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dc.l $0, start
dc.l empty_handler
dc.l empty_handler
;$10
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$20
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$30
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$40
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$50
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$60
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$70
dc.l int_4
dc.l empty_handler
dc.l int_6
dc.l empty_handler
;$80
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$90
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$A0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$B0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$C0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$D0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$E0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
;$F0
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.l empty_handler
dc.b "SEGA GENESIS "
dc.b "(c) 2015.JULY "
dc.b "Menu "
dc.b " "
dc.b " "
dc.b "Menu "
dc.b " "
dc.b " "
dc.b "GM MK-00000-00", 0, 0
dc.b " "
dc.l $0, rom_end-1, $FF0000, $FFFFFF
dc.b " "
dc.b " "
dc.b " "
dc.b " "
dc.b "JUE "
empty_handler:
int_6:
rte
int_4:
rte
rsset $FFFF8000
x_pos rs.w 1
base_cmd rs.l 1
start:
lea $C00000, a0
lea $C00004, a1
move.w #$8104, (a1) ;Mode 5, everything turned off
move.w #$8004, (a1)
move.w #$8220, (a1) ;Scroll a table $8000
move.w #$8405, (a1) ;Scroll b table $A000
move.w #$8560, (a1) ;SAT table $C000
move.w #$8700, (a1) ;backdrop color 0
move.w #$8B00, (a1) ;full screen scroll
move.w #$8C87, (a1) ;40 cell mode, double-res interlace
move.w #$8D00, (a1) ;hscroll table at 0
move.w #$8F02, (a1) ;autoinc 2
move.w #$9001, (a1) ;64x32 scroll size
move.l #$C0000000, (a1)
move.w #$000, (a0)
move.w #$EEE, (a0)
;init scroll table
move.l #$40000000, (a1)
move.w #0, (a0)
move.w #4, (a0)
;load tiles
move.l #$48000000, (a1)
lea font(pc), a2
move.w #((fontend-font)/4 - 1), d0
tloop:
move.l (a2)+, (a0)
dbra d0, tloop
;clear name table
move.l #$40000002, (a1)
moveq #32, d0
move.w #(64*64-1), d1
ploop:
move.w d0, (a0)
dbra d1, ploop
move.l #$40000002, d3,
move.l d3, (a1)
move.l d3, base_cmd.w
lea Message(pc), a6
moveq #0, d0
bsr print_string
move.w #$8144, (a1) ;enable display
move #$2300, sr
wait_forever
bra wait_forever
Message:
dc.b "Journey From Darkness - Strider Returns (U) [c][!].bin", $A
dc.b "Toejam & Earl in Panic on Funkotron (U) [!].bin", $A
dc.b "Fire Shark (U) [c][!].bin", $A
dc.b "Sonic and Knuckles (W) [!].bin", 0
align 1
;Prints a null terminated string
;a6 - pointer to string
;a0 - VDP data port
;d0 - base tile attribute
;
;Clobbers: d1.w, d2.w, d3.l
print_string:
lea widths(pc), a5
move.w x_pos.w, d2
move.l base_cmd.w, d3
.loop
moveq #0, d1
move.b (a6)+, d1
beq .end
cmp.b #$A, d1
beq .newline
tst.b (-32, a5, d1.w)
beq .narrow
add.w d0, d1
move.w d1, (a0)
addq #2, d2
bra .loop
.narrow
add.w d0, d1
move.w d1, (a0)
addq #1, d2
move.l d2, d1
;switch to other plane
and.w #$FFFE, d1
swap d1
eor.l #$20000000, d3
or.l d3, d1
move.l d1, (a1)
bra .loop
.newline
moveq #0, d2
;switch back to plane A
and.l #$DFFFFFFF, d3
;skip to next row
add.l #$00800000, d3
move.l d3, (a1)
bra .loop
.end
move.w d2, x_pos.w
move.l d3, base_cmd.w
rts
align 1
font:
incbin font_interlace_variable.tiles
fontend
widths:
dc.b 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1
dc.b 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0
dc.b 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1
dc.b 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1
dc.b 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1
rom_end:
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