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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"
empty_handler:
int_6:
rte
int_4:
move.w (a2), d0
ori.w #$8000, d0
move.w d0, (a4)+
rte
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 #$8404, (a1) ;Scroll b table $8000
move.w #$8560, (a1) ;SAT table $C000
move.w #$8700, (a1) ;backdrop color 0
move.w #$8B00, (a1) ;full screen scroll
move.w #$8C81, (a1) ;40 cell mode, no interlace
move.w #$8C81, (mode).w
move.w #$8D00, (a1) ;hscroll table at 0
move.w #$8F02, (a1) ;autoinc 2
move.w #$9011, (a1) ;64x64 scroll size
move.l #$C0000000, (a1)
move.w #$000, (a0)
move.w #$EEE, (a0)
;clear scroll table
move.l #$40000000, (a1)
move.l #0, (a0)
;load tiles
move.l #$44000000, (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
lea $FF0000, a4
move.b #$40, (a4, 6)
move.w #$8144, (a1) ;enable display
move #$2300, sr
lea (4, a1), a2 ;hv counter line address
lea (2, a1), a3 ;second contro/status address
move.b #254, d0
init_wait:
cmp.b (a2), d0
beq init_wait
top:
move.b #254, d0
lea $FF0000, a4
move.w #$8F00, (a1) ;autoinc of 0
move.l #$40040000, (a1) ;unused VRAM address
wait_active:
cmp.b (a2), d0
bne.s wait_active
move.l #$8A718014, (a1) ;enable Hints
;sync to VDP by attempting to fill FIFO
;being in vblank makes this a bit difficult
rept 8
move.l d0, (a0)
endr
;sample data for vblank flag off
rept 82 ;two lines worth of move.l
move.l (a3), (a4)+
endr
move.l a4, a5 ;save end of first buffer
move.b (a2), d0
wait_new_line:
cmp.b (a2), d0
beq.s wait_new_line
;sync to VDP by filling FIFO
move.l d0, (a0)
move.l d0, (a0)
move.w d0, (a0)
;sample data for line change HV value
rept 45 ;one line worth of move.l
move.l (a2), (a4)+
endr
move.l a4, usp ;save end of second buffer
moveq #$70, d0
wait_hint_line:
cmp.b (a2), d0
bne.s wait_hint_line
;sample data for line change HV value
rept 45 ;one line worth of move.l
move.l (a2), (a4)+
endr
move.l a4, a6
move.b #223, d0
wait_inactive:
cmp.b (a2), d0
bne.s wait_inactive
;sync to VDP by filling FIFO
move.l d0, (a0)
move.l d0, (a0)
move.w d0, (a0)
;sample data for vblank on
rept 82 ;two lines worth of move.l
move.l (a3), (a4)+
endr
move.l #$8AFF8004, (a1) ;disable Hints
rsset $FFFF8000
vblank_start_min rs.w 1
vblank_start_max rs.w 1
vblank_end_min rs.w 1
vblank_end_max rs.w 1
hblank_start_min rs.w 1
hblank_start_max rs.w 1
hblank_end_min rs.w 1
hblank_end_max rs.w 1
line_change_min rs.w 1
line_change_max rs.w 1
hint_min rs.w 1
hint_max rs.w 1
mode rs.w 1
printed_hv_dump rs.b 1
button_state rs.b 1
lea $FF0001, a4
.loop:
btst.b #3, (a4)
beq.s found_vblank_off
move.w 1(a4), d6
addq #4, a4
bra.s .loop
found_vblank_off:
move.w (vblank_end_max).w, d0
beq .new_max
cmp.w d0, d6
blo .no_new_max
.new_max
move.w d6, (vblank_end_max).w
.no_new_max:
move.w 1(a4), d6
move.w (vblank_end_min).w, d0
