Reconstruct SSV 22 source code

[larsbrinkhoff]

Reconstruct SSV 22 source code from the IMTRAN'ed binary.

According to records (see #1001), SSV 22 is from 1974-04-05. (Roughly contemporary with MAZE, #236, #1330.) The closest relative seems to be the ML file IMLAC; SSV 52 dated 1973-01-11. This file may have been edited to run on a PDS-4 (#1598), but the differences are minor. Other files which can inform the reconstruction are SSVMSE (#1398), SST 21 (#1503), and STV 21.

[larsbrinkhoff]

Also reverse engineer some documentation for SSV 22.

This is from the KEYDIS table. Some key codes for now.

Key	Function
XMIT	Line transmit
Control ↓	Delete down
↓	Move cursor down
→	Right arrow
Control →	Delete right
Control ↑	Delete up
↑	Move cursor up
Control →	Delete left
→	Move curor left
Control Shift TAB	Reload (jump to bootstrap)
Control TAB	Reinitialize SSV
Shift TAB	Set TTY mode
LF	LF
Shift LF	Down
FF	14
Shift FF	Toggle TTY/EDIT mode
CR	CR
Shift CR	Reverse CRLF
Shift PAGE SMIT	Slow page xmit
Control PAGE XMIT	Page xmit, clearing screen
HOME	Home
Shift HOME	Home up
Shift 230	Clear current line
230	Toggle cursor twitchery
Control 230	Clear screen
Shift BRK	Toggle auto repeat
BRK	Toggle upper/lower case
232	Delete character to the right of cursor
ESC	Esc, Altmode
Control Shift ESC	Start program at 10000
234	Delete current line
235	Insert comment
Shift 235	Toggle margin line
236	37
Shift 236	Delete character to the right of cursor
237	11
377	DEL
Shift 377	Delete character to the right of cursor
Control Shift 377	Clear screen

[larsbrinkhoff]

Cursor etc codes. From TTYDIS table:

Code	Function
001	Dispatch on next character
007	Dong, ring bell
010	Backspace
011	Tab
012	Line feed, more cursor down and to the left margin
013	Move cursor down
014	Clear screen
015	Carriage return, move cursor to left margin
016 x y	Move cursor to x, y
017	Move cursor left
020	Delete from cursor to end of screen
021	Delete from cursor to end of line
022	Clear screen
023	Delete current line
024	Move cursor to start of screen
025	More cursor to end of screen
030	Delete character
031	Move cursor right
032	Move cursor up
033	Insert altmode
035 a b c d	ARDS set point
036 a b c d	ARDS long vector
037 a b	ARDS short vector

[larsbrinkhoff]

001 dispatch character, next character:

Code	Function
001	Jump to 40, load program from bootstrap
002	Insert TECO cursor
003	Move to end of screen
004	Same as 003
005	Same as 003
006	Jump to 10000, for overlaid program
007	Edit mode
010	TTY mode

[larsbrinkhoff]

@jdersch, this is source code for SSV 22.

[larsbrinkhoff]

The assembled file is an exact binary match against @tuban's SSV file. MIDAS 324 is used rather than the latest version, because the latter will insert extra zeroes.