MOS API ‐ Virtual Keyboard - breakintoprogram/agon-docs GitHub Wiki

This feature was introduced from MOS 1.04 RC2 and VDP 1.04 RC2

The Virtual Keyboard was set up primarily for BBC BASIC to emulate INKEY(-n), where n is one of the numbers in the virtual keycode list in this article. It allows for the user to detect multiple key presses from within a BASIC program. Where possible, the numbers match those in the Acorn standard for compatibility with typed-in programs.

Example: Check for cursor keys being pressed in BASIC

   10 CLS
   20 PRINT TAB(0,0);
   30 PRINT "UP ";INKEY(-58);" "
   40 PRINT "DOWN ";INKEY(-42);" "
   50 PRINT "LEFT ";INKEY(-26);" "
   60 PRINT "RIGHT ";INKEY(-122);" "
   70 GOTO 20

Via MOS

It is possible to read this keymap directly; it is stored in a bit-packed 16-byte table, where each bit position corresponds to a value in the table, where bit 0 is keycode 1 and bit 127 is keycode 128.

Example: Reading a virtual keycode in ADL mode (24-bit):

	MOSCALL	mos_getkbmap
	BIT	1, (IX + 3)		; Test bit 25 of the virtual keymap (keycode 26 = LEFT)

Example: Reading a virtual keycode in Z80 mode (16-bit):

	MOSCALL	mos_getkbmap
	BIT.LIL	1, (IX + 15)		; Test bit 121 of the virtual keymap (keycode 122 = RIGHT)

Virtual Keycodes

Code	Key	Code	Key	Code	Key	Code	Key
-1	Shift	-17	Q	-33	F0/Print	-49	1
-2	Ctrl	-18	3	-34	W	-50	2
-3	Alt	-19	4	-35	E	-51	D
-4	Left Shift	-20	5	-36	T	-52	R
-5	Left Ctrl	-21	F4	-37	7	-53	6
-6	Left Alt	-22	8	-38	I	-54	U
-7	Right Shift	-23	F7	-39	9	-55	O
-8	Right Ctrl	-24	-	-40	0	-56	P
-9	Right Alt	-25	^	-41	_	-57	[
-10	Mouse Select	-26	Left	-42	Down	-58	Up
-11	Mouse Menu	-27	Keypad 6	-43	Keypad 8	-59	Keypad +
-12	Mouse Adjust	-28	Keypad 7	-44	Keypad 9	-60	Keypad -
-13		-29	F11	-45	Break	-61	Keypad Enter
-14		-30	F12	-46	` ~	-62	Insert
-15		-31	F10	-47		-63	Home
-16		-32	Scroll Lock	-48	Backspace	-64	PgUp
-65	Caps Lock	-81	Shift Lock	-97	TAB	-113	Escape
-66	A	-82	S	-98	Z	-114	F1
-67	X	-83	C	-99	Space	-115	F2
-68	F	-84	G	-100	V	-116	F3
-69	Y	-85	H	-101	B	-117	F5
-70	J	-86	N	-102	M	-118	F6
-71	K	-87	L	-103	, <	-119	F8
-72	@	-88	;	-104	. >	-120	F9
-73	:	-89	]	-105	/ ?	-121
-74	Return	-90	Delete	-106	Copy/End	-122	Right
-75	Keypad /	-91		-107	Keypad 0	-123	Keypad 4
-76	Keypad Del	-92	Keypad *	-108	Keypad 1	-124	Keypad 5
-77	Keypad .	-93	Keypad ,	-109	Keypad 3	-125	Keypad 2
-78	Num Lock	-94	Keypad = +	-110		-126	WinLeft
-79	PgDn	-95		-111		-127	WinRight
-80		-96	_	-112		-128	WinMenu