; Testing input.
;
; Writen in Sux assembly by
; mr b0nk 500 <b0nk@b0nk.xyz>


; Initalize some variables.
.org $1000
scr_row:
	.byte $0
scr_col:
	.byte $0
a:
	.word $0
b:
	.word $0
c:
	.word $0
d:
	.word $0
string:
	.byte "Please, type something.\n"
string2:
	.byte "You typed, "
end:
	.byte $0

; Input buffer.
.org $0000
buffer:

; Main program
.org $8000
reset:
	cps
	ldx.w #$FFFF
	txs
	ldy #$0
clr_buf:
	lda #$0
	cpy.w #$1000
	beq start
	sta buffer, y
	iny
	jmp clr_buf

start:
	ldx.w #$0	; Reset x.
	ldy.w #$0	; Reset y.
	jmp print

rset_a:
	lda #$10
delay:
	beq read
	dec
	jmp delay
sleep:
	lda end
	bne spin	; Are we done with getting input?
read:
	lda $C000	; Get control register.
	beq rset_a	; Loop until we get a character.
	lda #$0
	sta $C000
	jmp getchar	; We got a key.

print:
	lda string, x	; Get character at offset x.
	beq rset_a	; Did we find a null terminator?
	sta $C001	; Print character.
	inx		; Increment offset.
	cmp #$A
	beq inc_row
	inc scr_col
	jmp print
inc_row:
	inc scr_row
	lda #$0
	sta scr_col
	jmp print	; Keep printing more characters.

getchar:
	lda $C002	; Get typed character.
	cmp #$1B
	beq esc
	cmp #$A
	beq nl		; Did the user type a newline?
	cmp #$8
	beq bs		; Did the user type a backspace?
	cmp #$7F
	beq bs		; Did the user type a backspace?
echo:
	sta a
	ldx scr_col
	cpx #$79
	bne echo_print
linewrap:
	inc scr_row
	ldx #$0
	stx scr_col
	jsr update_pos
echo_print:
	lda a
	sta $C001	; Echo typed character.
	inc scr_col	; Increment the cursor's x coordinate.
	sta buffer, y	; Store typed character into the input buffer.
	iny		; Increment the buffer offset.
	jmp rset_a	; Start getting user input.

esc:
	lda $C000	; Skip the '['.
	lda $C000	; Get the next character.
	beq read	; We have an error, so discard it, and go back to getting user input.
	lda $C002	; Get the escape code.
	sta c		; Store the escape code, until we need it.
	jsr isup	; Check if the user pressed up.
	lda d
	cmp #$0
	bne esc_end
	jsr isdown	; Check if the user pressed down.
	lda d
	cmp #$0
	bne esc_end
	lda #$0
	jsr isleft	; Check if the user pressed left.
	lda d
	cmp #$0
	bne esc_end
	jsr isright	; Check if the user pressed right.
esc_end:
	lda #$0
	sta d
	jmp rset_a	; Go back to getting user input.

isup:
	lda scr_row	; Is the cursor at the top of the screen?
	beq isup_done	; Yes, so return.
	lda c		; No, so load the escape code back into the accumulator.
	cmp #$41	; Did the user press the up arrow key?
	beq up		; Yes, so move the cursor up.
isup_done:
	rts		; End of isup.

isdown:
	lda scr_row	; Start checking the y coordinate of the cursor.
	cmp #$17	; Is the cursor at the bottom of the screen?
	beq isdown_done	; Yes, so return.
	lda c		; No, so load the escape code back into the accumulator.
	cmp #$42	; Did the user press the down arrow key?
	beq down	; Yes, so move the cursor down.
isdown_done:
	rts		; End of isdown.

isright:
	lda scr_col	; Start checking the x coordinate of the cursor.
	cmp #$4F	; Is the cursor at the far right of the screen?
	beq isright_end	; Yes, so return.
	lda c		; No, so load the escape code back into the accumulator.
	cmp #$43	; Did the user press the right arrow key?
	beq right	; Yes, so move the cursor right.
isright_end:
	rts		; End of isright.

