Gameboy Development Forum

mjm · 2013-02-18 20:42:04

Hello everybody,

I've started to write my own ROMs disassembler, how does it work now:
I start at offset 0x0100 of ROM image and try to interpret content according to [2]. I don't emulate processor (except bank switching), only follow control instructions (CALL, JP, JR, RST) when needed. When the control instruction is unconditional (JP a16, JR r8 etc.) I follow the specified address, when it is conditional I follow both addresses (e.g. CALL NZ,a16, I follow the a16 and then return to pc+3 address). There is only one control instruction, that parameter address can change dynamically - JP (HL), all other control instructions have fixed address (I ignore this instruction, haven't seen it being used yet).

edit: available at https://github.com/mmuszkow/gb-disasm

It works with ROMs from [1], but when trying to disassemble something a little bit more complex like Dr.Mario (32KB Cart, ROM Only), I think the output is incorrect (e.g. in one place I have jump which address seems incorrect to me - JP C,$8F04).

I have some concerns:
1. RST instruction, I skip this instruction (pc += 1), if I understand correctly it is some kind of internal "function" call. Is this OK?
2. Address translation, at the beginning I want to be able to interpret 2 kinds of ROMs:
- ROM only - address is mapped directly to offset in ROM image (0x0000 - 0x7FFF).
- MBC1 - adresses 0x0000-0x3FFF are mapped directly to offset in ROM, adresses 0x4000-0x7FFF are mapped to (bank*0x4000)+addr in ROM image. Is this OK?
3. Are there any "original" ROMs dis-assemblies I can test on? I have found only Pokemon, but it's to complex to be analyzed. I'm looking for something simpler, preferably 32KB ROM or MBC1.

[1] http://www.devrs.com/gb/asmcode.php
[2] http://pastraiser.com/cpu/gameboy/gameboy_opcodes.html

Example of Dr.Mario disassembly:

Code:

