Arnitech controller: the TOD set at boot, and a jump table at $FF00

A new option, ARNITECH_CONTROLLER, on in the mc64 configuration only.
IOINIT starts timer A with CIA #1's TOD on 50 Hz, the mc64's mains, and
if the Arnitech controller's signature "ARNI" is at $DE80, latches its
clock and copies its real time into the TOD, hours first and tenths
last, flipping bit 7 of an hour of 12 first, since the CIA flips it
back when 12 is written. Without the signature the TOD is left alone.

The Arnitech jump table at $FF00: "ARNI", version $01, two entries, and
JMPs from $FF06: $FF06 finds the first Card slot holding a Card of the
type in A (carry clear, the slot in A, its Card window's low byte in
X; carry set if none or no controller), $FF09 sets the TOD as IOINIT
does. $FF48-$FF80 stay clear. The code is in new files under
src/kernal/arnitech; other configurations build as before.

src/kernal/arnitech/ff00.arnitech_jumptable.s

@@ -0,0 +1,40 @@
+;; #LAYOUT# STD *        #TAKE
+;; #LAYOUT# *   *        #IGNORE
+
+;
+; The Arnitech jump table (mc64 only): thin wrappers over the Arnitech controller's registers
+; (arnitech's ADR 0023), at fixed addresses. Software finds it by reading "ARNI" at $FF00 with
+; the KERNAL banked in; on any other KERNAL it uses the registers themselves, which work the same.
+; Entries are only ever added, after the last, with the version and count raised; $FF48-$FF80
+; stay clear, for the stock IRQ entry, CINT, and the KERNAL revision byte.
+;
+; $FF00-$FF03  "ARNI"
+; $FF04        version of the table, $01
+; $FF05        number of entries
+;
+; $FF06  ARNI_FINDCARD - finds the first Card slot holding a Card of a given type
+;        In:  A = the Card's type ($01 Redstone Card, $02 Internet Card; $00 finds an empty slot)
+;        Out: carry clear if found: A = the slot (0-5), X = the low byte of its Card window
+;             ($DEA0 + 16 * slot, so LDA $DE00,X reads the window's first byte);
+;             carry set if no slot holds one, or no controller answers (a Cartridge switched it off)
+;        Y is kept; A and X are not, when none is found
+;
+; $FF09  ARNI_SETTOD - sets CIA1's TOD from the controller's real time, as IOINIT does at boot
+;        In:  nothing; CIA1's CRB bit 7 must be 0, or the time goes into the TOD alarm
+;        Out: carry clear if set: the TOD on 50 Hz (CIA1 CRA bit 7) and started at the time the
+;             controller's clock latch read; carry set if no controller answers, with the TOD
+;             untouched but on 50 Hz all the same
+;        A and X are not kept, Y is
+;
+
+!ifdef CONFIG_ARNITECH_CONTROLLER {
+
+arnitech_jumptable:
+
+	!byte $41, $52, $4E, $49           ; "ARNI"
+	!byte $01                          ; version
+	!byte $02                          ; entries
+
+	jmp arnitech_find_card             ; $FF06
+	jmp arnitech_set_tod               ; $FF09
+}