Keyboard

Overview

The Keyboard is the standard NCS/e text input peripheral.

Unlike most peripherals, the Keyboard does not provide its own NCL verbs. The Keyboard sends key events directly to the kernel, which stores them in an input buffer. Other compatible input devices may also generate key events for this buffer.

Programs access buffered keyboard input using the SYS.KEY and SYS.AKEY system verbs.

Keys are buffered in the order they are received. Reading a key removes the oldest key from the buffer.

This buffering model is specific to keyboard input. Other input peripherals, such as joysticks, may be accessed directly through their own EXT interfaces.

Input buffer

Keyboard input is buffered by the kernel until it is read by a program.

Programs may read the buffer in one of two ways:

  • SYS.KEY reads the oldest available key without waiting.
  • SYS.AKEY reads the oldest available key, waiting if necessary.

Both verbs consume the same input buffer.

If several keys have already been entered, repeated reads return them in the order they were received.

Reading keys

SYS.KEY — Read Key

SYS.KEY <dst>

Removes the oldest key from the keyboard input buffer and stores it in the destination register.

If the buffer is empty, an empty string is returned immediately.

Operands

Position Name Type Description
1 dst String register Destination for the key.

Modified registers

Register Description
dst Oldest buffered key, or "" if no key is available.

Examples

-- Read the next available key.
SYS.KEY s0

The empty string may be used to determine whether input was available:

SYS.KEY s0
BSEQ $noInput s0 ""

-- Process the key here.

$noInput

Notes

  • SYS.KEY never waits for input.
  • Reading a key removes it from the input buffer.
  • If the buffer is empty, "" is returned.
  • Buffered keys are consumed in the order they were received.

SYS.AKEY — Await Key

SYS.AKEY <dst>

Removes the oldest key from the keyboard input buffer and stores it in the destination register.

If the buffer is empty, program execution waits until a key becomes available.

Operands

Position Name Type Description
1 dst String register Destination for the key.

Modified registers

Register Description
dst Oldest buffered key.

Examples

-- Wait for the next key.
SYS.AKEY s0

A program may use SYS.AKEY when it cannot continue until the user provides input:

D.TXT "Press any key..."
D.BLT

SYS.AKEY s0

It may also be used for a simple interactive input loop:

$input
SYS.AKEY s0
D.TXT s0
D.BLT
JUMP $input

Notes

  • If a key is already buffered, it is returned immediately.
  • If the buffer is empty, execution waits until a key is received.
  • Reading a key removes it from the input buffer.
  • Buffered keys are consumed in the order they were received.

Polling and awaiting input

SYS.KEY and SYS.AKEY differ only in their behavior when no input is available.

Verb Key available Buffer empty
SYS.KEY Returns the oldest key. Returns "" immediately.
SYS.AKEY Returns the oldest key. Waits until a key is available.

SYS.KEY is useful when a program needs to check for input while continuing to perform other work:

SYS.KEY s0
BSEQ $continue s0 ""

-- Handle input.

$continue

SYS.AKEY is useful when the program cannot proceed until input is received:

D.TXT "CONTINUE? [Y/N]"
D.BLT

SYS.AKEY s0

Because both verbs operate on the same kernel buffer, they may also be mixed within a program as needed.

Keyboard layouts

The standard Keyboard translates physical key presses into string values according to its keyboard layout and active modifiers.

Printable keys normally produce characters, while special keys may produce named values such as LEFT, HOME, or F1.

The modifier keys have the following roles:

Modifier Purpose
Shift Selects the shifted key value.
Alt Selects the alternate character or AltGr value.
Shift+Alt Selects the shifted alternate value.
Ctrl Selects the key's function value, where defined.

The labels Alt and Ctrl are used by the standard Keyboard hardware. Functionally, Alt behaves as an AltGr modifier, while Ctrl selects additional function-key mappings.

Caps toggles alphabetic capitalization. While Caps is active, unshifted letters produce uppercase characters and Shift produces lowercase characters. Caps does not affect numbers or symbols and remains active until pressed again.

Special keyboard behavior

Compatible keyboards may perform processing before sending input to the kernel. This behavior depends on the keyboard and its active layout.

Dead keys may wait for another key before producing a value. For example, a dead accent key followed by a letter may produce a single accented character rather than two separate key events.

