ADDS Regent 25 emulation

[davidrg]

This is an initial attempt at emulating ADDS Regent terminals. At this time the implementation will be based on documented behaviour only as I have no access to physical examples of these terminals to check actual behaviour. Where the documentation is vague on detail, features may be left out until I can get someone with a real terminal to confirm actual behaviour.

Regent 25

Documentation: On Bitsavers

Implemented:

• Basic escape sequences and control characters
• Basic Keyboard map
• Numeric key pad map: numeric keys as function keys. Perhaps use "set terminal keypad-mode" to toggle this keymap.
• Documentation updated

Not implemented:

• DC2/DC4 AUX port on/off: documentation is unclear on what the expected behaviour should be
• International character sets: no documentation available on what these are
• No Regent-specific monitor mode is enabled - instead use CKWs existing debug mode (set terminal debug on)
• Audible key feedback - instead use a mechanical keyboard

Known implementation differences vs a real terminal:

• Both types of keyboard lock (ADDS Consul 580 and Normal) are supported at all times (the real terminal has a switch to select between the two)

Relevant settings:

• auto scroll on/off - set terminal autoscroll
• auto line feed - set terminal newline-mode on
• cursor: set terminal cursor block/underline blink/noblink