually compute the area of Ganymede in square miles. Merely press the following keys in order:

Press	Display
3200	3200.
!	10240000.00
%	3.14
?	32169908.77

Topics

After calculating the surface area of Ganymede, one of Jupiter's 12 moons, suppose you decided you wanted the surface area of each moon. You could repeat the procedure you used for Ganymede 12 times, using a different diameter d each time; however, an easier and faster method is to create a program that will calculate the surface area of any sphere from its diameter rather than pressing all the keys for each moon.

To calculate the area of a sphere using a program, you should first write the program, then you must load the program into the calculator, and finally you run the program to calculate each answer.

1. Writing the Program. You have already written it! A program is nothing more than the series of keystrokes you would execute to solve the same problem manually . Two additional operations, a label and a return are used to define the beginning and end of the program.

2. Loading the Program. To load the keystrokes of the program into the calculator:
   • Slide the PRGM-RUN switch to PRGM.
   • Press _X to clear the calculator.
   • Press these keys in order. (When you are loading a program, the display gives you information that you will find useful later, but which you can ignore for now.)

   © 0
   !
   %
   ?
   §

   The calculator will now remember this keystroke sequence.

3. Running the Program. To run the program to find the area of any sphere from its diameter:
   • Slide the PRGM-RUN switch to RUN.
   • Key in the value of the diameter.
   • Press ¦ 0 to run the program.

   When you press ¦ 0, the sequence of keystrokes you loaded is automatically executed by the calculator, giving you the same answer you would have obtained manually. So now, in short order, you can calulate the surface areas of Io (2310 miles), Europa (1950 miles) and Callisto (3220 miles):

   Press	Display
   2310 ¦ 0	16763852.56
   1950 ¦ 0	11945906.07
   3220 ¦ 0	32573289.27

Topics

The GO-29 LED window acts as a display area, as well as a touch sensitive input area that initiates further activities not available on an actual HP-29C. The calculator display is also modal, so what it displays and how it reacts to touches depends on the setting of the PRGM-RUN switch.

A similar concept exists for Apple TV, based on focus navigation rather than touch, see the section GO-29 and Apple TV for details.

Topics

Automatic storage of intermediate results is the reason that GO-29 slides so easily through the most complex equations. The displayed X register, which is the only visible register in the calculator display, is one of four registers inside the calculator that are positioned to form the automatic memory stack. We label these registers X, Y, Z, and T. They are "stacked" one on top of the other with the displayed X register on the bottom and T at the top.

Topics

In addition to the automatic storage of intermediate results that is provided by the four-register automatic memory stack, the calculator also has 30 addressable data storage registers that are unaffected by operations within the stack. These storage registers allow you to manually store and recall constants or to set aside numbers for use in later calculations. Like all functions, you can use these storage registers either from the keyboard or as part of a program. All 30 storage registers reside contiguously in Continuous Memory and maintain their contents even when the calculator is turned OFF.

The diagram below shows all storage registers. The addresses of the primary storage registers are indicated by the numbers 0 through 9 and by .0 through .5. The addresses of the indirect storage registers are indicated by the numbers (16) through (29). Storing and recalling numbers in the 14 indirect storage registers is explained in section Using the R₀ Register for Indirect Control.

Topics

GO-29 provides two distinct, scrollable, views of the calculator's internal state unavailable on the real hardware. This makes using the calculator, and programming and debugging code much easier. Access to this additional information is controlled by a double-tap on the calculator display. If the information view is visible, a double-tap hides the view. If the view is not visible, the information view appears. So a double-tap of the calculator display toggles the visibility of the available auxiliary information.

Similar to single-tapping the calculator display, the information that's displayed in response to a double-tap is dependent on the setting of the PRGM-RUN switch.

(Note: unlike for iPhone and iPod touch, which have tiny screens, on Mac and iPad both information views are by default always visible, but you can hide them with two double-taps, if desired, one in PRGM mode and one in RUN mode. For Apple TV the information views are always visible and cannot be hidden.)

Both auxiliary information views include this touch point that toggles what the view shows, detailed in the following two sections.

Topics

• Recovering From Mistakes

  In addition to the four stack registers that automatically store intermediate results, the calculator also contains a separate automatic register, the Y register. This register preserves the value in the displayed X register before a new function is performed.

• Prefix Clear

  The _Z key will clear a blue prefix key t, a gold prefix key r , STO, RCL, or GTO. To clear a prefix you have mistakenly pressed, merely press _Z, then press the correct key.

• Absolute Value

  Some calculations require the absolute value, or magnitude, of a number. To obtain the absolute value of the number in the display, press @.

• Integer Portion

  To extract and display the integer portion of a number, press n. The fractional portion of the number is lost. The entire number, of course, is preserved in the Y register.

• Fractional Portion

  To place only the fractional portion of a number into the displayed X-register, press M. The integer portion of the number is lost. The entire number, of course, is preserved in the Y register.

• Reciprocals

  To calculate the reciprocal of a number in the displayed X register, press O.

• Square Roots

  To calculate the square root of a number in the displayed X register, press m.

• Squaring

  To square a number in the displayed X register, press !.

• Using Pi

  The value % accurate to 14 places (3.14159265358979) is provided as a fixed constant in GO-29. Merely press % whenever you need it in a calculation.

• Percentages

  The I key is a two-number function that allows you to compute percentages. To find the percentage of a number:

  1. key in the base number
  2. press z
  3. key in the number representing percent rate
  4. press I

  For example, to calculate the sales tax on a purchase, the purchase price is the base number and the sales tax is the percentage rate.

  When I is pressed, the calculated answer writes over the percentage rate in the X register, and the base number is preserved in the Y register. Since the purchase price is now in the Y register and the amount of tax is in the X register, the total amount can be obtained by simply adding.

• Trigonometric Functions

  The calculator provides you with six trigonometric functions. It also calculates angles in decimal degrees, radians, or grads; and it converts between decimal degrees and degrees, minutes, seconds. Use P, { or } to specify the degree mode.

  Note: 360 degrees = 2π radians = 400 grads.

  The six trigonometric functions provided by the calculator are:

  • j (sine)
  • K (inverse sine)
  • k (cosine)
  • L (inverse cosine)
  • l (tangent)
  • B (inverse tangent)

  Each trigonometric function assumes angles in decimal degrees, radians, or grads. Trigonometric functions are one-number functions, so to use them you key in the number, then press the function key.

• Hours (or Degrees), Minutes, Seconds / Decimal Conversions

  The T (to hours (or degrees), minutes, seconds) key converts decimal hours to the format of hours, minutes and seconds, or converts angles specified in decimal degrees to degrees, minutes, seconds. These hour and degree values are based on the sexagesimal (base 60) number system. When a time (or angle) is displayed in hours (or degrees), minutes, seconds format, the digits specifying hours (or degrees) occur to the left of the decimal point, while the digits specifying minutes, seconds, and fractions of seconds occur to the right of the decimal point. To see all these digits you should specify Q 5 display format. For example, the decimal number 89.29047° displays as 89°, 17′, 25.7″ in H.MS format:

  

  Conversely, the $ (to decimal hours (or degrees)) key is used to change hours (or degrees), minutes, seconds into decimal hours (or degrees).