Macros may generate a sequence of key values from a single key press. These values are added to the input buffer in order and are read normally using SYS.KEY or SYS.AKEY.

System controls

The standard Keyboard provides dedicated ABORT and RESET controls. These controls act directly on the system and do not produce values in the keyboard input buffer.

Control Effect
ABORT Immediately aborts the currently running program and returns control to the shell.
RESET Power-cycles the NCS/e, equivalent to switching the computer off and back on.
Ctrl+C Invokes the same ABORT function as the dedicated ABORT control.

Standard layouts

The standard Keyboard is available with several keyboard layouts. Each layout defines the complete mapping of physical keys, including modifier combinations, function keys, navigation keys, and the numeric keypad.

Expand a layout below to view its complete key map.

A value marked dead is a dead key. Dead keys modify the following character instead of being entered immediately. Dead-key combinations are shared by all layouts and are listed under Dead key combinations.

US English

Layout
Key Normal Shift Alt Alt+Shift Ctrl
Esc ESC ESC ESC ESC ESC
F1 F1 F1 F1 F1 F1
F2 F2 F2 F2 F2 F2
F3 F3 F3 F3 F3 F3
F4 F4 F4 F4 F4 F4
F5 F5 F5 F5 F5 F5
F6 F6 F6 F6 F6 F6
F7 F7 F7 F7 F7 F7
F8 F8 F8 F8 F8 F8
F9 F9 F9 F9 F9 F9
F10 F10 F10 F10 F10 F10
F11 F11 F11 F11 F11 F11
F12 F12 F12 F12 F12 F12
` ` ~ — — ESC
Enter ENTER ENTER LF RI CR
1 1 ! — — F1
2 2 @ — — F2
3 3 # — — F3
4 4 $ — — F4
5 5 % — — F5
6 6 ^ — — F6
7 7 & — — F7
8 8 * — — F8
9 9 ( — — F9
0 0 ) — — F10
- - _ — — F11
= = + — — F12
Backspace BS BS BS BS DEL
A a A — — —
B b B — — —
C c C — — ABORT
D d D — — —
E e E — — —
F f F — — —
G g G — — BEL
H h H — — BS
I i I — — TAB
J j J — — LF
K k K — — VT
L l L — — FF
M m M — — CR
N n N — — —
O o O — — —
P p P — — —
Q q Q — — —
R r R — — —
S s S — — —
T t T — — —
U u U — — —
V v V — — —
W w W — — —
X x X — — —
Y y Y — — —
Z z Z — — —
Space         —
[ [ { — — —
] ] } — — —
; ; : — — —
' ' " — — —
\ \ | — — —
, , < — — —
. . > — — —
/ / ? — — —
Tab TAB BACKTAB TAB BACKTAB —
Numpad 1 1 1 1 1 END
Numpad 2 2 2 2 2 DOWN
Numpad 3 3 3 3 3 PGDN
Numpad 4 4 4 4 4 LEFT
Numpad 5 5 5 5 5 —
Numpad 6 6 6 6 6 RIGHT
Numpad 7 7 7 7 7 HOME
Numpad 8 8 8 8 8 UP
Numpad 9 9 9 9 9 PGUP
Numpad 0 0 0 0 0 —
Numpad . . . . . DEL
Numpad / / / / / —
Numpad * * * * * —
Numpad - - - - - —
Numpad + + + + + —
Numpad Enter ENTER ENTER LF RI CR
Left LEFT LEFT LEFT LEFT HOME
Down DOWN DOWN DOWN DOWN PGDN
Up UP UP UP UP PGUP
Right RIGHT RIGHT RIGHT RIGHT END
Home HOME HOME HOME HOME —
End END END END END —
Page Up PGUP PGUP PGUP PGUP —
Page Down PGDN PGDN PGDN PGDN —

