The NBP Calculator

1.1.1   Portrait

The screen has the following layout when in portrait mode:

+---------------------------------------+
|                The Result Output Area |
+---------------------------------------+
|             The Expression Input Area |
+-------+-------+-------+-------+-------+
| Clear | AltKp | CMSel | DNSel | AUSel |
+-------+-------+-------+-------+-------+
|  Var  | Store | BkSpc |  Up   |  Del  |
+-------+-------+-------+-------+-------+
| f(x)  | Erase | Left  | Down  | Right |
+-------+-------+-------+-------+-------+
|                                       |
|                                       |
|     The Currently Selected Keypad     |
|                                       |
|                                       |
+---------------------------------------+

1.1.2   Landscape

The screen has the following layout when in landscape mode:

+-------------------------------------------------------+
|                                The Result Output Area |
+-------------------------------------------------------+
|                             The Expression Input Area |
+-------+-------+-------+-------------------------------+
| Clear | AltKp | CMSel |                               |
+-------+-------+-------+                               |
| DNSel |  Var  | Store |                               |
+-------+-------+-------+                               |
| AUSel | f(x)  | Erase | The Currently Selected Keypad |
+-------+-------+-------+                               |
| BkSpc |  Up   |  Del  |                               |
+-------+-------+-------+                               |
| Left  | Down  | Right |                               |
+-------+-------+-------+-------------------------------+

1.3.1   Enter Key

Typing this key completes the expression. The expression is added to the expression history, the expression line is cleared, and the final result is displayed on the result line. If there's an error then the cursor is placed at the error's location and the message is displayed on the result line.

Pressing the = key on any of the keypads performs this same action.

1.3.2   Shortcuts

the following actions can be performed by typing shortcuts on a keyboard:

1.3.3   Expression History

A history of successfully completed expressions is maintained. An expression is considered complete if there are no syntax errors within it when either the = key on any of the keypads is pressed or when the Enter key is typed.

• Pressing the Up key moves backward through the history.
• Pressing the Down key moves forward through the history.
• Long pressing the Up key moves to the earliest entry in the history.
• Long pressing the Down key moves to the most recent entry in the history.

Any history entry can be edited and recompleted, although the history entries themselves are never actually changed. Edits to an entry are lost when moving away (up or down) from it without recompleting it. Recompleting a history entry adds it as a new entry.

1.4.1   Clear

Pressing this button clears the expression line.

1.4.2   Alternate Keypad

Repeatedly pressing this button cycles through all of the keypads associated with the current calculator mode. A long press switches to the mode's primary keypad. This button is disabled if the mode only has one keypad.

1.4.3   Calculator Mode

Repeatedly pressing this button cycles through all of the calculator modes. A long press presents a list from which the desired mode can be selected. The button's label is a three-letter abbreviation for the current selection. The current selection is persistent.

The following modes are available:

DEC

Decimal (the default). This mode performs real and complex operations on IEEE 64-bit floating-point (commonly known as double) values. They consist of a 1-bit sign, an 11-bit exponent, and a 52-bit significand. Other than 0 (which is a special case), the smallest absolute value that this representation supports is 2^-1074 or approximately 5×10⁻³²⁴, and the largest absolute value that it supports is 2¹⁰²³ or approximately 1.8×10³⁰⁸. Calculations are performed with an accuracy of 15 significant digits.

This mode supports complex numbers. The imaginary component, if nonzero, is displayed as either an addition to or a subtraction from the real component. If a number doesn't have an imaginary component then only its real component is displayed. If it does have an imaginary component but doesn't have a real component then only the imaginary component is displayed. Here are some examples:

• 0
• 1
• i
• 2i
• −3
• −4i
• 5 + i
• −6 + 2i
• −7 − 3i
• 2.3×10⁴ + 5.6×10⁷i

The keypads associated wit this mode are:

• Decimal
• Function
• Conversion

HEX

Hexadecimal. This mode performs unsigned integer and bitwise operations on 64-bit values. Both input and output are in base 16 and use hexadecimal digits. Digits A through F are always displayed in uppercase but may be input in either case. A number may consist of up to 16 hexadecimal digits.

The keypads associated wit this mode are:

• Hexadecimal

1.4.4   Decimal Notation

Repeatedly pressing this button cycles through all of the decimal notations. A long press presents a list from which the desired notation can be selected. The button's label is a three-letter abbreviation for the current selection. The current selection is persistent.

The following notations are available:

FXD

Fixed (the default). If the absolute value of the number is less than 10¹² [1,000,000,000,000] and greater than or equal to 10^-3 [0.001] then it's displayed with its decimal point in its natural position. Its power of ten multiplier (e.g. ×10^x) isn't displayed (because it's 0), and digit grouping separators (e.g. 1,000) are displayed (to ease readability). If the number is an integer then the decimal point isn't displayed.

If the number is outside this range then it's considered to be too difficult to intuitively read in fixed notation, and scientific notation is used instead.

SCI

Scientific. The number is always displayed such that its absolute value is greater than or equal to 1 and less than 10. In other words, there's always exactly one digit before the decimal point. If the rest of the digits (other than the first one) are 0 then the decimal point isn't displayed. If it needs to be multiplied by a power of 10 (either positive or negative) then ×10^x is appended.

ENG

Engineering. This is identical to scientific notation except that the power of ten is always a multiple of 3 and up to 3 digits are displayed before the decimal point.

In all cases, the sign is only displayed if the number is negative. This is also true for the power of ten.

1.4.5   Angle Unit

Repeatedly pressing this button cycles through all of the trigonometric angle units. A long press presents a list from which the desired unit can be selected. The button's label is a three-letter abbreviation for the current selection. The current selection is persistent.