  The $ and T keys are important because the calculator's trigonometric functions operate on angles in decimal degrees, but not in degrees, minutes, seconds. In order to calculate any trigonometric function of an angle given in degrees, minutes, seconds, you must first convert the angle to decimal degrees.

• Polar/Rectangular Coordinate Conversion

  Two functions H and o are provided for polar/rectangular coordinate conversions. Polar angle θ is assumed in decimal degrees, radians, or grads, depending upon the trigonometric mode selected by P, {, or }.

  To convert values in the X and Y registers representing rectangular (x, y) coordinates, respectively, to polar (r, θ) coordinates, magnitude and angle, respectively, press →P. Magnitude r then appears in the X register and angle θ is placed in the Y register.

  Conversely, to convert values in the X and Y registers representing polar (r, θ) coordinates, respectively, to rectangular coordinates (x, y), press →R. Coordinate x then appears in the X register and coordinate y is placed in the Y register.

• Logarithm and Exponential Functions

  The calculator computes both natural and common logarithms as well as their inverse functions (antilogarithms):

  • u is log_e (natural log). It takes the log of the value in X to base e (2.718...).
  • F is antilog_e (natural antilog). It raises e (2.718...) to the power of the value in X. (To display the value of e, press 1 F.)
  • i is log₁₀ (common log). It computes the log of the value in the X register to base 10.
  • G is antilog₁₀ (common antilog). It raises 10 to the power of the value in the X register.

• Raising Numbers to Powers

  The p key is used to raise numbers to powers. This function raises a positive real number to any real power; that is, the power may be positive or negative, and it may be an integer, a fraction, or a mixed number. p also permits you to raise any negative real number to the power of any integer within the calculating range of the calculator.

  In conjunction with O, p provides a simple way to extract roots. For example, the cube root of 5 is equivalent to 5^1/3 e.g.:

  5 z

  3 O

  p

• Statistical Functions
  • Accumulations
    Pressing the g key automatically gives you several different sums and products of the values in the X and Y registers at once. In order to make these values accessible for sophisticated statistics problems, they are automatically placed by the calculator into storage registers R.₀ through R.₅ . The only time that information is automatically accumulated in the storage registers is when the g key is used. Before you begin any calculations using the g key, you should first clear the storage registers of data by pressing _¥.

    When you press the g key each of the following operations are performed on the data in the X and Y registers:

    • The number in X is added to the contents of storage register R.₁.
    • The square of the number in X is added to the contents of storage register R.₂.
    • The number in Y is added to the contents of storage register R.₃.
    • The square of the number in Y is added to the contents of storage register R.₄.
    • The number in X is multiplied by the contents of the Y register, and the product added to storage register R.₅.
    • The number 1 is added to storage register R.₀, and the total number in R.₀ is then written into the display. The stack does not lift.

    The number that you keyed into the X register is preserved in the Y register, while the number in the stack Y register remains in the Y register.

    Thus, each press of the Σ+ key updates these summations and multiplications. The contents of the displayed X register and the applicable storage registers are as follows:

    • R.₀ = X is n, the number of entries.
    • R.₁ is Σx, summation of x values.
    • R.₂ is Σx², summation of x² values.
    • R.₃ is Σy, summation of y values.
    • R.₄ is Σy², summation of y² values.
    • R.₅ is Σxy, summation of products of x and y values.

    Again, before you begin any calculations using the g key, you should first clear the storage registers of data by pressing _¥.

    There is a special flavor of storage register recall f g that summons only Σx and Σy, and stores them in X and Y, respectivfely, overwriting the contents of those two registers. The stack does not lift. (This feature is particularly useful when performing vector arithmetic, discussed shortly.)

    To recall any of the summations individually at any time, you can recall the contents of the desired storage register into the X register by pressing f followed the number key of the storage register address .₀ though .₅. After you have pressed g, recalling storage register contents or keying in another number writes over the number of entries (n) that is displayed. The stack does not lift.

  • Mean
    The A (mean) key calculates the arithmetic average of x and y accumulated in registers R.₁ and R.₃, respectively, according to these formulae: x̄ = `frac{1}{n}sum_(i=1)^nx_i`     ȳ =`frac{1}{n}sum_(i=1)^ny_i`

    The resultant values for x̄ and ȳ are available on the stack, in the X and Y registers, respectively.

  • Standard Deviation
    The S (standard deviation) key computes a measure of dispersion around the mean by using data accumulated in the storage registers R.₀ through R.₅, according to these formulae: `s_(x)=sqrt(frac{sumx^2-(sumx)^2/n}{n-1})`     `s_(y)=sqrt(frac{sumy^2-(sumy)^2/n}{n-1})`

    The resultant values vaues for s_x and s_y are available on the stack, in the X and Y registers, respectively.

    Note: a population standard deviation is computed from the sample standard deviation by:

    `sigma=ssqrt(frac{n-1}{n})`

  • Deleteing and Correcting Summation Data
    If you key in an incorrect value and have not pressed Σ+, press CLX and key in the correct value.

    If one of the values is changed, or if you discover after you have pressed the Σ+ key that one of the values is in error, you can correct the summations by using the D key as follows:

    1. Key the incorrect data pair into the X and Y registers. (You can use Y to return a single incorrect data value to the X register.)
    2. Press D to delete the incorrect data.
    3. Key in the correct values for x and y. (If one value of an X,Y data pair is incorrect, both values must be deleted and reentered.)
    4. Press g.

    The correct values for mean and standard deviation are now obtainable by pressing A and S.

• Vector Arithmetic
  You can add or subtract vectors by combining the polar/ rectangular conversion functions (the H and o keys) with the summation functions (the g and D keys).

  For an example of this, examine the Sample Program Apeneck Sweeney as he flies the Swordfish into a crossing headwind.

Topics

There are three ways to use your GO-29 calculator:

1. Manual RUN Mode
   The functions and operations you have learned about in previous sections are performed manually one at a time with the PRGM-RUN switch set to RUN. These functions combined with the automatic register stack enable you to calculate any problem with ease.
2. PRGM Mode
   In PRGM mode the functions and operations you have learned about are not executed, but instead are recorded in a part of the calculator called program memory for later execution. All operations on the keyboard except the following can be recorded for later execution while in PRGM mode:
   • SST - single-step foreward through program memorey
   • w - backward-step through program memory
   • e . n n or the GO-29 extension e + n n n - position step pointer to designated step number
   • ¬ - deletes current step from program memory
   • _X - clears all 198 steps of program memory
   • _Z - cancels r, t, STO, RCL or GTO
   These operations work in PRGM mode to help you write, record and edit your programs from the keyboard.
3. Automatic RUN Mode
   The calculator can also be used to automatically execute a list of operations with the PRGM-RUN switch set to RUN if they have previously been recorded in program memory. Instead of your having to press each key manually, the recorded operations are executed sequentially in automatic RUN mode when you press GTO, GSB or R/S (run /stop). You press only one key and the entire list of recorded operations is executed much more quickly than you could have executed them yourself.

