demo: move things to functions, no net win?

demos/demosplash2022/draw_letter.s

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+	;========================
+	; draw letter
+	;========================
+	; so inefficient
+	; letter to draw in INL:INH
+
+draw_letter:
+
+	ldy	#$FF			; iterator
+letter_loop:
+
+
+hplot:
+	; setup X value
+
+	iny
+
+	jsr	get_x			; get adjusted x-coord in A
+
+	tax				; put in X
+
+	; setup Y value
+
+	jsr	get_y
+
+	ldy	#0			; set top of X value (FIXME)
+
+	jsr     HPLOT0  	        ; plot at (Y,X), (A)
+
+	ldy	SAVE_Y			; restore pointer
+
+	iny
+
+hplot_to:
+
+	; get X value
+
+	jsr	get_x			; get adjusted x-coord in A
+
+	pha				; save for later
+
+	lda	#0			; wrap if > 256
+	adc	#0
+	tax
+
+	; get Y value
+
+	jsr	get_y
+
+	tay				; put into Y
+
+	pla				; restore X value
+
+	jsr	HGLIN			; line to (X,A),(Y)
+
+	ldy	SAVE_Y
+
+	iny
+
+	; see if at end of line or of whole thing
+
+	lda	(INL),Y			; get next value
+
+	bmi	letter_done		; if negative, we are done
+
+	cmp	#$7F
+	beq	hplot
+	bne	hplot_to
+
+letter_done:
+	rts
+
+
+	;================
+	; get next X co-ord
+	; multipy by 2
+	; increment y
+get_x:
+	lda	(INL),Y			; get X value
+	asl				; need to multiply by 2
+	clc
+	adc	LETTER_X
+
+	iny
+
+	rts
+
+	;================
+	; get next Y co-ord
+	; increment y
+	; save to SAVE_Y
+
+get_y:
+	sty	SAVE_Y			; save Y value on stack for later
+
+	lda	(INL),Y			; get Y value
+	clc
+	adc	LETTER_Y
+
+	rts
+