beq .new_min
cmp.w d0, d6
bhi .no_new_min
.new_min
move.w d6, (vblank_end_min).w
.no_new_min:
lea $FF0001, a4
;first find a point where HBLANK is not set
bra.s .start
.loop:
addq #4, a4
.start
btst.b #2, (a4)
bne.s .loop
;then find a point after that where it switches to on
.loop2:
btst.b #2, (a4)
bne.s found_hblank_on
move.w 1(a4), d5
addq #4, a4
bra.s .loop2
found_hblank_on:
move.w (hblank_start_max).w, d0
beq .new_max
cmp.w d0, d5
blo .no_new_max
.new_max
move.w d5, (hblank_start_max).w
.no_new_max:
move.w 1(a4), d5
move.w (hblank_start_min).w, d0
beq .new_min
cmp.w d0, d5
bhi .no_new_min
.new_min
move.w d5, (hblank_start_min).w
.no_new_min:
;finally find a point after that where it switches back off
.loop2:
btst.b #2, (a4)
beq.s found_hblank_off
move.w 1(a4), d5
addq #4, a4
bra.s .loop2
found_hblank_off:
move.w (hblank_end_max).w, d0
beq .new_max
cmp.w d0, d5
blo .no_new_max
.new_max
move.w d5, (hblank_end_max).w
.no_new_max:
move.w 1(a4), d5
move.w (hblank_end_min).w, d0
beq .new_min
cmp.w d0, d5
bhi .no_new_min
.new_min
move.w d5, (hblank_end_min).w
.no_new_min:
move.l a5, a4 ;save line change buffer for later
move.b (a5), d0
.loop
move.w (a5), d7
addq #2, a5
cmp.b (a5), d0
beq .loop
found_line_change:
move.w (line_change_max).w, d0
beq .new_max
cmp.w d0, d7
blo .no_new_max
.new_max
move.w d7, (line_change_max).w
.no_new_max:
move.w (a5), d7
move.w (line_change_min).w, d0
beq .new_min
cmp.w d0, d7
bhi .no_new_min
.new_min
move.w d7, (line_change_min).w
.no_new_min:
addq #1, a6
.loop:
btst.b #3, (a6)
bne.s found_vblank_on
move.w 1(a6), d5
addq #4, a6
bra.s .loop
found_vblank_on:
move.w (vblank_start_max).w, d0
beq .new_max
cmp.w d0, d5
blo .no_new_max
.new_max
move.w d5, (vblank_start_max).w
.no_new_max:
move.w 1(a6), d5
move.w (vblank_start_min).w, d0
beq .new_min
cmp.b d0, d5
bhi .no_new_min
.new_min
move.w d5, (vblank_start_min).w
.no_new_min:
move usp, a5
.loop:
btst.b #7, (a5)
bne.s found_hint
move.w (a5), d1
addq #2, a5
bra.s .loop
found_hint:
move.w (hint_max).w, d0
beq .new_max
cmp.w d0, d1
blo .no_new_max
.new_max
move.w d1, (hint_max).w
.no_new_max:
move.w (a5), d1
and.w #$7FFF, d1
move.w (hint_min).w, d0
beq .new_min
cmp.b d0, d1
bhi .no_new_min
.new_min
move.w d1, (hint_min).w
.no_new_min:
draw_info:
;draw data
move.w #$8F02, (a1) ;autoinc of 2
move.l #$40840002, (a1)
moveq #0, d0
lea VBlankStart(pc), a6
bsr print_string
move.w (vblank_start_max), d0
moveq #0, d1
bsr print_hexw
move.w #32, (a0)
move.w d5, d0
bsr print_hexw
move.w #32, (a0)
move.w (vblank_start_min), d0
bsr print_hexw
moveq #0, d0
move.l #$41040002, (a1)
lea VBlankEnd(pc), a6
bsr print_string
;max value before vblank end
moveq #0, d1
move.w (vblank_end_max), d0
bsr print_hexw
move.w #32, (a0)
move.w d6, d0
bsr print_hexw
;min value after vblank end
move.w (vblank_end_min), d0