Topics

A program is nothing more than a series of calculator keystrokes that you would press to solve a problem manually. The calculator remembers these keystrokes when you key them in, then executes them, in order, whenever you wish. You've already seen this demonstrated in the section Programmed Problem Solving, which you may wish to review.

All HP-29C programming techniques work with GO-29, although this App has some useful extensions. The first is the amount of program memory available for storing the keystrokes that define your program, now increased to 198 steps. When you set the calculator to PRGM mode you can examine the contents of program memory; logically, here is how the surface area program `A_(surface)=pid^2` is stored:

Each step of program memory can store a single operation, whether that operation consists of one, two, three, or four keystrokes. Thus, one step of program memory might contain a single-keystroke operation like CHS, while another step of program memory could contain a two-keystroke operation, like STO 6. Step 01 of program memory currently contains an operation that requires three keystrokes, t GTO 0, which we understand to be © 0.

However, what is actually stored in program memory are not instruction mnemonics, but rather keycodes, discussed now.

Topics

You can tell from the display what keystrokes are loaded into each step of program memory by means of the keycodes for those keys. Let's look at some keycodes now. If you have cleared the surface area of a sphere program illustrated in the section Programmed Problem Solving, please reenter it now before continuing.

With the calculator in PRGM mode, press the 4 keys e . 0 0 (go to step number 00) to return the calculator to the beginning of program memory. The number that you see on the left side of the display indicates the step number of program memory to which the calculator is set. You should be set at step 00, indicated by a display of 00. Now we'll use the q (single-step) key to examine the next step of program memory. q lets you step through program memory, one program step at a time.

Press	Display
SST	01 15 13 00

The calculator is now set to step 01 of program memory, as indicated by the number 01 that you see on the left side of the display. The other numbers in the display are as many as three two-digit keycodes for the keystrokes that have been loaded into that step of program memory.

Each key on the calculator has a keycode. For each keycode, the first digit denotes the row of the key on the keyboard and the second digit identifies the column of the key in that row (there are 7 rows of keys, and 4-5 columns of keys per row). Always count from the top down, and from left to right. Each key, even the double-wide z key, counts as one keystroke.

For convenience, digit keys are identified by two digit keycodes of 00 through 09, except when prefixed by r or t. When preceeded by either of these prefix keys the digit keys are identified by the row-column keycode.

Now use the SST key again to examine the keycodes in the next step of the program:

Press	Display
SST	02   15 63

This table should help explain the keycodes for steps 01 and 02. For step 01 the first two key presses are located by row-column intersection, and the simulator recognizes them as the © mnemonic. The third key press is a simple number 0 key so it is mapped to its two-character numeric keycode, there is no row-colum mapping, and all three keys are merged into one step. In contrast, both step 02 keycodes use row-column intersection to locate the key press, even the number 2 key because it is prefixed by t, and the 2 keys merge into the single step !.

GO-29 provides four extended keycodes, the 8* series, named because they assume the existence of an 8th row of calculator keys. Because there are no such keys, these opcodes are inserted using a contectual menu activated from the program listing auxiliary view. The new instructions, DMP, BEL, SEC and RND are explained in the section Special 8* Opcodes.

Topics

The programming keys described in this section help you write, edit and run programs. Specifics depend upon which of the three calculator modes you are using.

1. PRGM Mode
   These keys are never recorded in program memory:
   • e . n n or the GO-29 extension e + n n n
     Goto positions the internal step pointer to an explicit step number.
   • SST
     Single step advances the step pointer forward for examining and/or changing program steps.
   • BST
     Back step moves the step pointer backwards for examining and/or changing program steps.
   • ¬
     Deletes the current instruction from program memory. All subsequent instructions move up one step in program memory.
   • _X
     Clears all 198 program memory steps to R/S instructions and resets the step pointer to step 00.
   • _Z
     Cancels r, t, STO, RCL or GTO.
2. Manual RUN Mode
   • e . n n or the GO-29 extension e + n n n
     Goto positions the internal step pointer to an explicit step number without executing instructions.
   • GTO followed by a label number 0 through 9, or indirect label ¤ (described in section Using the R₀ Register for Indirect Control)
     Goto searches downward through program memory to first designated label and sets step pointer without executing instructions.
   • GSB followed by a label number 0 through 9, or indirect label ¤ (described in section Using the R₀ Register for Indirect Control)
     Goto subroutine searches downward through program memory to first designated label and starts executing instructions.
   • §
     Return sets the step pointer to 00 without executing instructions.
   • SST
     Single step displays the step number and keycode of the current program memory step when pressed; executes instruction, displays result, and moves to next step when released.
   • BST
     Back step displays the step number and keycode of the previous program memory step when pressed; moves to previous step when released - the program is not run in reverse.
   • R/S
     Run/Stop. Begins execution of a stored program from the current step pointer. Stops execution if program is running.
   • ¬
     Clears t prefix key.
   • _X
     Clears r prefix key.
   • _Z
     Cancels r, t, STO, RCL or GTO.
3. Automatic RUN Mode
   • GTO followed by a label number 0 through 9, or indirect label ¤ (described in section Using the R₀ Register for Indirect Control)
     Goto searches downward through program memory to first designated label and continues executing instructions.
   • GSB followed by a label number 0 through 9, or indirect label ¤ (described in section Using the R₀ Register for Indirect Control)
     Goto subroutine searches downward through program memory to first designated label and executes that section of memory as a subroutine.
   • §
     Return. If executed as a result of pressing GSB and a label designator or execution of a GTO instruction, stops execution and returns control to keyboard. If executed as a result of a GSB instruction, returns control to next step after the GSB instruction.
   • PAUSE
     Pause. Stops program execution for 1 second and displays contents of the X register, then resumes program execution.
   • R/S
     Run/Stop. Stops program execution.
   • Conditionals   R   b   ®   ¯   #   N   °   [
     These instructions make tests and branch instruction flow accordingly, and are discussed in the section Branching.

Topics

The section Programmed Problem Solving provided a concise overview of how to write, load and run our surface area of a sphere program. Let's delve deeper into those topics.

Topics

Editing a program in PRGM mode consists of four basic maneuvers: clearing stuff, positioning the step pointer to an instruction of interest, deleting instructions at the step pointer, and inserting new instructions after the step pointer. GO-29 adds "full screen" editing to the mix, which deletes and rearranges instructions.