The following units are available:

DEG

Degrees (the default). A circle is divided into 360 degrees.

RAD

Radians. A circle is divided into 2π radians.

GON

Gradians (also known as grads or gons). A circle is divided into 400 gradians.

1.5.1   Variable

Pressing this button presents a list of the user-defined variables followed by the predefined variables. Each line contains the name and current value of a variable. For a predefined variable, it also contains its description.

Selecting a variable from this list enters its name into the expression line. The following actions are also available:

Cancel

Dismiss the list without taking any action.

1.5.2   Store

Pressing this button presents a list of the user-defined variables. Each line contains the name and current value of a variable.

Selecting a variable from this list assigns the value currently shown on the result line to it. The following actions are also available:

Cancel

Dismiss the dialog without taking any action.

New

Present a dialog for entering the name of a new variable. This dialog doesn't allow an existing variable to be overwritten. It offers the following actions:

Cancel

Dismiss the dialog without taking any action.

Store

Assign the value currently shown on the result line to to the new variable. This action is disabled when the name field is empty and when it contains the name of an existing variable.

Variables can also be created or updated via the = operator within an expression. For example:

• x = 1
• x = y = 2
• x = 3 + y = 4 + z = 5

To clarify: the last example sets z to 5, y to 9, and x to 12.

1.5.3   Erase

Pressing this button presents a list of the user-defined variables. Each line contains the name and current value of a variable.

Selecting a variable from this list removes its definition. The following actions are also available:

Cancel

Dismiss the dialog without taking any action.

A long press presents the same list in a way that allows several variable definitions to be removed at once. It offers the following additional actions:

Erase

Remove the definitions of all the variables that have been selected.

1.5.4   f(x)

Pressing this button presents a list of the predefined functions. Each line contains the name and description of a function.

Selecting a function from this list enters its name, followed by an open bracket, into the expression line. The following actions are also available:

Cancel

Dismiss the dialog without taking any action.

1.6.1   Left

Pressing this button moves the cursor one character to the left. A long press moves the cursor all the way to the left. This button is disabled when the cursor is to the left of the first character.

1.6.2   Right

Pressing this button moves the cursor one character to the right. A long press moves the cursor all the way to the right. This button is disabled when the cursor is to the right of the last character.

1.6.3   Backspace

Pressing this button deletes the character immediately to the left of the cursor. A long press deletes all of the characters to the left of the cursor. This button is disabled when the cursor is to the left of the first character.

1.6.4   Delete

Pressing this button deletes the character immediately to the right of the cursor. A long press deletes all of the characters to the right of the cursor. This button is disabled when the cursor is to the right of the last character.

1.6.5   Up

Pressing this button moves to the previous entry in the expression history. A long press moves to the earliest (oldest) entry. This button is disabled when on the earliest entry.

1.6.6   Down

Pressing this button moves to the next entry in the expression history. A long press moves to the latest (most recent) entry. This button is disabled when on the latest entry.

1.7.1   Decimal

This is the primary keypad for the Decimal calculator mode. It has the following layout:

Most of these keys enter whatever their label says into the expression line. The exceptions are:

• The = key completes the expression. It's equivalent to typing the Enter key.
• The x^y key enters ^ (the actual exponentiation operator).
• The x⋅10^y key enters ×10^. It's for multiplying a number by a power of ten.

The " and ' keys are for entering a number in the degrees"minutes'seconds format. Each of these components ("minutes and 'seconds) is optional. If specified, it's value must be an integer that's greater than or equal to 0 and less then 60. If omitted, it's value is assumed to be 0. If any of these components is specified then a decimal point may not be used.

1.7.2   Function

This is the second keypad for the Decimal calculator mode. It has the following layout:

Each of these keys enters its function's name, followed by an open bracket [(], into the expression line. The exceptions are e and pi, which don't enter the open bracket because they're variables.

1.7.3   Conversion

This is the third keypad for the Decimal calculator mode. It has the following layout:

Each four-key row is a separate key group. This allows five different unit conversions to be configured. Each of them, as shown above, defaults to a common US-to-International unit conversion.

The first three keys configure the conversion:

Type

This key presents a list from which the desired unit type (e.g. length, area, volume) can be selected.

From

This key presents a list from which the unit that the supplied value is in can be selected. The list only contains units belonging to the currently configured type.

To

This key presents a list from which the unit that the supplied value is to be converted to can be selected. The list only contains units belonging to the currently configured type.

The rightmost key is for actually performing the currently configured unit conversion. It's label shows what that conversion is in the form from2to (e.g. mi2km). This is the name of the predefined function that performs the conversion. Just like the keys on the Function keypad, pressing this key enters the name of this function, followed by an open bracket [(], into the expression line.

Any of the unit conversion functions can be directly typed into the expression line. Because there are so many, none of them is included within the list presented by pressing the f(x) button.

The most recently configured conversion for each unit type for each key group is persistent.

1.7.4   Hexadecimal

This is the primary keypad for the Hexadecimal calculator mode. It has the following layout:

Each of these keys enters whatever its label says into the expression line. The 0 through 9 and A through F keys are the 16 hexadecimal digits. The rest of the keys are as follows:

2.2.1   Infix

2.2.2   Prefix

2.2.3   Postfix

2.4.1   Unit Conversion Functions

3.1.1   Predefined Variables

3.2.1   Predefined Functions

3.3.1   Angle

3.3.2   Area

3.3.3   Energy

3.3.4   Force

3.3.5   Length

3.3.6   Mass

3.3.7   Power

3.3.8   Pressure

3.3.9   Speed

3.3.10   Temperature

3.3.11   Time

3.3.12   Volume

3.4.1   For Positive Powers of Ten

3.4.2   For Negative Powers of Ten

3.4.3   For Positive Powers of Two