keyboard: add some sample keyboard code

keyboard/Makefile

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+include ../Makefile.inc
+
+DOS33 = ../utils/dos33fs-utils/dos33
+DOS33_RAW = ../utils/dos33fs-utils/dos33_raw
+TOKENIZE = ../utils/asoft_basic-utils/tokenize_asoft
+LINKER_SCRIPTS = ../linker_scripts
+EMPTY_DISK = ../empty_disk
+
+all:	keyboard.dsk
+
+keyboard.dsk:	HELLO KEYBOARD
+	cp $(EMPTY_DISK)/empty.dsk keyboard.dsk
+	$(DOS33) -y keyboard.dsk SAVE A HELLO
+	$(DOS33) -y keyboard.dsk BSAVE -a 0xc00 KEYBOARD
+
+###
+
+HELLO:	hello.bas
+	$(TOKENIZE) < hello.bas > HELLO
+
+###
+
+KEYBOARD:	keyboard.o
+	ld65 -o KEYBOARD keyboard.o -C $(LINKER_SCRIPTS)/apple2_c00.inc
+
+keyboard.o:	keyboard.s
+	ca65 -o keyboard.o keyboard.s -l keyboard.lst
+
+###
+
+clean:	
+	rm -f *~ *.o *.lst HELLO KEYBOARD
+

keyboard/hello.bas

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+5 HOME
+10 PRINT CHR$(4)"BRUN KEYBOARD"
+
+
+

keyboard/keyboard.s

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+; HARDWARE LOCATIONS
+
+KEYPRESS        =       $C000
+KEYRESET        =       $C010
+KEYSTROBE	=	$C010
+
+; on original Apple II/II+
+;	read KEYPRESS
+;		if bit 7 set, means key was pressed, value in lower 7 bits
+;	access KEYSTROBE to clear value and allow another keypress to happen
+; on Apple IIe
+;	can read KEYSTROBE.  bit 7 is "any key is down"
+
+
+; test keyboard
+
+keyboard:
+
+	ldy	#0
+
+keyboard_loop:
+	lda	KEYPRESS
+	bpl	keyboard_loop
+
+	ora	#$80
+	sta	$400,Y
+	iny
+	bit	KEYRESET
+
+	jmp	keyboard_loop
+