; Prog8 definitions for the Text I/O and Screen routines for the Commodore-64
; All routines work with Screencode character encoding, except `print`, `chrout` and `input_chars`,
; these work with PETSCII encoding instead.

%import syslib
%import conv
%import shared_cbm_textio_functions

txt {

    %option no_symbol_prefixing, ignore_unused

const ubyte DEFAULT_WIDTH = 40
const ubyte DEFAULT_HEIGHT = 25

romsub $FFD2 = chrout(ubyte character @ A)    ; for consistency. You can also use cbm.CHROUT directly ofcourse. Note: takes a PETSCII encoded character.

sub  clear_screen() {
    chrout(147)
}

sub  cls() {
    chrout(147)
}

sub home() {
    chrout(19)
}

sub nl() {
    chrout('\n')
}

sub spc() {
    chrout(' ')
}

sub bell() {
    ; beep
    c64.MVOL = 11
    c64.AD1 = %00110111
    c64.SR1 = %00000000
    c64.FREQ1 = 8500
    c64.CR1 = %00010000
    c64.CR1 = %00010001
}

asmsub column(ubyte col @A) clobbers(A, X, Y) {
    ; ---- set the cursor on the given column (starting with 0) on the current line
    %asm {{
        pha
        sec
        jsr  cbm.PLOT
        pla
        tay
        clc
        jmp  cbm.PLOT
    }}
}


asmsub get_column() -> ubyte @Y {
    %asm {{
        sec
        jmp cbm.PLOT
    }}
}

asmsub row(ubyte rownum @A) clobbers(A, X, Y) {
    ; ---- set the cursor on the given row (starting with 0) on the current line
    %asm {{
        pha
        sec
        jsr  cbm.PLOT
        pla
        tax
        clc
        jmp  cbm.PLOT
    }}
}

asmsub get_row() -> ubyte @X {
    %asm {{
        sec
        jmp cbm.PLOT
    }}
}

sub get_cursor(uword colptr, uword rowptr) {
    %asm {{
        sec
        jsr cbm.PLOT
        tya
        ldy #$00
        sta (colptr),y
        txa
        sta (rowptr),y
    }}
}


asmsub  fill_screen (ubyte character @ A, ubyte color @ Y) clobbers(A)  {
	; ---- fill the character screen with the given fill character and character color.
	;      (assumes screen and color matrix are at their default addresses)

	%asm {{
		pha
		tya
		jsr  clear_screencolors
		pla
		jsr  clear_screenchars
		rts
        }}

}

asmsub  clear_screenchars (ubyte character @ A) clobbers(Y)  {
	; ---- clear the character screen with the given fill character (leaves colors)
	;      (assumes screen matrix is at the default address)
	%asm {{
		ldy  #250
-		sta  cbm.Screen+250*0-1,y
		sta  cbm.Screen+250*1-1,y
		sta  cbm.Screen+250*2-1,y
		sta  cbm.Screen+250*3-1,y
		dey
		bne  -
		rts
        }}
}

asmsub  clear_screencolors (ubyte color @ A) clobbers(Y)  {
	; ---- clear the character screen colors with the given color (leaves characters).
	;      (assumes color matrix is at the default address)
	%asm {{
		ldy  #250
-		sta  cbm.Colors+250*0-1,y
		sta  cbm.Colors+250*1-1,y
		sta  cbm.Colors+250*2-1,y
		sta  cbm.Colors+250*3-1,y
		dey
		bne  -
		rts
        }}
}

sub color (ubyte txtcol) {
    cbm.COLOR = txtcol
}

sub lowercase() {
    c64.VMCSB |= 2
}

sub uppercase() {
    c64.VMCSB &= ~2
}

asmsub  scroll_left  (bool alsocolors @ Pc) clobbers(A, X, Y)  {
	; ---- scroll the whole screen 1 character to the left
	;      contents of the rightmost column are unchanged, you should clear/refill this yourself
	;      Carry flag determines if screen color data must be scrolled too

	%asm {{
		bcc _scroll_screen

+               ; scroll the screen and the color memory
		ldx  #0
		ldy  #38
-
        .for row=0, row<=24, row+=1
            lda  cbm.Screen + 40*row + 1,x
            sta  cbm.Screen + 40*row + 0,x
            lda  cbm.Colors + 40*row + 1,x
            sta  cbm.Colors + 40*row + 0,x
        .next
		inx
		dey
		bpl  -
		rts

_scroll_screen  ; scroll only the screen memory
		ldx  #0
		ldy  #38
-
        .for row=0, row<=24, row+=1
            lda  cbm.Screen + 40*row + 1,x
            sta  cbm.Screen + 40*row + 0,x
        .next
		inx
		dey
		bpl  -

		rts
	}}
}

asmsub  scroll_right  (bool alsocolors @ Pc) clobbers(A,X)  {
	; ---- scroll the whole screen 1 character to the right
	;      contents of the leftmost column are unchanged, you should clear/refill this yourself
	;      Carry flag determines if screen color data must be scrolled too
	%asm {{
		bcc  _scroll_screen

+               ; scroll the screen and the color memory
		ldx  #38
-
        .for row=0, row<=24, row+=1
            lda  cbm.Screen + 40*row + 0,x
            sta  cbm.Screen + 40*row + 1,x
            lda  cbm.Colors + 40*row + 0,x
            sta  cbm.Colors + 40*row + 1,x
        .next
		dex
		bpl  -
		rts

