Splitting Open Firmware screen into two windows
Tinkerer Atlarge
Open Firmware. My initial aim was to figure out what "vectored
variables" were all about. Initial attempts to re-target global
"my-vector" resulted in lock-ups, so I ended up varying its targets
instead. The obfuscation layer that now buries it resulted from my
attempts to make it work with display resolutions different from my own.
The only practical use I can think for it as it stands is for keeping
the contents of one window on screen by swapping to the other window and
continue working from there.
\ "swapper.of" 9-Dec-2010 -- intended as demonstration only.
\
\ divides Open Firmware framebuffer text-screen vertically into two
\ full-width borderless windows. Written & tested under dflt fb8 pkg.
\
\ Specify new (2nd) window's vertical start-locations and bg color
\ 0 CONSTANT window1 ( literal 0 used below for top screen line )
032 CONSTANT window2 ( example value used for this demo )
window2 3 #lines 2- between not ( minimum 2 lines for smaller window)
abort" window2 off screen or not big enough: edit 'window2' in src"
( commands employing 'exit?' need > 2 lines to work correctly )
0b ( cyan ) CONSTANT window2-color
\ Derive non-overlapping window dimensions ("lines" = lines of text)
window2 1- CONSTANT title-bar
alias window1-#lines title-bar
1 CONSTANT title-bar-#lines
#lines window1-#lines title-bar-#lines + - CONSTANT window2-#lines
\ save original text-screen's state-values
0 to column#
create save-vector 44 allot
my-vector save-vector 44 move
\ This next section is not needed by all versions of Macintosh Open
\ Firmware. If demo works, try it again with this section removed
%r25 %r28 DO \ search fcode table
i @ 10 - @ 0a6d6f76 ( 0a"mov" ) = IF \ quick-find probable match
i @ 0f - " move-lines" comp \ verify match
0= IF ( found )
" move-lines" i @ (is-user-word) LEAVE \ dictionary alias
THEN
THEN
i %r25 4- = IF
." Installation failed: essential resource not located"
\ compile will terminate with "move-lines not found"
THEN
4 +LOOP
%r25 %r28 DO \ search fcode table
i @ 10 - @ 0b657261 ( 0b"era" ) = IF \ quick-find probable match
i @ 0f - " erase-lines" comp \ verify match
0= IF ( found )
" erase-lines" i @ (is-user-word) LEAVE \ dictionary alias
THEN
THEN
i %r25 4- = IF
." Installation failed: essential resource not located"
\ compile will terminate with "erase-lines not found"
THEN
4 +LOOP
\ scroll full-screen text up to window1's bottom line if overlap
cr \ delete this line if junk appends to every line (some vers only)
line# window1-#lines >= IF
line# title-bar 1- - 0 window1-#lines move-lines
window1-#lines 1- to line#
THEN
\ Clear space for new window using new window's background color
background-color \ save on stack
window2-color to background-color
window2 window2-#lines erase-lines
to background-color \ restore
\
\ reduce original full-screen terminal emulation to window1 dimensions
( needs to be done here as some vers of rom erase all below cursor )
window1-#lines to #lines
window1-#lines 1- line# min to line#
#lines to lines/page
\ copy a my-vector member value to same-named offset at another vector
( Note reversal of direction: vector is vectored via offset )
: via ( n vector -- ) \ usage: <n> <vector> via vectored-value !
' 8 + @ +
;
\ Clone & modify fb state variables for temp one-line title-bar window
create title-bar-vector 44 allot
my-vector title-bar-vector 44 move
title-bar char-height * window-top + title-bar-vector via window-top !
title-bar-#lines title-bar-vector via #lines !
title-bar-#lines 1- title-bar-vector via line# !
\ Clone & modify a set of fb state variables for 2nd (bottom) window
create alt-vector 44 allot
my-vector alt-vector 44 move
window2-color alt-vector via background-color !
window2 char-height * window-top + alt-vector via window-top !
window2-#lines alt-vector via #lines !
create temp-vector 44 allot
: other-window \ toggle i/o between the two potentially active windows
my-vector temp-vector 44 move
alt-vector my-vector 44 move
temp-vector alt-vector 44 move
#lines to lines/page
;
: kill-windows
['] window-top 8 + @ \ get vectored value's offset
dup my-vector + @ swap save-vector + @ <> IF
other-window \ ensure current window = window1
THEN
line#
save-vector my-vector 44 move \ restore full-screen window
to line#
line# 1+ #lines 1- line# - erase-lines \ clear screen below cursor
cr ( this cr will clear scrn below cursor for some versions of rom)
#lines to lines/page
;
\ To clean up thoroughly, also 'forget window2' at prompt. However
\ that would also forget any extra words defined via either window.
\ Title Bar treated as a window for initialization purposes only
my-vector temp-vector 44 move
title-bar-vector my-vector 44 move
\ User instructions (text for adding to title bar):
" 'other-window' toggles between windows, 'kill-windows' ends demo "
\ extra cosmetics give title bar the appearance of a window tab:
background-color -rot \ save on stack
#columns 0f - over - spaces \ right-justify text+rhs margin
window2-color to background-color type \ print text in window2 color
to background-color 0f 1- spaces \ render rhs margin in window1 color
temp-vector my-vector 44 move
\ Final init 2nd window: home its cursor without displaying prompt
other-window \ window2
0 to line#
other-window \ exit to original prompt in window1
\
\ user can now swap between & issue forth commands from either window
\