move.w #32, (a0)
bsr print_hexw
moveq #0, d0
move.l #$41840002, (a1)
lea LineChange(pc), a6
bsr print_string
move.w (line_change_max), d0
moveq #0, d1
bsr print_hexw
move.w #32, (a0)
move.w d7, d0
bsr print_hexw
move.w (line_change_min), d0
move.w #32, (a0)
bsr print_hexw
moveq #0, d0
move.l #$42040002, (a1)
lea HBlankStart(pc), a6
bsr print_string
move.w (hblank_start_max), d0
moveq #0, d1
bsr print_hexw
move.w (hblank_start_min), d0
move.w #32, (a0)
bsr print_hexw
moveq #0, d0
move.l #$42840002, (a1)
lea HBlankEnd(pc), a6
bsr print_string
move.w (hblank_end_max), d0
moveq #0, d1
bsr print_hexw
move.w (hblank_end_min), d0
move.w #32, (a0)
bsr print_hexw
moveq #0, d0
move.l #$43040002, (a1)
lea HInterrupt(pc), a6
bsr print_string
move.w (hint_max), d0
moveq #0, d1
bsr print_hexw
move.w (hint_min), d0
move.w #32, (a0)
bsr print_hexw
;read pad
move.b #$40, $A10003
move.b $A10003, d0
move.b #$00, $A10003
and.b #$3f, d0
move.b $A10003, d1
and.b #$30, d1
lsl.b #2, d1
or.b d1, d0
not.b d0
move.b (button_state).w, d2
eor.b d0, d2
and.b d0, d2
move.b d2, d3 ;d3 contains newly pressed buttons, SACBRLDU
move.b d0, (button_state).w
btst.l #7, d3
beq not_pressed
moveq #0, d0
move.l d0, (vblank_start_min).w
move.l d0, (vblank_end_min).w
move.l d0, (hblank_start_min).w
move.l d0, (hblank_end_min).w
move.l d0, (line_change_min).w
move.l d0, (hint_min).w
move.b d0, (printed_hv_dump).w
move.w (mode).w, d0
eor.w #$81, d0
move.w d0, (mode).w
move.w d0, (a1)
bra top
not_pressed
move.b (printed_hv_dump).w, d0
bne top
move.b #1, (printed_hv_dump).w
moveq #0, d1
moveq #89, d4
moveq #6, d5
move.l #$45820002, d6
move.l d6, (a1)
print_loop:
dbra d5, .no_line_change
;#$45820002
add.l #$00800000, d6
move.l d6, (a1)
moveq #5, d5
.no_line_change
move.w #32, (a0)
move.w (a4)+, d0
bsr print_hexw
dbra d4, print_loop
add.l #$01020000, d6
move.l d6, (a1)
moveq #0, d0
lea Instructions(pc), a6
bsr print_string
bra top
VBlankStart:
dc.b "VBlank Start: ", 0
VBlankEnd:
dc.b "VBlank End: ", 0
LineChange:
dc.b "Line Change: ", 0
HBlankStart:
dc.b "HBlank Start: ", 0
HBlankEnd:
dc.b "HBlank End: ", 0
HInterrupt:
dc.b "HInterrupt: ", 0
Instructions:
dc.b "Press Start to switch modes", 0
align 1
;Prints a number in hex format
;d0.w - number to print
;d1.w - base tile attribute
;a0 - VDP data port
;
;Clobbers: d2.l, d3.l
;
print_hexw:
moveq #3, d3
.digitloop
rol.w #4, d0
moveq #$F, d2
and.b d0, d2
cmp.b #$A, d2
bge .hex
add.w #$30, d2
bra .makeattrib
.hex
add.w #($41-$A), d2
.makeattrib
add.w d1, d2
move.w d2, (a0)
dbra d3, .digitloop
rts
;Prints a null terminated string
;a6 - pointer to string
;a0 - VDP data port
;d0 - base tile attribute
;
;Clobbers: d1.w
print_string:
.loop
moveq #0, d1
move.b (a6)+, d1
beq .end
add.w d0, d1
move.w d1, (a0)
bra .loop
.end
rts
align 1
font:
incbin font.tiles
fontend
|