[0x00000100] 0x00           NOP
[0x00000101] 0xC3 0x50 0x01 JP,$0150
[0x00000150] 0xC3 0xE8 0x01 JP,$01E8
[0x00000153] 0x01 0x0E 0xD0 LD BC,$D00E
[0x00000156] 0x0A           LD A,(BC)
[0x00000157] 0xA7           AND A
[0x00000158] 0x20 0x0D      JR NZ,$0D
[0x0000015A] 0xF0 0xCF      LDH A,($CF)
[0x0000015C] 0xFE 0xFE      CP,$FE
[0x0000015E] 0x20 0x04      JR NZ,$04
[0x00000160] 0x3E 0x01      LD A,$01
[0x00000162] 0x18 0x01      JR,$01
[0x00000164] 0xAF           XOR A
[0x00000165] 0x02           LD (BC),A
[0x00000166] 0xC9           RET
[0x00000167] 0xFA 0x46 0xD0 LD A,($D046)
[0x0000016A] 0xE0 0x01      LDH ($01),A
[0x0000016C] 0x18 0xF6      JR,$F6
[0x000001E8] 0xAF           XOR A
[0x000001E9] 0x21 0xFF 0xDF LD HL,$DFFF
[0x000001EC] 0x0E 0x10      LD C,$10
[0x000001EE] 0x06 0x00      LD B,$00
[0x000001F0] 0x32           LD (HL-),A
[0x000001F1] 0x05           DEC B
[0x000001F2] 0x20 0xFC      JR NZ,$FC
[0x000001F4] 0x0D           DEC C
[0x000001F5] 0x20 0xF9      JR NZ,$F9
[0x000001F7] 0x3E 0x0D      LD A,$0D
[0x000001F9] 0xF3           DI
[0x000001FA] 0xE0 0x0F      LDH ($0F),A
[0x000001FC] 0xE0 0xFF      LDH ($FF),A
[0x000001FE] 0xAF           XOR A
[0x000001FF] 0xE0 0x42      LDH ($42),A
[0x00000201] 0xE0 0x43      LDH ($43),A
[0x00000203] 0xE0 0xA4      LDH ($A4),A
[0x00000205] 0xE0 0x41      LDH ($41),A
[0x00000207] 0xE0 0x01      LDH ($01),A
[0x00000209] 0xE0 0x02      LDH ($02),A
[0x0000020B] 0xEA 0x00 0xD0 LD ($D000),A
[0x0000020E] 0xEA 0x01 0xD0 LD ($D001),A
[0x00000211] 0x3E 0x80      LD A,$80
[0x00000213] 0xE0 0x40      LDH ($40),A
[0x00000215] 0xF0 0x44      LDH A,($44)
[0x00000217] 0xFE 0x94      CP,$94
[0x00000219] 0x20 0xFA      JR NZ,$FA
[0x0000021B] 0x3E 0x03      LD A,$03
[0x0000021D] 0xE0 0x40      LDH ($40),A
[0x0000021F] 0x3E 0xE1      LD A,$E1
[0x00000221] 0xE0 0x47      LDH ($47),A
[0x00000223] 0xE0 0x48      LDH ($48),A
[0x00000225] 0x3E 0xE5      LD A,$E5
[0x00000227] 0xE0 0x49      LDH ($49),A
[0x00000229] 0x21 0x26 0xFF LD HL,$FF26
[0x0000022C] 0x3E 0x80      LD A,$80
[0x0000022E] 0x32           LD (HL-),A
[0x0000022F] 0x3E 0xFF      LD A,$FF
[0x00000231] 0x32           LD (HL-),A
[0x00000232] 0x36 0x77      LD (HL),$77
[0x00000234] 0x21 0x06 0xFF LD HL,$FF06
[0x00000237] 0x3E 0xBF      LD A,$BF
[0x00000239] 0x22           LD (HL+),A
[0x0000023A] 0x3E 0x04      LD A,$04
[0x0000023C] 0x77           LD (HL),A
[0x0000023D] 0x3E 0x01      LD A,$01
[0x0000023F] 0x00           NOP
[0x00000240] 0x00           NOP
[0x00000241] 0x00           NOP
[0x00000242] 0x31 0xFF 0xCF LD SP,$CFFF
[0x00000245] 0xAF           XOR A
[0x00000246] 0x21 0xFF 0xDF LD HL,$DFFF
[0x00000249] 0x06 0x00      LD B,$00
[0x0000024B] 0x32           LD (HL-),A
[0x0000024C] 0x05           DEC B
[0x0000024D] 0x20 0xFC      JR NZ,$FC
[0x0000024F] 0x21 0xFF 0xCF LD HL,$CFFF
[0x00000252] 0x0E 0x10      LD C,$10
[0x00000254] 0x06 0x00      LD B,$00
[0x00000256] 0x32           LD (HL-),A
[0x00000257] 0x05           DEC B
[0x00000258] 0x20 0xFC      JR NZ,$FC
[0x0000025A] 0x0D           DEC C
[0x0000025B] 0x20 0xF9      JR NZ,$F9
[0x0000025D] 0x21 0xFF 0x9F LD HL,$9FFF
[0x00000260] 0x0E 0x20      LD C,$20
