feat(arnitech): the Terminal Card is a Blade's screen and keyboard

With ARNITECH_BLADE the screen editor, the keyboard matrix scan, and the VIC-II
set-up are left out, and devices 3 and 0 are the Terminal Card the Arnitech
controller finds by its type, $04. CHROUT writes each byte to its Output, or
to its Literal while quote or insert mode is on, keeping QTSW and INSRT as the
screen editor does. CHRIN marks where input starts, echoes the keys typed, and
on RETURN has the Card take the logical line under the cursor and reads it
back. SCNKEY moves the Card's keys into the keyboard buffer up to XMAX, UDTIM
sets STKEY from its RUN/STOP, SCREEN answers 80x25, PLOT moves and reads its
cursor, and CINT resets it and puts the native-mode vectors in place. With no
Terminal Card, bytes printed go nowhere and no key comes.

src/kernal/iostack/e50a.plot.s

@@ -26,12 +26,39 @@ plot_set:
 	sty PNTR
 	stx TBLX
 
+!ifndef CONFIG_ARNITECH_BLADE {
+
 	jsr screen_calculate_pointers
 
+} else {
+
+	; On a Blade the cursor is the Terminal Card's, which clamps it to the 80x25 screen;
+	; PNTR and TBLX keep the last place set or read, which is all there is without a Card
+
+	jsr terminal_find
+	bcs plot_get_kept
+	lda PNTR
+	sta TERMINAL_COLUMN, x
+	lda TBLX
+	sta TERMINAL_ROW, x
+}
+
 	; FALLTROUGH to save one byte on RTS
 
 plot_get:
 
+!ifdef CONFIG_ARNITECH_BLADE {
+
+	jsr terminal_find
+	bcs plot_get_kept
+	lda TERMINAL_COLUMN, x
+	sta PNTR
+	lda TERMINAL_ROW, x
+	sta TBLX
+
+plot_get_kept:
+}
+
 	ldy PNTR
 	ldx TBLX
 	rts