Canadian French

Layout
Key Normal Shift Alt Alt+Shift Ctrl
Esc ESC ESC ESC ESC ESC
F1 F1 F1 F1 F1 F1
F2 F2 F2 F2 F2 F2
F3 F3 F3 F3 F3 F3
F4 F4 F4 F4 F4 F4
F5 F5 F5 F5 F5 F5
F6 F6 F6 F6 F6 F6
F7 F7 F7 F7 F7 F7
F8 F8 F8 F8 F8 F8
F9 F9 F9 F9 F9 F9
F10 F10 F10 F10 F10 F10
F11 F11 F11 F11 F11 F11
F12 F12 F12 F12 F12 F12
# # | \ — ESC
Enter ENTER ENTER LF RI CR
1 1 ! ± — F1
2 2 " @ — F2
3 3 / £ — F3
4 4 $ ¢ — F4
5 5 % ¤ — F5
6 6 ? ¬ — F6
7 7 & ¦ — F7
8 8 * ² — F8
9 9 ( ³ — F9
0 0 ) ¼ — F10
- - _ ½ — F11
= = + ¾ — F12
Backspace BS BS BS BS DEL
A a A — — —
B b B — — —
C c C — — ABORT
D d D — — —
E e E € — —
F f F — — —
G g G — — BEL
H h H — — BS
I i I — — TAB
J j J — — LF
K k K — — VT
L l L — — FF
M m M µ — CR
N n N — — —
O o O § — —
P p P — —
Q q Q — — —
R r R — — —
S s S — — —
T t T — — —
U u U — — —
V v V — — —
W w W — — —
X x X — — —
Y y Y — — —
Z z Z — — —
Space         —
^ ^ (dead) ^ (dead) [ — —
¸ ¸ (dead) ¨ (dead) ] — —
; ; : ~ — —
` ` (dead) ` (dead) { — —
< < > } — —
, , ' ¯ — —
. . . ­ — —
é é É ´ (dead) — —
« « » ° — —
Tab TAB BACKTAB TAB BACKTAB —
Numpad 1 1 1 1 1 END
Numpad 2 2 2 2 2 DOWN
Numpad 3 3 3 3 3 PGDN
Numpad 4 4 4 4 4 LEFT
Numpad 5 5 5 5 5 —
Numpad 6 6 6 6 6 RIGHT
Numpad 7 7 7 7 7 HOME
Numpad 8 8 8 8 8 UP
Numpad 9 9 9 9 9 PGUP
Numpad 0 0 0 0 0 —
Numpad . . . . . DEL
Numpad / / / / / —
Numpad * * * * * —
Numpad - - - - - —
Numpad + + + + + —
Numpad Enter ENTER ENTER LF RI CR
Left LEFT LEFT LEFT LEFT HOME
Down DOWN DOWN DOWN DOWN PGDN
Up UP UP UP UP PGUP
Right RIGHT RIGHT RIGHT RIGHT END
Home HOME HOME HOME HOME —
End END END END END —
Page Up PGUP PGUP PGUP PGUP —
Page Down PGDN PGDN PGDN PGDN —

French

Layout

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Dead key combinations

Dead keys combine with the following character to produce an accented or modified character. Dead-key processing is independent of the selected keyboard layout: any layout capable of producing a supported dead key can use the combinations below.

Combinations
Dead key Characters Results
Grave ` A E I O U À È Ì Ò Ù
a e i o u à è ì ò ù
Acute ´ A E I O U Y Á É Í Ó Ú Ý
a e i o u y á é í ó ú ý
Circumflex ^ A E I O U Â Ê Î Ô Û
a e i o u â ê î ô û
Tilde ~ A N O Ã Ñ Õ
a n o ã ñ õ
Diaeresis ¨ A E I O U Y Ä Ë Ï Ö Ü Ÿ
a e i o u y ä ë ï ö ü ÿ
Ring ° A U Å Ů
a u å ů
Macron ¯ A E I O U Ā Ē Ī Ō Ū
a e i o u ā ē ī ō ū
Cedilla ¸ C Ç
c ç
Caron ˇ C D E N R S T Z Č Ď Ě Ň Ř Š Ť Ž
c d e n r s t z č ď ě ň ř š ť ž
Breve ˘ A E G I O U Ă Ĕ Ğ Ĭ Ŏ Ŭ
a e g i o u ă ĕ ğ ĭ ŏ ŭ
Ogonek ˛ A E I O U Ą Ę Į Ǫ Ų
a e i o u ą ę į ǫ ų
Dot above ˙ B C E G I M Z Ḃ Ċ Ė Ġ İ Ṁ Ż
b c e g i m z ḃ ċ ė ġ i ṁ ż
Double acute ˝ O U Ő Ű
o u ő ű