[0x00000262] 0xAF           XOR A
[0x00000263] 0x06 0x00      LD B,$00
[0x00000265] 0x32           LD (HL-),A
[0x00000266] 0x05           DEC B
[0x00000267] 0x20 0xFC      JR NZ,$FC
[0x00000269] 0x0D           DEC C
[0x0000026A] 0x20 0xF9      JR NZ,$F9
[0x0000026C] 0x21 0xFF 0xFE LD HL,$FEFF
[0x0000026F] 0x06 0x00      LD B,$00
[0x00000271] 0x32           LD (HL-),A
[0x00000272] 0x05           DEC B
[0x00000273] 0x20 0xFC      JR NZ,$FC
[0x00000275] 0x21 0xFE 0xFF LD HL,$FFFE
[0x00000278] 0x06 0x80      LD B,$80
[0x0000027A] 0x32           LD (HL-),A
[0x0000027B] 0x05           DEC B
[0x0000027C] 0x20 0xFC      JR NZ,$FC
[0x0000027E] 0x0E 0xB6      LD C,$B6
[0x00000280] 0x06 0x0A      LD B,$0A
[0x00000282] 0x21 0x86 0x23 LD HL,$2386
[0x00000285] 0x2A           LD A,(HL+)
[0x00000286] 0xE2           LD (C),A
[0x00000287] 0x0C           INC C
[0x00000288] 0x05           DEC B
[0x00000289] 0x20 0xFA      JR NZ,$FA
[0x0000028B] 0xCD 0xA3 0x20 CALL,$20A3
[0x0000028E] 0xCD 0xF3 0x7F CALL,$7FF3
[0x00000291] 0xCD 0xBB 0x20 CALL,$20BB
[0x00000294] 0x3E 0x0D      LD A,$0D
[0x00000296] 0xE0 0xFF      LDH ($FF),A
[0x00000298] 0x3E 0x80      LD A,$80
[0x0000029A] 0xE0 0x40      LDH ($40),A
[0x0000029C] 0xAF           XOR A
[0x0000029D] 0xE0 0x0F      LDH ($0F),A
[0x0000029F] 0xE0 0x4A      LDH ($4A),A
[0x000002A1] 0xE0 0x4B      LDH ($4B),A
[0x000002A3] 0xE0 0xE1      LDH ($E1),A
[0x000002A5] 0xE0 0x9C      LDH ($9C),A
[0x000002A7] 0xFB           EI
[0x000002A8] 0xF3           DI
[0x000002A9] 0xFA 0xF1 0xC4 LD A,($C4F1)
[0x000002AC] 0xA7           AND A
[0x000002AD] 0x28 0x11      JR Z,$11
[0x000002AF] 0xF0 0xCC      LDH A,($CC)
[0x000002B1] 0xA7           AND A
[0x000002B2] 0x3E 0x00      LD A,$00
[0x000002B4] 0xE0 0xCC      LDH ($CC),A
[0x000002B6] 0x20 0x04      JR NZ,$04
[0x000002B8] 0x3E 0xE0      LD A,$E0
[0x000002BA] 0x18 0x02      JR,$02
[0x000002BC] 0xF0 0xF2      LDH A,($F2)
[0x000002BE] 0xE0 0xD0      LDH ($D0),A
[0x000002C0] 0xFB           EI
[0x000002C1] 0xCD 0x34 0x04 CALL,$0434
[0x000002C4] 0xCD 0x1C 0x23 CALL,$231C
[0x000002C7] 0x21 0x89 0xDF LD HL,$DF89
[0x000002CA] 0x7E           LD A,(HL)
[0x000002CB] 0xA7           AND A
[0x000002CC] 0x28 0x05      JR Z,$05
[0x000002CE] 0xAF           XOR A
[0x000002CF] 0x77           LD (HL),A
[0x000002D0] 0xCD 0x02 0x30 CALL,$3002
[0x000002D3] 0xCD 0x55 0x04 CALL,$0455
[0x000002D3] 0xCD 0x55 0x04 CALL,$0455
[0x000002D6] 0xF0 0xE4      LDH A,($E4)
[0x000002D6] 0xF0 0xE4      LDH A,($E4)
[0x000002D8] 0xA7           AND A
[0x000002D9] 0x20 0x5F      JR NZ,$5F
[0x000002DB] 0xF0 0xB1      LDH A,($B1)
[0x000002DD] 0xA7           AND A
[0x000002DE] 0x28 0x31      JR Z,$31
[0x000002E0] 0xFA 0xF1 0xC4 LD A,($C4F1)
[0x000002E3] 0xA7           AND A
[0x000002E4] 0x28 0x0B      JR Z,$0B
[0x000002E6] 0xF0 0xAB      LDH A,($AB)
[0x000002E8] 0xA7           AND A
[0x000002E9] 0x20 0x06      JR NZ,$06
[0x000002EB] 0xCD 0x64 0x03 CALL,$0364
[0x000002EE] 0xCD 0xE4 0x03 CALL,$03E4
[0x000002F1] 0xF0 0xDE      LDH A,($DE)
[0x000002F1] 0xF0 0xDE      LDH A,($DE)
[0x000002F3] 0xEA 0x8F 0xDF LD ($DF8F),A
[0x000002F6] 0xA7           AND A