isleft:
	lda scr_col	; Is the cursor at the far left of the screen?
	beq isleft_done	; Yes, so return.
	lda c		; No, so load the escape code back into the accumulator.
	cmp #$44	; Did the user press the left arrow key?
	beq left	; Yes, so move the cursor left.
isleft_done:
	rts		; End of isleft.

up:
	dec scr_row
	jsr update_pos
	lda #$1
	sta d
	jmp isup_done
down:
	inc scr_row
	jsr update_pos
	lda #$1
	sta d
	jmp isdown_done
right:
	inc scr_col
	jsr update_pos
	jmp isright_end
left:
	dec scr_col
	jsr update_pos
	lda #$1
	sta d
	jmp isleft_done

update_pos:
	lda #$1B	; Print an escape character
	sta $C001	; to the screen.
	lda #$5B	; Print '['
	sta $C001	; to the screen, and start the escape sequence.
	jsr getrow	; Start printing the row number to the screen.
	jsr getcol	; Start printing the column number to the screen.
	lda #$48	; Print 'H'
	sta $C001	; to the screen.
	rts		; End of update_pos.
getrow:
	lda scr_row	; Get the cursor's y coordinate.
	div #$A		; Divide A by 10.
	adc #$30	; Convert it to ascii, and
	sta $C001	; print to the screen.
	tba		; Get the remainder.
	adc #$30	; Convert it to ascii, and
	sta $C001	; print to the screen.
	rts		; End of getrow.
getcol:
	lda #$3B	; Print ';'
	sta $C001	; to the screen.
	lda scr_col	; Get the cursor's x coordinate.
	div #$A		; Divide A by 10.
	adc #$30	; Convert it to ascii, and
	sta $C001	; print to the screen.
	tba		; Get the remainder.
	adc #$30	; Convert it to ascii, and
	sta $C001	; print to the screen.
	rts		; End of getrow.

uint_to_bcd:
	div #$A		; Divide A by 10.
	lsl #$4		; Shift the result left by 4 bits.
	sta a		; Store the result for later.
	tba		; Get the remainder.
	sta b		; Store the remainder for later.
	lda a		; Get the result.
	ora b		; Or the result, with the remainder.
	rts		; We've converted the value to BCD, so return.

nl:
	lda #$A
	sta $C001
	inc scr_row
	lda #$0		; Replace newline with a null terminator.
	sta buffer, y	; Store said terminator into the input buffer.
	sta scr_col
	ldy.w #$0	; Reset y, to print the result.
	jmp result

back:
	sta $C001	; Print backspace.
	lda #$0		; Put a null terminator, in place of the backspace.
	sta buffer, y	; Place it into the input buffer.
	dey		; Decrement buffer offset.
	dec scr_col
	jmp read	; Get next character.

bs:
	cpy #$0		; Are we at the start of the buffer?
	beq rset_a	; We are, so do not store the backspace into the buffer.
	jmp back	; We are not, so add the backspace to the buffer.

result:
	ldx scr_col
	cpx #$79
	bne result_print
linewrap:
	inc scr_row
	ldx #$0
	stx scr_col
	jsr update_pos
result_print:
	lda string2, y
	beq rset_y	; Reset y, if we hit the null terminator.
	sta $C001	; Print 'You have typed, '
	inc scr_col	; Increment the cursor's x coordinate.
	iny		; Increment offset.
	jmp result	; Keep printing.


rset_y:
	ldy.w #$0
	jmp print_buf	; Print the input buffer.

print_buf:
	ldx scr_col
	cpx #$79
	bne buf_print
linewrap:
	inc scr_row
	ldx #$0
	stx scr_col
	jsr update_pos
buf_print:
	lda buffer, y	; Get a character from the input buffer.
	beq spin	; Are we done with printing the buffer?
	sta $C001	; Print said character.
	inc scr_col	; Increment the cursor's x coordinate.
	iny
	jmp print_buf	; Keep printing the buffer.

spin:
	nop
	nop
	nop
	jmp spin

.org $FFC0
.qword reset

.org $FF50
.qword spin
.qword spin
.qword spin
.qword spin
.qword spin
.qword spin
.qword spin

.org $FFA0
.qword irq_routine
.org $8000
viewmem
.org $8100
viewmem
.org $8200
viewmem
;q
done