more work on MEGA65 keyboard support

src/kernal/keyboard_m65/mega65_scnkey.s

@@ -69,21 +69,116 @@ m65_scnkey_shflag_next:
 	; Scan the keyboard matrix stored in memory to determine which keys were pressed
 	;
 
+	ldx #$02
+@1:
+	lda M65_KB_PRESSED, x
+	sta M65_KB_PRESSED_OLD, x
+	dex
+	bpl @1
+
+	jsr m65_scnkey_init_pressed
+
 	lda M65_KB_COLSUM
+	beq m65_scnkey_no_key              ; branch if no key was pressed   XXX try joystick
+
+	ldx #$08
+
+	; FALLTROUGH
+
+m65_scnkey_loop_1:
+
+	lda M65_KB_COLSCAN, x
+	pha
+	ldy #$FF
+
+	; FALLTROUGH
+
+m65_scnkey_loop_2:
+
+	iny
+	pla
+	beq m65_scnkey_next_1
+	asl
+	pha
+	bcc m65_scnkey_loop_2
+
+	; Found a pressed key - add it to the list
+
+	lda M65_KB_PRESSED+2
+	bpl m65_scnkey_jam                 ; branch if too many keys pressed
+	lda M65_KB_PRESSED+1
+	sta M65_KB_PRESSED+2
+	lda M65_KB_PRESSED+0
+	sta M65_KB_PRESSED+1
+
+	sty M65_KB_PRESSED+0
+	txa
+	asl
+	asl
+	asl
+	clc
+	adc M65_KB_PRESSED+0
+	sta M65_KB_PRESSED+0
+
+	bra m65_scnkey_loop_2
+
+m65_scnkey_next_1:
+
+	dex
+	bpl m65_scnkey_loop_1
+
+	;
+	; Analyze currently and previously pressed keys
+	;
+
+	; XXX add proper implementation
+	ldx M65_KB_PRESSED+0
+
+	;
+	; Convert the key coordinates to key code
+	;
+
+	; XXX add proper implementation
+	ldy __kb_matrix_normal, x
 	beq m65_scnkey_no_key
 
+m65_scnkey_output_key:
+
+	;
+	; Output selected key to the keyboard buffer
+	;
+
+	; Check if we have free space in the keyboard buffer
+
+	lda NDX
+	cmp XMAX
+	+bcs scnkey_buffer_full
+
+	; Put the key into the keyboard buffer
+
+	tya
+	ldy NDX
+	sta KEYD, y
+	inc NDX
+
+	rts
+
+
 	; XXX
 
 
-
-
 	
 
-m65_scnkey_no_key:
 
 
+m65_scnkey_jam:
 
 	; XXX
 
+	jmp m65_scnkey_init_pressed
+
+m65_scnkey_no_key:
+
+	; XXX
 
 	rts

src/kernal/keyboard_m65/mega65_scnkey_init_pressed.s

@@ -0,0 +1,12 @@
+;; #LAYOUT# M65 KERNAL_0 #TAKE
+;; #LAYOUT# *   *        #IGNORE
+
+
+m65_scnkey_init_pressed:
+
+	lda #$FF
+	sta M65_KB_PRESSED+0
+	sta M65_KB_PRESSED+1
+	sta M65_KB_PRESSED+2
+
+	rts