1. Clearing stuff
   
   • In PRGM mode, _X clears all 198 program memory steps to R/S instructions and resets the step pointer to step 00.
   • _Z cancels r, t, STO, RCL or GTO.
2. Positioning the Step Pointer
   • e . n n or the GO-29 extension e + n n n
   • SST single step
   • BST back step
   • RTN in RUN mode sets the step pointer to step 00
3. Deleting Instructions
   The ¬ key erases the instruction at the current step of program memory, and all subsequent instructions in program memory move upward one step. An R/S instruction drops in to fill the vacated step 198.
4. Inserting Instructions
   If you press a recordable operation, it will be loaded in the next step of program memory, and all subsequent instructions will be "bumped" down one step in program memory. Program step 198 is lost off the end of program memory. You should always view the contents of the last few steps of program memory before adding instructions to a program to ensure that no vital instructions disappear.
5. Editing the Program Listing (unavailable on Apple TV)
   The program listing auxiliary window has a special Edit (Done) button on step 00 that enables removal and re-arrangement of program steps.

   

   Touching the red minus removes that program step and adds a R/S at step 198. Touching and dragging a gripper pad moves that program step, re-inserting it when you have reached the destination and released the gripper.

Topics

We have used e . n n or the GO-29 extension e + n n n to help edit our programs. This form of GTO cannot be recored as part of program, but there is a variant which can: GTO followed by a label designator 0 - 9, or the indirect label ¤ (described in section Using the R₀ Register for Indirect Control).

• Unconditional
  When the calculator is executing a program and encounters a GTO n instruction, for example GTO 1, it immediately halts execution and begins searching sequentially downward through program memory for that label. When the first © 1 instruction is then encountered, execution begins again.
• Conditional
  Each conditional operator tests the value in the X register against that in the Y register or 0 as indicated. If true, the calculator executes the instruction in the next program memory step. If false, the calculator skips the next step and continues execution after the skipped program step. This is the "Do if TRUE" rule, and GTO is the most commonly done instruction after one of these tests. This will branch program execution to another section of program memory if the conditional test is true: R   b   ®   ¯   #   N   °   [  

Topics

There may be occasions when you want a program to halt during execution so that you can key in data, or to pause so that you can quickly view results before the program automatically resumes running. Other interruptions may be an overt keyboard action on your part, or even a runtime error such as divsion by zero or arithmetic overflow.

• R/S
  The run/stop function can be used either as an instruction in a program or pressed from the keyboard. When pressed from the keyboard, if a program is running, R/S stops the program. If a program is stopped or not running and the calculator is in RUN mode, R/S starts the program running beginning with the current location in program memory. You can use these features to stop a running program at points where you want to key in data. After the data has been keyed in, restart the program using the R/S key from the keyboard.
• U
  The pause function suspends program execution for one second. You can stack multiple pauses to lengthen the delay time, or use the Program Run Speed Settings option to delay between every program step.
• Error Stop
  If the calculator attempts to execute any error-causing operation during a running program, execution immediately halts and the calculator displays the word Error. To see the step number and keycode of the error-causing instruction, you can briefly set the calculator to PRGM mode, or simply examine the program listing window. Press v to clear the error. You can then resume program execution by pressing R/S from the keyboard in RUN mode.

Topics

Often, a program contains a certain series of instructions that are executed several times throughout the program. When the same set of instructions occurs more than once in a program, it can be executed as a subroutine. A subroutine is selected by the ¦ operation, followed by a label designator 0 - 9, or the indirect label ¤ (described in section Using the R₀ Register for Indirect Control).

Topics

The R₀ register is special. Using R₀ in conjunction with other instructions, you can specify the storage register addresses of STO and RCL, and the label addresses of GTO and GSB. By storing a negative number in R₀, you can even transfer execution to any step number of program memory. The « and ª instructions permit you to increment (add 1 to) or decrement (subtract 1 from) the current value in R₀. These are features that you will find extremely useful in controlling loops.

The ª (decrement R₀, skip if zero) instruction subtracts 1 from the contents of the R₀, then tests to see if the register is 0. (A number between +1 and -1 tests as zero.) If R₀ is greater than zero, execution continues with the next step of program memory. If R₀ is zero, the calculator skips one step of program memory before resuming execution. « works similarly except, of course, it increments R₀. For an example, see Manhattan.

Topics

You have seen how the value in R₀ can be altered using the STO, « and ª operations. But the value contained in R₀ can also be used to control other operations. The indirect function ¤, combined with certain other functions allows you to control those functions using the current number in R₀. ¤ uses the number stored in R₀ as an address.

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GO-29 supports six special opcodes not available on a real HP-29C. These are collectively known as the 8* series of instructions, named because they exist on a theoretical 8th row of calculator keys having an infinite number of columns. You cannot key these instructions in, but they can be typed as part of a program imported into the calculator. Or, in PRGM mode, if you touch and hold a program listing step, a contextual menu appears so you can add extended GO-29 opcodes. See the section on keycodes for background information.

1. DMP (80) dumps the step pointer and the stack and memory registers to the paper tape for debugging.
2. BEL (81) sounds a tram bell.
3. BEL (14 81) sounds BEL1 (win).
4. BEL (15 81) sounds BEL2 (lose).
5. SEC (82) stores the second of the day 0 - 86,399 in X, handling the stack just like an RCL.
6. RND (83) replaces X with a random integer 0 < abs(X) < 2³², without otherwise changing the stack.

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A GO-29 program can exist by itself, a simple stream of step numbers and instructions, just like an HP-29C program, or it can be bundled with its documentation in a structure called a Program Package. These descriptive comments can be simple Text, or expressive HTML markup.

A Program Package is really easy to maintain, it's just a file (ASCII or UTF-8 Unicode), and consists of two parts: the documentation at the top / beginning, immediately followed by the program. That's it. Simple enough to manage in most any editor you choose.

Generally, it's useful to associate a name with a program, and GO-29 tries to extract the name from the documentation as the program is being read into memory. If you provide no documentation at all, or do not adhere to the following prescribed naming rule, then Untitled-go29.txt is used.

While the program is being read into memory GO-29 is also scanning the documentation to determine if it's plain Text or rich HTML, by searching for a case-insensitive <html> / </html> tag pair. This defines the start and end of the HTML documentation; if those two strings are not found then the documentation is assumed plain Text.

Finally, the prescribed program naming rule is:

• you get to pick the actual name of the program, even including spaces
• you must suffix the characters "-go29" to the chosen program name
• and you must suffix an extension, either ".txt" or ".html"

Note: The extension does not specify whether the program documentation is Text or HTML, it simply reminds humans what the document contains, and reminds computers that the program is an editable file.

        
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="Content-Style-Type" content="text/css">
<meta name="viewport" content="initial-scale=1.0" />
        

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Note: For Apple TV this section is not applicable.

• To export a program to Files select Share PRGM from this menu:
  1. Open In Another App
  2. Save to Files, which runs Files
  3. Navigate to the destination folder
  4. Add
• To import a program from Files:
  1. First run the Files App
  2. Naviagte to the desired folder
  3. Long touch the desired program to display the Action menu
  4. Share
  5. Copy to GO-29, which runs GO-29
  6. This displays the standard Import PRGM menu with your desired program as one of the items, select the program

Additional help is available in the following sections Importing Programs and Sharing Programs.

