Not sure if this is widely known but I was wondering how the old genesis homebrew and warez scene did their intros and hacks and stuff. I found the answer to that and yeah it's pretty interesting to see how they did it. Seems they knew more than we expected them to do, no? Code (Text): * * * MEGA DRIVE hard initial program * * 1990 6/6 * R/D 5 * * ++++++++++++++++++++++++++++++++++++++++++++++++++ * + status of MEGA_DRIVE on program_finished + * ++++++++++++++++++++++++++++++++++++++++++++++++++ * * ****************** 68000 ******************* * --------- CAUTION ----------- * When program end * * 68000 set RESET to Z80 ($A11100=0,$A11200=$000) * * Z80 wait [ JP (HL) ] command ( HL=0000 ) * * ************************************************************* * * * * * ICD_END is GAME_PROGRAM start_address * * * ICD_END = START+$100 * * * this program size is just 256 byte. * * * * * ************************************************************* ; ; ; ;*************************************************** ;**************** Attention ************************ ;You have to set this program at your program start. ;Don't change this program. ;*************************************************** ;program start START: tst.l $a10008 ; power on check cntl_A,cntl_B bne.s h_s ; reset hot_start tst.w $a1000c ; power on check cntl_C h_s: bne.s hot_start ; reset hot_start cold_start: ; power on (cold_start) lea.l reg_set(pc),a5 ; register set table movem.w (a5)+,d5-d7 ; d5/d6/d7 movem.l (a5)+,a0-a4 ; a0-a5 security: ; ** a1=$a11100 ** move.b -$10ff(a1),d0 ; -$1101(a1)=$a10000 andi.b #$000f,d0 ; Ver.No check beq.s japan move.l #"SEGA",$2f00(a1) ; security part move "SEGA" japan: ; $2F00(A1)=$A14000 reg_ini: move (a4),d0 ; VDP STATUS DUMMY READ (D5=$8000) moveq #0,d0 ; D0 set 0 move.l d0,a6 ; A6 $00000000 move.l a6,usp ; User Stack Pointer moveq #23,d1 ; D1 count VDP_command r_ini1: move.b (a5)+,d5 ; REG 0-23 SET (DMA FILL SET) move.w d5,(a4) ; add d7,d5 ; d7=$100 dbra d1,r_ini1 dma_fill: ; already set REG#18,19,23 move.l (a5)+,(a4) ; dma fill(VDP_VRAM CLEAR) move d0,(a3) ; fill data set $0,$C00000 z80_clr: ; Z80 self_initial move d7,(a1) ; Z80_BUSREQ ON move d7,(a2) ; Z80_RESET OFF z801: btst d0,(a1) ; Z80_BGACK CHECK ? bne.s z801 moveq #37,d2 ; D2 is Z80_program's size z802: move.b (a5)+,(a0)+ ; move.B (z80_prg)+,($a00000)+ dbra d2,z802 move d0,(a2) ; Z80_RESET ON move d0,(a1) ; Z80_BUSREQ OFF move d7,(a2) ; Z80_RESET OFF(Z80 start) clr_wk: ; A6=$0 D0=$0 D6=$3FFF c_wk1: move.l d0,-(a6) ; wrok ram clear dbra d6,c_wk1 ; clr_col move.l (a5)+,(a4) ; VDP REG#1=04,#15=02 move.l (a5)+,(a4) ; a3=$c00000 a4=$c00004 d0=$0 moveq #$1f,d3 ; d3 is color_ram's size/2(WORD) c_col1: move.l d0,(a3) ; vdp_color clear dbra d3,c_col1 clr_vsc: move.l (a5)+,(a4) ; a3=$c00000 a4=$c00004 d0=$0 moveq #19,d4 ; d4 count Vscroll_ram c_vsc1: move.l d0,(a3) ; vdp_vscroll clear dbra d4,c_vsc1 clr_psg: moveq #3,d5 ; d5 is byte_size of PSG init_DATA c_psg1: move.b (a5)+,$11(a3) ; PSG_SOUND clear dbra d5,c_psg1 move d0,(a2) ; Z80 RESET movem.l (a6),d0-d7/a0-a6; register all initial move #$2700,sr ;68000 register initial hot_start: bra.s chk_vdp ; init_end: reg_set: dw $008000,$003fff,$000100 ;d5/d6/d7 dl $a00000,$a11100,$a11200,$c00000 ;a0-a3 dl $c00004 ;a4 vreg_dt: db $04,$14,$30,$3c,$07,$6c,$00,$00 ;VDP REG #0-7 db $00,$00,$ff,$00,$81,$37,$00,$01 ;VDP_REG #8-15 db $01,$00,$00,$ff,$ff,$00,$00,$80 ;VDP_REG #16-23 dma_fill_data: dl $40000080 ;dma fill(VDP_VRAM clear) z80_prg: DB $AF ;XOR A DB $01,$D9,$1F ;LD BC,1FD9H DB $11,$27,$00 ;LD DE,0027H DB $21,$26,$00 ;LD HL,0026H DB $F9 ;LD SP,HL DB $77 ;LD (HL),A DB $ED,$B0 ;LDIR DB $DD,$E1 ;POP IX DB $FD,$E1 ;POP IY DB $ED,$47 ;LD I,A DB $ED,$4F ;LD R,A DB $D1 ;POP DE DB $E1 ;POP HL DB $F1 ;POP AF DB $08 ;EX AF,AF' DB $D9 ;EXX DB $C1 ;POP BC DB $D1 ;POP DE DB $E1 ;POP HL DB $F1 ;POP AF DB $F9 ;LD SP,HL DB $F3 ;DI DB $ED,$56 ;IM1 DB $36,$E9 ;LD (HL),$E9='JP (HL)' DB $E9 ;JP (HL) new_reg_data: dl $81048f02 ;VDP REG#1=04,#15=02 clr_col_data: dl $c0000000 ;color_ram address data clr_vsc_data: dl $40000010 ;v_scroll ram address data psg_dat: DB $9F,$BF,$DF,$FF;PSG initial data chk_vdp: tst $c00004 ICD_END: edit: TABS fixed
I recognize this. It's from Barry Leitch's sound source code collection. http://gilgalad.arc-nova.org/nes-source/Barry%20Leitch/ I found this quite a while back while searching for official copies of ICD_BLK4, I just didn't think it was worth bringing up/brought it up and nobody cared. Anyway, have fun with the code in there, it's actually official game code iirc. :P (Games use GEMS btw for Genesis, so no SMPS official source code :<)
