MACHINE 68000
    
    INCDIR  "c:/Users/capitano/Documents/giochino/"
    INCLUDE "custom.i"
    
    SECTION Code,CODE_C

START:
    ; Don't use OS calls - we're booting from scratch
    lea     CUSTOM,a6

    ; Save old DMA/INT state
    move.w  DMACONR(a6),d0
    or.w    #$8000,d0
    move.w  d0,OldDmaCon
    move.w  INTENAR(a6),d0
    or.w    #$8000,d0
    move.w  d0,OldIntEna

    ; Disable interrupts and DMA
    move.w  #$7FFF,INTENA(a6)
    move.w  #$7FFF,DMACON(a6)
    move.w  #$7FFF,INTREQ(a6)

    ; Setup 1 bitplane display
    move.w  #$1200,BPLCON0(a6)
    move.w  #0,BPLCON1(a6)
    move.w  #0,BPLCON2(a6)
    move.w  #0,BPL1MOD(a6)
    
    ; Display window
    move.w  #$2c81,DIWSTRT(a6)
    move.w  #$2cc1,DIWSTOP(a6)
    move.w  #$0038,DDFSTRT(a6)
    move.w  #$00d0,DDFSTOP(a6)

    ; Set bitplane pointer
    lea     Screen(pc),a0
    move.l  a0,d0
    move.w  d0,BPL1PTL(a6)
    swap    d0
    move.w  d0,BPL1PTH(a6)

    ; Set colors
    move.w  #$0000,COLOR00(a6)  ; Black background
    move.w  #$0FF0,COLOR01(a6)  ; Green text

    ; Setup Copper (simple - just colors)
    lea     CopperList(pc),a0
    move.l  a0,d0
    move.w  d0,COP1LCL(a6)
    swap    d0
    move.w  d0,COP1LCH(a6)
    move.w  #0,COPJMP1(a6)

    ; Enable DMA
    move.w  #$83C0,DMACON(a6)

    ; Clear screen
    lea     Screen(pc),a0
    move.w  #(40*256)/4-1,d0
.clear:
    move.l  #0,(a0)+
    dbf     d0,.clear

    ; Draw simple text
    lea     WelcomeMsg(pc),a0
    moveq   #5,d0           ; X
    moveq   #10,d1          ; Y
    bsr     DrawText

MAIN_LOOP:
    ; Wait VBlank
    bsr     WaitVBlank
    
    ; Check mouse button to exit
    btst    #6,CIAA
    bne.s   MAIN_LOOP

EXIT:
    ; Restore and exit (reboot)
    lea     CUSTOM,a6
    move.w  #$7FFF,DMACON(a6)
    move.w  #$7FFF,INTENA(a6)
    
    ; Cold reboot
    lea     $1000000,a0
    jmp     (a0)

WaitVBlank:
    lea     CUSTOM,a6
.wait:
    move.l  $04(a6),d0
    and.l   #$1ff00,d0
    cmp.l   #300<<8,d0
    bne.s   .wait
    rts

; DrawText - Simple version
; a0=string, d0=X, d1=Y
DrawText:
    movem.l d0-d3/a0-a2,-(sp)
    lea     Screen(pc),a1
    mulu    #320,d1
    add.l   d1,a1
    add.w   d0,a1

.loop:
    move.b  (a0)+,d2
    beq.s   .done
    cmp.b   #32,d2
    blt.s   .loop
    
    sub.b   #32,d2
    ext.w   d2
    lea     Font8x8(pc),a2
    lsl.w   #3,d2
    add.w   d2,a2

    move.b  (a2)+,(a1)
    move.b  (a2)+,40(a1)
    move.b  (a2)+,80(a1)
    move.b  (a2)+,120(a1)
    move.b  (a2)+,160(a1)
    move.b  (a2)+,200(a1)
    move.b  (a2)+,240(a1)
    move.b  (a2)+,280(a1)

    addq.w  #1,a1
    bra.s   .loop

.done:
    movem.l (sp)+,d0-d3/a0-a2
    rts

; Data
    CNOP 0,4
CopperList:
    DC.W    COLOR00,$0000
    DC.W    COLOR01,$0FF0
    DC.W    $FFFF,$FFFE

WelcomeMsg:
    dc.b    "OFFICE EMAIL GAME",0
    dc.b    "CLICK MOUSE TO EXIT",0

OldDmaCon:  dc.w    0
OldIntEna:  dc.w    0

    CNOP 0,2
Font8x8:
    ; Minimal font (space + A-Z)
    dc.b $00,$00,$00,$00,$00,$00,$00,$00 ; Space
    dcb.b 8*15,0  ; Skip to A
    dc.b $18,$24,$42,$42,$7E,$42,$42,$00 ; A
    dc.b $7C,$42,$42,$7C,$42,$42,$7C,$00 ; B
    dc.b $3C,$42,$40,$40,$40,$42,$3C,$00 ; C
    dc.b $78,$44,$42,$42,$42,$44,$78,$00 ; D
    dc.b $7E,$40,$40,$78,$40,$40,$7E,$00 ; E
    dc.b $7E,$40,$40,$78,$40,$40,$40,$00 ; F
    dc.b $3C,$42,$40,$4E,$42,$42,$3C,$00 ; G
    dc.b $42,$42,$42,$7E,$42,$42,$42,$00 ; H
    dc.b $3C,$18,$18,$18,$18,$18,$3C,$00 ; I
    dc.b $06,$06,$06,$06,$06,$46,$3C,$00 ; J
    dc.b $44,$48,$50,$60,$50,$48,$44,$00 ; K
    dc.b $40,$40,$40,$40,$40,$40,$7E,$00 ; L
    dc.b $42,$66,$5A,$42,$42,$42,$42,$00 ; M
    dc.b $42,$62,$52,$4A,$46,$42,$42,$00 ; N
    dc.b $3C,$42,$42,$42,$42,$42,$3C,$00 ; O
    dc.b $7C,$42,$42,$7C,$40,$40,$40,$00 ; P
    dc.b $3C,$42,$42,$42,$52,$4A,$3C,$00 ; Q
    dc.b $7C,$42,$42,$7C,$48,$44,$42,$00 ; R
    dc.b $3C,$40,$40,$3C,$02,$02,$3C,$00 ; S
    dc.b $7E,$18,$18,$18,$18,$18,$18,$00 ; T
    dc.b $42,$42,$42,$42,$42,$42,$3C,$00 ; U
    dc.b $42,$42,$42,$42,$42,$24,$18,$00 ; V
    dc.b $42,$42,$42,$5A,$5A,$66,$42,$00 ; W
    dc.b $42,$24,$18,$18,$18,$24,$42,$00 ; X
    dc.b $42,$42,$24,$18,$18,$18,$18,$00 ; Y
    dc.b $7E,$04,$08,$10,$20,$40,$7E,$00 ; Z

    CNOP 0,4
Screen:
    ds.b    40*256

    END