lst off
	rel
	xc
	xc

	mx %11
	use vt.equ

	ext scroll_down
	ext recalc_cursor,recalc_cursor_x,recalc_cursor_y

vt100
	mx %11
	and #$7f
	cmp #' '
	bcs :notctrl
	asl
	tax
	jmp (:ctrl_table,x)
:notctrl
	ldx state
	jmp (:state_table,x)



:state_table
	ext vt52_esc,vt52_dca
	ext vt100_esc,vt100_csi,vt100_csi_2
	ext vt100_esc_pound,vt100_esc_lparen,vt100_esc_rparen
	ext vt100_esc_bad,vt100_csi_bad
	ext draw_char

	dw draw_char
	dw vt52_esc
	dw vt52_dca
	dw draw_char
	dw vt100_esc
	dw vt100_csi
	dw vt100_csi_2
	dw vt100_esc_pound
	dw vt100_esc_lparen
	dw vt100_esc_rparen
	dw vt100_esc_bad
	dw vt100_csi_bad


:ctrl_table
	dw ctrl_00,ctrl_01,ctrl_02,ctrl_03
	dw ctrl_04,ctrl_05,ctrl_06,ctrl_07
	dw ctrl_08,ctrl_09,ctrl_0a,ctrl_0b
	dw ctrl_0c,ctrl_0d,ctrl_0e,ctrl_0f
	dw ctrl_10,ctrl_11,ctrl_12,ctrl_13
	dw ctrl_14,ctrl_15,ctrl_16,ctrl_17
	dw ctrl_18,ctrl_19,ctrl_1a,ctrl_1b
	dw ctrl_1c,ctrl_1d,ctrl_1e,ctrl_1f



ctrl_00
ctrl_01
ctrl_02
ctrl_03
ctrl_04
ctrl_05 ; answer ENQ
ctrl_06
ctrl_0e ; G1 character set
ctrl_0f ; G0 character set
ctrl_10
ctrl_11 ; XON
ctrl_12
ctrl_13 ; XOFF
ctrl_14
ctrl_15
ctrl_16
ctrl_17
ctrl_19
ctrl_1c
ctrl_1d
ctrl_1e
ctrl_1f
	rts


ctrl_07 ; ring the bell.
	rts

ctrl_1b ; escape -
* vt100 - aborts current escape sequence and starts a new one.
* vt52 - esc esc aborts and starts new 
* vt50 - esc esc aborts
	lda DECANM
	bne :vt52
	lda #st_vt100_esc
	sta state
	rts

:vt52
	lda #st_vt52_esc
	sta state
	rts

ctrl_18
ctrl_1a
* vt100 - abort current escape sequence
* and display error character.
* TODO - display error character (mouse text)
	lda DECANM
	bne :vt52
	lda #st_vt100
	sta state
	rts

:vt52
	lda #st_vt52
	sta state
	rts

ctrl_08 ; back space
	lda x
	beq :rts
	and #$7f
	dec
	sta x
	jmp recalc_cursor_x
:rts

ctrl_09 ; tab
* vt100 has adjustable tabs.
	ext next_tab_stop
	ldx x
	bmi :rts
	jsr next_tab_stop
	stx x
	jmp recalc_cursor_x
:rts rts

ctrl_0a ; line feed - cursor down w/ scroll
ctrl_0b ; vertical tab
ctrl_0c ; form feed.

* if LNM is active, equivalent to CR, LF

	bit #LNM
	bpl :lf
	stz x
	jsr recalc_cursor_x

:lf
	lda y
	cmp #DECBM
	blt :simple

*	lda #" " ; needs to factor in reverse video
*	sta cursor_saved_char
	jmp scroll_down
* if LNM mode, need to update cursor as well.

:simple
	inc y
	jmp recalc_cursor_y

ctrl_0d ; carriage return - cursor to column 0.
	stz x
	jmp recalc_cursor_x


	sav vt100.main.L