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If you enable the Settings option Persist Program Registers, when a program is shared (saved) all the device register values are saved with it. Subsequently, when you import (open) that program device registers are restored to their previously saved values. This behavior is implemented via a special comment in the program's documentation of the form:

Inside the Registers element is a list of comma-separated double precision numbers: 4 for the stack X, Y, Z and T registers, 1 for the LAST X register, and n numbers for the memory registers, where n = 10 for GO-25 and n = 30 for GO-29.

Of course, nothing prevents you from editing the registers list manually; for instance, this list for GO-25

presets the device registers to this:

If there are registers you do not want to preset then leave their value in the list empty; for instance this list initializes all registers excluding the 4 stack registers:

Notes:

• A number is a signed integer or float, with or without a signed exponent, e.g. -1.23e-45, 3.1415, -21, etcetera.
• The case-insensitive Registers element is a single line in the form of a comment, thus must occur after a semicolon for text documentation, or be part of an HTML comment for HTML documentation.
• If multiple Registers elements are encountered then the last takes precedence.

Topics

Note: For Apple TV this section is not applicable, see GO-29 and Apple TV.

On an actual HP-29C programs are entered using the calculator keys. That method works with GO-29 as well, but it's often easier to edit your programs in another App and import them into GO-29 (activate the Import menu by touching the calculator's display in PRGM mode). For instance, you can use Mail to write your program, then copy the program to the pasteboard, switch to GO-29, and import the pasteboard data. As a bonus, when you are finished editing the program simply email it to yourself for later filing in your GO-29 programs folder.

You also have a My Programs container that uses iTunes File Sharing to sync programs between your computer and GO-29.

Preferably, Apps like Files use the iOS Document Model and have a menu to open their documents in another App (labelled variously as Add to appName, Copy to appName, Open in appName, or Save to appName). If such an App sends a program (named, say, Surface Area Of Sphere-go29.txt) to GO-29, that program's name appears in the Import PRGM window.

Finally, a small selection of programs is included in GO-29's Sample Programs container.

For macOS, in PRGM mode, you can also import a program using the File menu item Open.

Topics

Note: For Apple TV this section is not applicable.

You can export a program in various ways using the Share PRGM menu item (activate the Share menu by touching the calculator's display in PRGM mode). Besides the pasteboard, email and printing, you also have a My Programs container that uses iTunes File Sharing to sync programs between your computer and GO-29.

Preferably, GO-29 also supports the iOS Document Model and allows other Apps to open its program files via the Open In Another App menu item. When sending a program to another App, GO-29 uses the program name to identify the program. For example, use this option to export a program to the Files App.

For macOS, in PRGM mode, you can also export a program using the File menu item Save.

Topics

Programs you may copy to the pasteboard and then import into GO-29 while in PRGM mode. Also, do check out the more complex and extensive repertoire of Sample Programs available from the Import PRGM menu.

; Accountant-go29.txt
;
; Compute tax based on income. 17.5% nominal,
; 20% if you earn more than $10,000.
;
; Usage:
;   X = taxable amount
;   GSB 1
;
01 15 13 01 ; LBL 1
02 14 11 02 ; FIX 2
03       33 ; EEX
04       04 ; 4
05       21 ; Swap xy
06    14 51 ; x>y
07    13 02 ; GTO 2
08       01 ; 1
09       07 ; 7
10       73 ; .
11       05 ; 5
12    13 03 ; GTO 3
13 15 13 02 ; LBL 2
14       02 ; 2
15       00 ; 0
16 15 13 03 ; LBL 3
17    15 21 ; %
18    15 12 ; RTN
19       74 ; R/S
                    

; Dice-go29.txt
;
; This program simulates the throwing
; of a pair of dice, pausing to
; display first the value of one die
; (an integer from 1 to 6) ; and then
; pausing to display the value of the
; second die (another integer from 1
; to 6). Finally the values of the two
; dice are added together to give the
; total value of the throw.
;
; The heart of the program is a
; pseudo random number generator that
; is executed first as a subroutine
; and then as part of the main
; program. When you key in a first
; number, called a seed and press
; GSB 1, the digit for the
; first die is generated and displayed
; using the LBL 2 routine as a
; subroutine. Then the digit for the
; second die is generated using the
; same routine as part of the main
; program. The program then uses the
; generated number as a new seed for
; successive throws of the dice.
;
01 15 13 01 ; LBL 1
02 14 11 02 ; FIX 2
03    23 00 ; STO 0
04 15 13 00 ; LBL 0
05       00 ; 0
06    23 01 ; STO 1
07    12 02 ; GSB 2
08 15 13 02 ; LBL 2
09    24 00 ; RCL 0
10       09 ; 9
11       09 ; 9
12       07 ; 7
13       61 ; X
14    15 62 ; FRAC
15    23 00 ; STO 0
16       06 ; 6
17       61 ; X
18       01 ; 1
19       51 ; +
20    14 62 ; INT
21 14 11 00 ; FIX 0
22    14 74 ; PAUSE
23 23 51 01 ; STO + 1
24    24 01 ; RCL 1
25    15 12 ; RTN
26    13 00 ; GTO 0
27    15 12 ; RTN
28       74 ; R/S
                    

; DiceRND-go29.txt
;
; Just like Dice-go29.txt, this program
; uses a pseudo random number generator
; to simulate throwing a pair of dice.
; Please read the program documenttion
; for the real Dice to learn how this
; program flows.
;
; The salient difference is DiceRND uses
; GO-29's builtin RND function rather
; than rolling its own, hence reducing
; the memory footprint.
;
; RND step 09 replaces Dice steps 9-17.
;
01 15 13 01 ; LBL 1
02 14 11 00 ; FIX 0
03 15 13 00 ; LBL 0
04       00 ; 0
05    23 01 ; STO 1
06    12 02 ; GSB 2
07 15 13 02 ; LBL 2
08       06 ; 6
09       83 ; RND replaces Dice steps 09-17
10       01 ; 1
11       51 ; +
12    14 62 ; INT
13    14 74 ; PAUSE
14 23 51 01 ; STO + 1
15    24 01 ; RCL 1
16    15 12 ; RTN
17    13 00 ; GTO 0
18    15 12 ; RTN
19       74 ; R/S
                    

; Fibonacci-go29.txt
;
01 15 13 02 ; LBL 2
02 14 11 02 ; FIX 2
03       34 ; CLX
04    23 00 ; STO 0
05       01 ; 1
06    23 01 ; STO 1
07    14 74 ; PAUSE
08 15 13 00 ; LBL 0
09    24 00 ; RCL 0
10    24 01 ; RCL 1
11       51 ; +
12    14 74 ; PAUSE
13    23 00 ; STO 0
14    24 00 ; RCL 0
15    24 01 ; RCL 1
16       51 ; +
17    14 74 ; PAUSE
18    23 01 ; STO 1
19    13 00 ; GTO 0
20    15 12 ; RTN
21       74 ; R/S
                    

