;Ram vars
Cursor_X equ $00FF0000		;Ram for X_position 
Cursor_Y equ $00FF0000+1	;Ram for Y position

;Video Ports
VDP_data equ $C00000	;VDP data port R/W word or long access only
VDP_ctrl equ $C00004	;VDP control port word or longword writes only

;Header for fusion 
;	
;	dc.l $FFFFFE00		;Mem 4 STAK PTR
;	dc.l ProgramStart	;start of prog
;	dc.l 62,InterruptHandler	;62*InterruptHandler
;	
;	ds.b 256,0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; 					Traps
	DC.L	$FFFFFE00		;SP register value
	DC.L	ProgramStart	;Start of Program Code
	DS.L	7,IntReturn		; bus err,addr err,illegal inst,divzero,CHK,TRAPV,priv viol
	DC.L	IntReturn		; TRACE
	DC.L	IntReturn		; Line A (1010) emulator
	DC.L	IntReturn		; Line F (1111) emulator
	DS.L	4,IntReturn		; Reserverd /Coprocessor/Format err/ Uninit Interrupt
	DS.L	8,IntReturn		; Reserved
	DC.L	IntReturn		; spurious interrupt
	DC.L	IntReturn		; IRQ level 1
	DC.L	IntReturn		; IRQ level 2 EXT
	DC.L	IntReturn		; IRQ level 3
	DC.L	IntReturn		; IRQ level 4 Hsync
	DC.L	IntReturn		; IRQ level 5
	DC.L	IntReturn		; IRQ level 6 Vsync
	DC.L	IntReturn		; IRQ level 7 
	DS.L	16,IntReturn	; TRAPs
	DS.L	16,IntReturn	; Misc (FP/MMU)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;					Header
	DC.B	"SEGA GENESIS    "	;System Name
	DC.B	"(C)TAILS"			;Copyright
 	DC.B	"2026.Oct"			;Date            
	DC.B	"TailsCo                                         " ; Cart Name
	DC.B	"SweetDreams                                     " ; Cart Name (Alt)
	DC.B	"GM TAILS001-00"	;TT NNNNNNNN-RR T=Type (GM=Game) N=game Num  R=Revision
	DC.W	$0000				;16-bit Checksum (Address $000200+)
	DC.B	"J               "	;Control Data (J=3button K=Keyboard 6=6button C=cdrom)
	DC.L	$00000000			;ROM Start
	DC.L	$003FFFFF			;ROM Length
	DC.L	$00FF0000,$00FFFFFF	;RAM start/end (fixed)
	DC.B	"            "		;External RAM Data
	DC.B	"            "		;Modem Data
	DC.B	"                                        " ;MEMO
	DC.B	"JUE             "	;Regions Allowed

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;					Generic Interrupt Handler
IntReturn:
	rte
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;					Program Start
ProgramStart:
	;initialize TMSS (TradeMark Security System)
	move.b ($A10001),D0		;A10001 test the hardware version
	and.b #$0F,D0
	beq	NoTmss				;branch if no TMSS chip
	move.l #'SEGA',($A14000);A14000 disable TMSS 
NoTmss:

;;;ProgramStart:

;Set up screen
	lea VDPSettings,a5	;init screen registers
	move.l #19,d1	;number of settings
	
	move.w (VDP_ctrl),d0	;C00004 read vdp status (intrrupt acknowledge?)
	move.l #$00008000,d5	;VDP Reg command ($8rvv) R=Reg V=new Value .. had to add an$ after the#
	
NextInitByte:
	move.b (a5)+,d5		;get next video control byte
	move.w d5,(VDP_ctrl)	;c00004 senda write register command to VDP. 8RVV - R=Reg V=Value
	add.w #$0100,d5		;point to next VDP register
	dbra d1,NextInitByte	;loop for rest of block

	;Define palette (%----BBB-GGG-RRR-)
	move.l #$C0000000,VDP_ctrl	;Color 0
	move.w #%0000011011001110,VDP_data
	move.l #$C0020000,VDP_ctrl	;Color 1
	move.w #%0000111111111111,VDP_data
	
	;Setup Font
	lea Font,a1	; Font Address in ROM
	move.l #26*8*4,d6	;our font contains 26 8 line 4 bytes per line
	
	move.l #$44200000,(VDP_ctrl)	;start writes to address $0420
					;patterns in vram
NextFont:
	move.b (a1)+,d0		;Get byte from font
	moveq.l #7,d5		;bit count (eight bits)
	clr.l d1		;Reset buildup byte
					
