used motorola 68330 processor
created ram FFFF0000 size(?) FFFFFFFE
went to 0440 and hit C
In that area I see this
Code: Select all
ROM:00000440 ; ---------------------------------------------------------------------------
ROM:00000440 suba.l a6,a6
ROM:00000442 move.l #$FFFFA800,d0
ROM:00000448 asr.l #8,d0
ROM:0000044A move.w d0,($FFFFFB04).w
ROM:0000044E move.l #$FFFF8000,d0
ROM:00000454 move.l d0,($FFFFFB44).w
ROM:00000458 move.l #$FFFF9000,d0
ROM:0000045E move.l d0,($FFFFFB84).w
ROM:00000462 move.l #$FFFFA000,d0
ROM:00000468 move.l d0,($FFFFFA84).w
ROM:0000046C move.l #$FFFFB000,d0
ROM:00000472 move.l d0,($FFFFFAC4).w
ROM:00000476 move.l #$200,d0
ROM:0000047C move.w d0,($FFFFFB40).w
ROM:00000480 move.w d0,($FFFFFB80).w
ROM:00000484 move.w d0,($FFFFFA80).w
ROM:00000488 move.w d0,($FFFFFAC0).w
ROM:0000048C movea.l #0,a0
ROM:00000492 movec a0,vbr
ROM:00000496 movea.l #$FFFFB800,sp
ROM:0000049C jsr (sub_E52).l
ROM:000004A2 move.b ($FFFFFA07).w,d0
ROM:000004A6 btst #6,d0
ROM:000004AA beq.s loc_4BA
ROM:000004AC clr.w ($FFFF8DE0).w
ROM:000004B0 clr.l ($FFFF8DE2).w
ROM:000004B4 clr.w ($FFFF8DE6).w
ROM:000004B8 bra.s loc_4D2
ROM:000004BA ; ---------------------------------------------------------------------------
ROM:000004BA
ROM:000004BA loc_4BA: ; CODE XREF: ROM:000004AAj
ROM:000004BA addq.w #1,($FFFF8DE6).w
ROM:000004BE btst #5,d0
ROM:000004C2 beq.s loc_4CA
ROM:000004C4 tst.b ($FFFF8DE0).w
ROM:000004C8 bne.s loc_4D2
ROM:000004CA
ROM:000004CA loc_4CA: ; CODE XREF: ROM:000004C2j
ROM:000004CA andi.w #$FF,d0
ROM:000004CE move.w d0,($FFFF8DE0).w
ROM:000004D2
ROM:000004D2 loc_4D2: ; CODE XREF: ROM:000004B8j
ROM:000004D2 ; ROM:000004C8j
ROM:000004D2 movea.l #$FFB800,sp
ROM:000004D8 jsr (sub_1774).l
ROM:000004DE jsr sub_1A23C
ROM:000004E4 tst.w (word_1834).l
ROM:000004EA beq.s loc_4F2
ROM:000004EC jsr loc_69870
ROM:000004F2
ROM:000004F2 loc_4F2: ; CODE XREF: ROM:000004EAj
ROM:000004F2 movea.l (off_1830).l,a2
ROM:000004F8 jsr (a2)
ROM:000004FA stop #$2700
ROM:000004FE
ROM:000004FE ; =============== S U B R O U T I N E =======================================
ROM:000004FE
ROM:000004FE
ROM:000004FE sub_4FE: ; CODE XREF: sub_7BC+11Ep
ROM:000004FE ; sub_8F8+18Cp ...
ROM:000004FE move.w #$FFFF,($FFFF8DE0).w
ROM:00000504 move.l (sp),d0
ROM:00000506 move.l d0,($FFFF8DE2).w
ROM:0000050A stop #$2700
ROM:0000050A ; End of function sub_4FE
ROM:0000050A
ROM:0000050E
ROM:0000050E ; =============== S U B R O U T I N E =======================================
ROM:0000050E
ROM:0000050E
ROM:0000050E sub_50E: ; DATA XREF: ROM:off_28o
ROM:0000050E ; ROM:off_44o ...
ROM:0000050E
ROM:0000050E arg_2 = 6
ROM:0000050E
ROM:0000050E move.w arg_2(sp),d0
ROM:00000512 andi.w #$FFF,d0
ROM:00000516 asl.w #6,d0
ROM:00000518 move.w d0,($FFFF8DE0).w
ROM:0000051C move.l 2(sp),d0
ROM:00000520 move.l d0,($FFFF8DE2).w
ROM:00000524 stop #$2700
ROM:00000524 ; End of function sub_50E
ROM:00000524
ROM:00000524 ; ---------------------------------------------------------------------------
I attach the file- the processor type is 6833x
- create a RAM segment from FFFF0000 to FFFFFFFE (it's not really there but IDA cannot handle 24bit relative addys.)
- the RESET vector is at 0x04 (generally it is 0x0440)
- go to 0x0440 and start disassembly
- you'll see a number of CPU setup and PCM interity checking routines
- then you'll se an indexed jumpt to the main routines.