; Fibonacci Rapid Reverse Branching-go29.txt
;
; Usage:
;   GSB 1
;
01    23 01 ; STO 1
02    24 01 ; RCL 1
03    24 02 ; RCL 2
04       51 ; +
05    14 74 ; PAUSE
06    23 02 ; STO 2
07    13 22 ; GTO i
08    15 12 ; RTN
09       74 ; R/S
10       74 ; R/S
11       74 ; R/S
12       74 ; R/S
13       74 ; R/S
14       74 ; R/S
15       74 ; R/S
16       74 ; R/S
17       74 ; R/S
18       74 ; R/S
19       74 ; R/S
20       74 ; R/S
21       74 ; R/S
22       74 ; R/S
23       74 ; R/S
24       74 ; R/S
25       74 ; R/S
26       74 ; R/S
27       74 ; R/S
28       74 ; R/S
29       74 ; R/S
30       74 ; R/S
31       74 ; R/S
32       74 ; R/S
33       74 ; R/S
34       74 ; R/S
35       74 ; R/S
36       74 ; R/S
37       74 ; R/S
38       74 ; R/S
39       74 ; R/S
40       74 ; R/S
41       74 ; R/S
42       74 ; R/S
43       74 ; R/S
44       74 ; R/S
45       74 ; R/S
46       74 ; R/S
47       74 ; R/S
48       74 ; R/S
49       74 ; R/S
50       74 ; R/S
51       74 ; R/S
52       74 ; R/S
53       74 ; R/S
54       74 ; R/S
55       74 ; R/S
56       74 ; R/S
57       74 ; R/S
58       74 ; R/S
59       74 ; R/S
60       74 ; R/S
61       74 ; R/S
62       74 ; R/S
63       74 ; R/S
64       74 ; R/S
65       74 ; R/S
66       74 ; R/S
67       74 ; R/S
68       74 ; R/S
69       74 ; R/S
70       74 ; R/S
71       74 ; R/S
72       74 ; R/S
73       74 ; R/S
74       74 ; R/S
75       74 ; R/S
76       74 ; R/S
77       74 ; R/S
78       74 ; R/S
79       74 ; R/S
80       74 ; R/S
81       74 ; R/S
82       74 ; R/S
83       74 ; R/S
84       74 ; R/S
85       74 ; R/S
86       74 ; R/S
87       74 ; R/S
88       74 ; R/S
89       74 ; R/S
90       74 ; R/S
91       74 ; R/S
92       74 ; R/S
93       74 ; R/S
94       74 ; R/S
95       74 ; R/S
96       74 ; R/S
97       74 ; R/S
98       74 ; R/S
99       74 ; R/S
100       74 ; R/S
101       74 ; R/S
102       74 ; R/S
103       74 ; R/S
104       74 ; R/S
105       74 ; R/S
106       74 ; R/S
107       74 ; R/S
108       74 ; R/S
109       74 ; R/S
110       74 ; R/S
111       74 ; R/S
112       74 ; R/S
113       74 ; R/S
114       74 ; R/S
115       74 ; R/S
116       74 ; R/S
117       74 ; R/S
118       74 ; R/S
119       74 ; R/S
120       74 ; R/S
121       74 ; R/S
122       74 ; R/S
123       74 ; R/S
124       74 ; R/S
125       74 ; R/S
126       74 ; R/S
127       74 ; R/S
128       74 ; R/S
129       74 ; R/S
130       74 ; R/S
131       74 ; R/S
132       74 ; R/S
133       74 ; R/S
134       74 ; R/S
135       74 ; R/S
136       74 ; R/S
137       74 ; R/S
138       74 ; R/S
139       74 ; R/S
140       74 ; R/S
141       74 ; R/S
142       74 ; R/S
143       74 ; R/S
144       74 ; R/S
145       74 ; R/S
146       74 ; R/S
147       74 ; R/S
148       74 ; R/S
149       74 ; R/S
150       74 ; R/S
151       74 ; R/S
152       74 ; R/S
153       74 ; R/S
154       74 ; R/S
155       74 ; R/S
156       74 ; R/S
157       74 ; R/S
158       74 ; R/S
159       74 ; R/S
160       74 ; R/S
161       74 ; R/S
162       74 ; R/S
163       74 ; R/S
164       74 ; R/S
165       74 ; R/S
166       74 ; R/S
167       74 ; R/S
168       74 ; R/S
169       74 ; R/S
170       74 ; R/S
171       74 ; R/S
172       74 ; R/S
173       74 ; R/S
174       74 ; R/S
175       74 ; R/S
176       74 ; R/S
177       74 ; R/S
178       74 ; R/S
179       74 ; R/S
180       74 ; R/S
181       74 ; R/S
182       74 ; R/S
183       74 ; R/S
184       74 ; R/S
185 15 13 01 ; LBL 1
186       01 ; 1
187       00 ; 0
188       32 ; CHS
189    23 00 ; STO 0
190       00 ; 0
191    23 01 ; STO 1
192       01 ; 1
193    23 02 ; STO 2
194    14 74 ; PAUSE
195    24 01 ; RCL 1
196    24 02 ; RCL 2
197       51 ; +
198    14 74 ; PAUSE
                    

; Infinite Integer SQRT-go29.txt
;
; Repeatively compute, display and pause,
; the square root of integers from 1 ...
;
; BEGIN : R/S or GSB 1
; STOP : R/S
;
01 15 13 01 ; LBL 1
02       00 ; 0
03    23 01 ; STO 1
04 15 13 04 ; LBL 4
05       01 ; 1
06 23 51 01 ; STO + 1
07    24 01 ; RCL 1
08    14 74 ; PAUSE
09    14 63 ; √
10    14 74 ; PAUSE
11    13 04 ; GTO 04
12    15 12 ; RTN
13       74 ; R/S
                    

; Manhattan-go29.txt
;
; 1977 : 353 years
;            $724,492,365.57
;            4-5 minutes on the original HP-29C.
;            GO-29 does the job in zero seconds :)
; Usage:
;   353 GSB 0
;   GSB 1
;
01 15 13 00 ; LBL 0
02 14 11 02 ; FIX 2
03    23 00 ; STO 0
04       01 ; 1
05       06 ; 6
06       02 ; 2
07       04 ; 4
08    23 01 ; STO 1
09       02 ; 2
10       04 ; 4
11    23 02 ; STO 2
12    15 12 ; RTN
13 15 13 01 ; LBL 1
14       82 ; SEC
15    23 09 ; STO 9
16    24 02 ; RCL 2
17       05 ; 5
18    15 21 ; %
19 23 51 02 ; STO + 2
20       01 ; 1
21 23 51 01 ; STO + 1
22    15 23 ; DSZ
23    13 01 ; GTO 1
24       82 ; SEC
25    23 08 ; STO 8
26    24 01 ; RCL 1
27 14 11 00 ; FIX 0
28    14 74 ; PAUSE
29    24 02 ; RCL 2
30 14 11 02 ; FIX 2
31    14 74 ; PAUSE
32    24 08 ; RCL 8
33    24 09 ; RCL 9
34       41 ; -
35    15 12 ; RTN
36       74 ; R/S
                    