Font_NextBit:	;1 color per nibble = 4 bytes

	rol.l #3,d1	;shift buildup 3 bytes left
	roxl.b #1,d0	;shift a bit from the 1bpp font into the pattern
	roxl.l #1,d1	;shift bit into BuildUp
	dbra d5,Font_NextBit	;Next bit from font
	
	move.l d1,(VDP_data)	;vvrite next long of char to VDP_data (one line)
	dbra d6,NextFont	;loop untill done
	
	clr.w Cursor_X		;clear cursor xy
	move.w #$8144,(VDP_ctrl)	;turn on screen
	
	lea Message,a3		;string to show
	jsr PrintString		;print string to screen
	
	jmp *			;infinite loop
	
PrintChar:	;show d0 to screen
	and.l #%11011111,d0	;convert to uppercase
	sub.l #32,d0		;no characters in our font below 32
PrintCharAlt:
	move.l #$40000003,d5	;top 4 = write, bottom $3=CXXX range (tile map)
	clr.l d4
	
	move.b (Cursor_Y),d4
	move.l #8+8+7,d1
	rol.l d1,d4
	add.l d4,d5		;add 4------3
	
	move.b (Cursor_X),d4
	move.l #8+8+1,d1
	rol.l d1,d4
	add.l d4,d5		;add 4------3
	
	move.l d5,(VDP_ctrl)	;C00004 write next character to VDP
	move.w d0,(VDP_data)	;C00000 store next word of name data
	
	addq.b #1,(Cursor_X)	;inc Xposition
	rts

PrintString:
	move.b (a3)+,d0		;read a character from A3
	cmp.b #255,d0	
	beq PrintString_Done	;return on 255
	jsr PrintChar		;print the character
	bra PrintString
PrintString_Done
	rts
	
	
		
InterruptHandler:		;Basic interrupt handler
	rte
	
Font:
	dc.b $18,$3C,$66,$66,$7E,$66,$24,$00 ;A
	dc.b $3C,$66,$66,$7C,$66,$66,$3C,$00 ;B
	dc.b $38,$7C,$C0,$C0,$C0,$7C,$38,$00 ;C
	dc.b $3C,$64,$66,$66,$66,$64,$38,$00 ;D
	dc.b $3C,$7E,$60,$78,$60,$7E,$3C,$00 ;E
	dc.b $38,$7C,$60,$78,$60,$60,$20,$00 ;F
	dc.b $3C,$66,$C0,$C0,$CC,$66,$3C,$00 ;G
	dc.b $24,$66,$66,$7E,$66,$66,$24,$00 ;H
	dc.b $10,$18,$18,$18,$18,$18,$08,$00 ;I
	dc.b $08,$0C,$0C,$0C,$4C,$FC,$78,$00 ;J
	dc.b $24,$66,$6C,$78,$6C,$66,$24,$00 ;K
	dc.b $20,$60,$60,$60,$60,$7E,$3E,$00 ;L
	dc.b $44,$EE,$FE,$D6,$D6,$D6,$44,$00 ;M
	dc.b $44,$E6,$F6,$DE,$CE,$C6,$44,$00 ;N
	dc.b $38,$6C,$C6,$C6,$C6,$6C,$38,$00 ;O
	dc.b $38,$6C,$64,$7C,$60,$60,$20,$00 ;P
	dc.b $38,$6C,$C6,$C6,$CA,$74,$3A,$00 ;Q
	dc.b $3C,$66,$66,$7C,$6C,$66,$26,$00 ;R
	dc.b $3C,$7E,$60,$3C,$06,$7E,$3C,$00 ;S
	dc.b $3C,$7E,$18,$18,$18,$18,$08,$00 ;T
	dc.b $24,$66,$66,$66,$66,$66,$3C,$00 ;U
	dc.b $24,$66,$66,$66,$66,$3C,$18,$00 ;V
	dc.b $44,$C6,$D6,$D6,$FE,$EE,$44,$00 ;W
	dc.b $C6,$6C,$38,$38,$6C,$C6,$44,$00 ;X
	dc.b $24,$66,$66,$3C,$18,$18,$08,$00 ;Y
	dc.b $7C,$FC,$0C,$18,$30,$7E,$7C,$00 ;Z
	
VDPSettings:
	dc.b 4,4,$30,$3C,$07,$6C,0,0,0,0,$FF,0,$81,$37,0,2,1,0,0
	

Message: dc.b 'Tails is a girl',255
	
	
	even		;word align after byte data