_scroll_screen  ; scroll only the screen memory
		ldx  #38
-
        .for row=0, row<=24, row+=1
            lda  cbm.Screen + 40*row + 0,x
            sta  cbm.Screen + 40*row + 1,x
        .next
		dex
		bpl  -

		rts
	}}
}

asmsub  scroll_up  (bool alsocolors @ Pc) clobbers(A,X)  {
	; ---- scroll the whole screen 1 character up
	;      contents of the bottom row are unchanged, you should refill/clear this yourself
	;      Carry flag determines if screen color data must be scrolled too
	%asm {{
		bcc  _scroll_screen

+               ; scroll the screen and the color memory
		ldx #39
-
        .for row=1, row<=24, row+=1
            lda  cbm.Screen + 40*row,x
            sta  cbm.Screen + 40*(row-1),x
            lda  cbm.Colors + 40*row,x
            sta  cbm.Colors + 40*(row-1),x
        .next
		dex
		bpl  -
		rts

_scroll_screen  ; scroll only the screen memory
		ldx #39
-
        .for row=1, row<=24, row+=1
            lda  cbm.Screen + 40*row,x
            sta  cbm.Screen + 40*(row-1),x
        .next
		dex
		bpl  -

		rts
	}}
}

asmsub  scroll_down  (bool alsocolors @ Pc) clobbers(A,X)  {
	; ---- scroll the whole screen 1 character down
	;      contents of the top row are unchanged, you should refill/clear this yourself
	;      Carry flag determines if screen color data must be scrolled too
	%asm {{
		bcc  _scroll_screen

+               ; scroll the screen and the color memory
		ldx #39
-
        .for row=23, row>=0, row-=1
            lda  cbm.Colors + 40*row,x
            sta  cbm.Colors + 40*(row+1),x
            lda  cbm.Screen + 40*row,x
            sta  cbm.Screen + 40*(row+1),x
        .next
		dex
		bpl  -
		rts

_scroll_screen  ; scroll only the screen memory
		ldx #39
-
        .for row=23, row>=0, row-=1
            lda  cbm.Screen + 40*row,x
            sta  cbm.Screen + 40*(row+1),x
        .next
		dex
		bpl  -

		rts
	}}
}

asmsub  setchr  (ubyte col @X, ubyte row @Y, ubyte character @A) clobbers(A, Y)  {
	; ---- sets the character in the screen matrix at the given position
	%asm {{
		pha
		tya
		asl  a
		tay
		lda  _screenrows+1,y
		sta  _mod+2
		txa
		clc
		adc  _screenrows,y
		sta  _mod+1
		bcc  +
		inc  _mod+2
+		pla
_mod		sta  $ffff		; modified
		rts

_screenrows	.word  cbm.Screen + range(0, 1000, 40)
	}}
}

asmsub  getchr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
	; ---- get the character in the screen matrix at the given location
	%asm  {{
		pha
		tya
		asl  a
		tay
		lda  setchr._screenrows+1,y
		sta  _mod+2
		pla
		clc
		adc  setchr._screenrows,y
		sta  _mod+1
		bcc  _mod
		inc  _mod+2
_mod		lda  $ffff		; modified
		rts
	}}
}

asmsub  setclr  (ubyte col @X, ubyte row @Y, ubyte color @A) clobbers(A, Y)  {
	; ---- set the color in A on the screen matrix at the given position
	%asm {{
		pha
		tya
		asl  a
		tay
		lda  _colorrows+1,y
		sta  _mod+2
		txa
		clc
		adc  _colorrows,y
		sta  _mod+1
		bcc  +
		inc  _mod+2
+		pla
_mod		sta  $ffff		; modified
		rts

_colorrows	.word  $d800 + range(0, 1000, 40)
	}}
}

asmsub  getclr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
	; ---- get the color in the screen color matrix at the given location
	%asm  {{
		pha
		tya
		asl  a
		tay
		lda  setclr._colorrows+1,y
		sta  _mod+2
		pla
		clc
		adc  setclr._colorrows,y
		sta  _mod+1
		bcc  _mod
		inc  _mod+2
_mod		lda  $ffff		; modified
		rts
	}}
}

sub  setcc  (ubyte col, ubyte row, ubyte character, ubyte charcolor)  {
	; ---- set char+color at the given position on the screen
	%asm {{
		lda  row
		asl  a
		tay
		lda  setchr._screenrows+1,y
		sta  _charmod+2
		adc  #$d4
		sta  _colormod+2
		lda  setchr._screenrows,y
		clc
		adc  col
		sta  _charmod+1
		sta  _colormod+1
		bcc  +
		inc  _charmod+2
		inc  _colormod+2
+		lda  character
_charmod	sta  $ffff		; modified
		lda  charcolor
_colormod	sta  $ffff		; modified
		rts
	}}
}

asmsub  plot  (ubyte col @ Y, ubyte row @ X) {
	%asm  {{
		clc
		jmp  cbm.PLOT
	}}
}

asmsub width() clobbers(X,Y) -> ubyte @A {
    ; -- returns the text screen width (number of columns)
    %asm {{
        jsr  cbm.SCREEN
        txa
        rts
    }}
}

asmsub height() clobbers(X, Y) -> ubyte @A {
    ; -- returns the text screen height (number of rows)
    %asm {{
        jsr  cbm.SCREEN
        tya
        rts
    }}
}

asmsub waitkey() -> ubyte @A {
    %asm {{
-       jsr cbm.GETIN
        beq -
        rts
    }}
}
}