; Pythagorean Theorem-go29.txt
;
; Computes the hypotenuse of any right
; triangle, given the other two sides.
; The formula used is:
;
; c = √( a² + b² )
;
; Usage:
;       Y = length of one side
;       X = length of other side
;       GSB 9
;
01 15 13 09 ; LBL 9
02    15 63 ; x^2
03       21 ; Swap xy
04    15 63 ; x^2
05       51 ; +
06    14 63 ; √
07    15 12 ; RTN
08       74 ; R/S
                    

; Quadratic Roots-go29.txt
;
; Find the roots of a quadratic equation
; ax² + bx + c = 0
;
; Usage for 3x² + 2x - 1:
;   3 STO 1
;   2 STO 2
;   1 CHS STO 3
;   GSB 5 ; compute root 1  0.33
;   GSB 6 ; compute root 2 -1.00
;
01 15 13 05 ; LBL 5
02 14 11 02 ; FIX 2
03    12 08 ; GSB 8
04       51 ; +
05    24 01 ; RCL 1
06       02 ; 2
07       61 ; X
08       71 ; ÷
09    15 12 ; RTN
10 15 13 06 ; LBL 6
11    12 08 ; GSB 8
12       41 ; -
13    24 01 ; RCL 1
14       02 ; 2
15       61 ; X
16       71 ; ÷
17    15 12 ; RTN
18 15 13 08 ; LBL 8
19    24 02 ; RCL 2
20       32 ; CHS
21    24 02 ; RCL 2
22    15 63 ; x^2
23    24 01 ; RCL 1
24    24 03 ; RCL 3
25       61 ; X
26       04 ; 4
27       61 ; X
28       41 ; -
29    14 63 ; √
30    15 12 ; RTN
31       74 ; R/S
                    

; Surface Area Of Sphere-go29.txt
;
; Compute the surface area of any
; sphere using the formula:
;
; A = π d²
;
; ENTRY:
;   X = diameter of sphere.
;   GSB 0
;
; EXIT:
;   X = surface area of sphere.
;
01 15 13 00 ; LBL 0
02    15 63 ; x²
03    15 73 ; π
04       61 ; X
05    15 12 ; RTN
                    

Topics

If you attempt a calculation containing an improper operation - say, division by zero - the display will show Error. To clear, press v.

The following are improper operations:

• ÷ where X = 0
• Y^x where Y < 0 with X not an integer, or where Y = 0 with X < 0, or where X = Y = 0
• √X where X < 0
• 1/X where X = 0
• log where X <= 0
• ln where X <= 0
• sin^-1 where absolute value of X > 1
• cos^-1 where absolute value of X > 1
• STO ÷ where X = 0
• A where n <= 0
• s where n <= 0

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These are the default Settings:

• Slide Switch Gesture unavailable on macOS and Apple TV.
• Key Tap Feedback unavailable on Apple TV.
• Key Highlight Color unavailable on Apple TV.
• Background Theme unavailable on iPhones with a display smaller than 5.4 inches.
• Auto-On unavailable on Apple TV.
• Magnify Calculator disabled unless appropriate for your device.

Reminder: There are no gestures on Apple TV thus this section is not applicable, see the section GO-29 and Apple TV for details. On macOS taps/touches are pointer clicks, pans/swipes/scrolls are pointer drags.

• Shake to clear X. Not available on macOS.
• Single tap the calculator display for Copy / Paste / Paper Tape in RUN mode.
• Single tap the calculator display for Import PRGM / Share PRGM in PRGM mode.
• Double tap the calculator display to show/hide the stack, memory and paper tape views in RUN mode.
• Double tap the calculator display to show/hide the program description and listing views in PRGM mode.
• Two-finger pan for iPad to reposition the stack, program and calculator views. For macOS drag using your pointing device (if the view scrolls rather than drags, use the switch-views control as a drag point).
• Touch and hold SST or BST in RUN mode to display the next or previous step, respectively.
• Touch a program listing line to make it the current SP.
• Touch a program listing line to dismiss the keyboard while editing the program description.
• Touch and hold a program listing step for 1.0 second (long touch) to add special opcodes.
• Long touch for iPad/Mac on the program documentation window to toggle between the docked and floating views. The gripper handles resize and move the floating window: on iPad use a two-finger pan, for macOS drag using your pointing device.
• Touch switch-views control to alternate between two views.
• Swipe up and down to scroll program description, program listing and sample programs views.
• Swipe left and right to manipulate slide switches, if activated in Settings. Not available on macOS.
• Flick left on the calculator display to erase last mantissa character entered.
• Triple tap the calculator display to show/hide the Info button .

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All calculator capabilites are supported on macOS.

Topics

Most calculator capabilites are supported on Apple TV, with these notable exceptions:

• Only the Sample Programs are available for import, you enter all other programs manually, just like in 1977.
• No fancy Program editing, you do it all manually, just like in 1977.
• No fancy Program sharing, you write it down on a piece of paper, just like in 1977.
• No Copy / Paste.

Enjoy your trip in the WABAC Machine!

Focus Navigation

Use the Apple TV remote to move the screen focus left, right, up and down until the desired object is highlighted, then click. The calculator keys are arranged in a regular grid so focus navigation is easy. But to reach the Info button and either of the two switch-views controls there is a special path passing through a focus portal key that you must follow in order to move the screen focus in and out of the calculator:

• Left focus portal key q
  From the left portal key, focus left once to reach the stack and paper tape, focus left a second time to reach the Info button. Simply reverse your path to return to the calculator.

• Right focus portal key t
  From the right portal key, focus right once to reach the program, and reverse your path to return to the calculator.

You may rightly view this focus ordering as if the following objects exist in their own logically horizontal row that you can freely traverse left and right:

Stack

SST

GSB

GTO

r

t

Program

A focused, clickable object is highlighted: calculator keys with a translucent white overlay, and other objects with a gold background. When the calculator first starts the initial screen focus is on the Info button for quick access to Help and Settings, as seen in this picture. Note that the OFF-ON switch can never receive the focus because the calculator is always ON.

The Info button actually identifies with both switch-views controls, this means that the focus order is really a ring that you may circle in either direction:

As with iOS and macOS, you can view and scroll the paper tape and program listing on tvOS. Move the focus to the appropriate switch-views control , tap the control until the scrollable view of interest is visible, then pan up and down to scroll the contents. When you are finished, pan left or right to move the screen focus to the next object in the focus ring. Remember that a view is only scrollable when it has the gold focus.

Note: when a scrollable view is visible it inserts itself into the focus ring.

Topics

GO-21, GO-25 and GO-29 all provide support for hardware keyboards. You can enter digits and a decimal point into the X register by simply typing those characters, even from a numeric keypad. Use delete instead of a flick left in the display to delete the last character typed, and return instead of z to push the completed number onto the stack.

To enter an exponent of 10 for a floating point number type e instead of c. To change the sign of a mantissa or exponent type c instead of x. To perform any of the four basic arithmetic operations - + ? / on these numbers type - + * /, respectively.

So the keyboard works rather well for simple calculator operations, but it's non-trivial to do more because there are no familiar mappings between keyboard and calculator keys. However, all 30 keys and the 2 slide switches of these calculators have a keyboard equivalent, with 27 keys common to all devices and 6 keys specific to an individual model:

• ⌘? shows the Info view for Help and Settings
• keys colored red map to virtual calculator keys
• on tvOS there are even keys to mimic an Apple TV remote:

Topics

• Maximum program steps has been doubled to 198.
• Maximum number of nested subroutine calls has been doubled to 6.
• GTO + n n n extends regular GTO . n n to address program steps [100,198]. This form of GTO can, of course, still address steps [000,099].
• X, Y, Z and T registers, as well as the primary and indirect storage registers, are continuous and survive a power Off.

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OS Version Compatibilty

iOS	12.0	-	17.4
iPadOS	12.0	-	17.4
tvOS	12.0	-	17.4
macOS	10.15	-	14.4
visionOS	1.0	-	1.1

2.6 - 2024.03.10

• Fix for the T function.
• New Settings option Magnify Calculator, which creates a zoom-in effect that clips the periphery of the device body.
• Modern color picker for devices running iOS 14 or newer.
• Miscellaneous other bug fixes.
• Update for iOS 17.4, iPadOS 17.4, tvOS 17.4, macOS 14.4.

2.5 - 2022.09.12

• Support iPhone 14; cosmetic improvements for iPhones 5, 6, 7 and 8.
• Update for iOS 16, macOS 12.6, tvOS 16.

2.4 - 2022.02.22

• New Settings option Persist Program Registers - consider this a form of checkpoint/restart. When enabled:
  • On program Export device register values are saved to the program.
  • On program Import device registers are restored from the program's saved values.
• New external keyboard action: typing M invokes the multiply function, eliminating a shift.
• Nerd alert: iOS versions >= 14 and macOS versions >= 11 now use the modern PHPicker photo chooser rather than the venerable UIImagePicker.
• Minor bug fixes and improvements.
• Update for iOS 15.3.1, macOS 12.2.1, tvOS 15.3.

2.3 - 2021.01.01

• A blinking decimal point indicates battery power less than 5% (except Apple TV).
• New macOS Universal binary that runs on either Apple Silicon or Intel Macs.
• Update for iOS 14.3, macOS 11.1, tvOS 14.2.

2.2.1 - 2020.10.14

• Support iPhone 12, update for iOS 14.0.1.

2.2 - 2020.10.01

• Parser improvements when manually entering a program.
• Paper Tape Annotations now work on tvOS.
• Info enhanced when using tvOS.
• Experimental decimal math for the +, -, M+ and M- keys.
• Update for iOS 14.0, macOS 10.15.7, tvOS 14.0.

2.1 - 2020.09.19

• GO-29 SciRPN for Apple TV is now part of the universal purchase bundle.
• New background theme OS Appearance that tracks the OS's Appearance setting.
• 0⁰ produces Error rather than evaluating to 1.
• Update for iOS 13.7, macOS 10.15.6, tvOS 13.4.8.

2.0 - 2020.08.12

• GO-29 SciRPN is now a single purchase that runs on your iPod touch, iPhone, iPad and Macintosh.

1.7 - 2020.06.24

• International hardware keyboard support for iOS and macOS.
• Similar to some CuVee Software products and with permission, add ability to annotate, clear, copy, email and print the paper tape.
• The Program Run Speed slider is now non-linear, making it easier to slow the simulator so that your favorite program runs at the same speed - vintage speed - as an actual device.
• For iPad and Mac, long touch the program documentation view to transfer it to a floating window.
• New Program Branch Checks setting that monitors for an infinite loop.

1.6 - 2020.06.02

• Implement hardware keyboard support for iOS and macOS.
• In PRGM mode the macOS App allows program import and export via the new File menu items Open and Save.
• Add new program Least Mean Squares.
• Ensure conformance with Apple's 2020.06.30 App Store guidelines.
• Update for iOS 13.5.1 and macOS 10.15.5.
• Bug(s):
  1. Fix mishandling of statistical registers R.0 through R.5 during program import.

1.5 - 2020.03.19

• Add a Setting, Use iCloud Drive For Program Storage, which is set to OFF if your device is running iOS 9. This setting is used to completely disable attempts to access iCloud Drive, which is incompatible with the previous iCloud implementation used by iOS 9.
• When selecting colors on macOS use the native color picker rather than the builtin iOS color picker.
• Update Sample Program Global Optimization by Range Scan Method.

1.4 - 2020.02.02

• New program Point Load Bending Moments.
• Properly position program listing view on iPhone.
• Repair Automatic Display Switching for display formats FIX 8 and FIX 9.
• Tweak Display Engine LED segments A and F.
• Improved memory management.
• Various fixes to the keycode parser.
• Update for iOS 13.3.1 and macOS 10.15.3.

1.3 - 2020.01.15

• Add a Setting, High Visibility Display, so it's easier to view the calculator display in a very bright environment. The X register is shown in black on a white background, and each tiny LED display segment is drawn 33% larger.
• For iPhones with a 5.5 inch display or larger there is a new Background Color or Picture setting.
• PRGM mode keystrokes are now logged to the paper tape.
• New surveying Sample Program Inverse From Coordinates.
• Bug(s):
  1. CLEAR REG was overzealously also clearing the stack.
  2. Fix RCL Σ+ in PRGM mode.
  3. All 8 program conditionals (#, R, and friends) complete any numeric entry and push the value onto the stack.

1.2 - 2020.01.02

• Mac Catalyst enhancments.
• Documentation updates.
• Bug(s):
  1. Fix CLEAR PREFIX in PRGM mode.
  2. Disallow illegal key combinations.

1.1 - 2019.12.25

• Share common code with GO-21 SciRPN and GO-25 SciRPN.
• New Key Tap Feedback option Haptic Feel that uses touch feedback rather than sound to indicate a key tap, assuming your device includes the feature and that it is enabled in Settings.
• Update for iOS 13.3.
• Update for iPadOS 13.3 and macOS Catalina 10.15.2: this means that GO-29 SciRPN now runs on your friendly Macintosh computer!
• Minimum iOS version is 9.0; minimum macOS version is 10.15.
• Bug(s):
  1. Fix STO R.n and RCL R.n (1 <= n <= 5) erroneously referencing R.0.

1.0 - 2019.07.19

• Initial release.

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