[0x000002F7] 0x28 0x0C      JR Z,$0C
[0x000002F9] 0xFE 0x01      CP,$01
[0x000002FB] 0x28 0x0C      JR Z,$0C
[0x000002FD] 0xFE 0x02      CP,$02
[0x000002FF] 0x28 0x0C      JR Z,$0C
[0x00000301] 0x3E 0xD8      LD A,$D8
[0x00000303] 0x18 0x0A      JR,$0A
[0x00000305] 0x3E 0xBF      LD A,$BF
[0x00000307] 0x18 0x06      JR,$06
[0x00000309] 0x3E 0xC8      LD A,$C8
[0x0000030B] 0x18 0x02      JR,$02
[0x0000030D] 0x3E 0xD0      LD A,$D0
[0x0000030F] 0xE0 0x06      LDH ($06),A
[0x00000311] 0xF0 0xCB      LDH A,($CB)
[0x00000313] 0xFE 0x60      CP,$60
[0x00000315] 0x28 0x23      JR Z,$23
[0x00000317] 0xF0 0x80      LDH A,($80)
[0x00000319] 0xE6 0x0F      AND,$0F
[0x0000031B] 0xFE 0x0F      CP,$0F
[0x0000031D] 0x20 0x1B      JR NZ,$1B
[0x0000031F] 0xF0 0xB1      LDH A,($B1)
[0x00000321] 0xA7           AND A
[0x00000322] 0xCA 0xE8 0x01 JP Z,$01E8
[0x00000325] 0xCF           RST 08H
[0x00000326] 0xCF           RST 08H
[0x00000327] 0xAF           XOR A
[0x00000328] 0xE0 0xCC      LDH ($CC),A
[0x0000032A] 0x3E 0xF0      LD A,$F0
[0x0000032C] 0xE0 0x01      LDH ($01),A
[0x0000032E] 0x3E 0x81      LD A,$81
[0x00000330] 0xE0 0x02      LDH ($02),A
[0x00000332] 0xF0 0xCC      LDH A,($CC)
[0x00000334] 0xA7           AND A
[0x00000335] 0x28 0xFB      JR Z,$FB
[0x00000337] 0xC3 0xE8 0x01 JP,$01E8
[0x0000033A] 0x21 0xA6 0xFF LD HL,$FFA6
[0x0000033D] 0x06 0x02      LD B,$02
[0x0000033F] 0x7E           LD A,(HL)
[0x00000340] 0xA7           AND A
[0x00000341] 0x28 0x01      JR Z,$01
[0x00000343] 0x35           DEC (HL)
[0x00000344] 0x2C           INC L
[0x00000345] 0x05           DEC B
[0x00000346] 0x20 0xF7      JR NZ,$F7
[0x00000348] 0x21 0xE2 0xFF LD HL,$FFE2
[0x0000034B] 0x34           INC (HL)
[0x0000034C] 0x21 0xE5 0xFF LD HL,$FFE5
[0x0000034F] 0x34           INC (HL)
[0x00000350] 0x21 0xE6 0xFF LD HL,$FFE6
[0x00000353] 0x34           INC (HL)
[0x00000354] 0x21 0xE7 0xFF LD HL,$FFE7
[0x00000357] 0x34           INC (HL)
[0x00000358] 0x76           HALT
[0x00000359] 0xF0 0x85      LDH A,($85)
[0x0000035B] 0xA7           AND A
[0x0000035C] 0x28 0xFA      JR Z,$FA
[0x0000035E] 0xAF           XOR A
[0x0000035F] 0xE0 0x85      LDH ($85),A
[0x00000361] 0xC3 0xA8 0x02 JP,$02A8
[0x00000364] 0xF0 0xDC      LDH A,($DC)
[0x00000366] 0xA7           AND A
[0x00000367] 0x20 0x3A      JR NZ,$3A
[0x00000369] 0xF0 0xD0      LDH A,($D0)
[0x0000036B] 0xFE 0xFD      CP,$FD
[0x0000036D] 0x28 0x0A      JR Z,$0A
[0x0000036F] 0xFE 0xF8      CP,$F8
[0x00000371] 0x28 0x21      JR Z,$21
[0x00000373] 0xFE 0x55      CP,$55
[0x00000375] 0xD0           RET NC
[0x00000376] 0xE0 0xD3      LDH ($D3),A
[0x00000378] 0xC9           RET
[0x00000379] 0xAF           XOR A
[0x0000037A] 0xE0 0xD0      LDH ($D0),A
[0x0000037C] 0x3E 0xF8      LD A,$F8
[0x0000037E] 0xE0 0xF4      LDH ($F4),A
[0x00000380] 0x06 0x17      LD B,$17
[0x00000382] 0xF0 0xB1      LDH A,($B1)
[0x00000384] 0xA7           AND A
[0x00000385] 0x20 0x05      JR NZ,$05
[0x00000387] 0x3E 0x01      LD A,$01
[0x00000389] 0xE0 0xA9      LDH ($A9),A
[0x0000038B] 0xC9           RET
[0x0000038C] 0x3E 0x10      LD A,$10
[0x0000038E] 0xE0 0xA6      LDH ($A6),A
[0x00000390] 0x78           LD A,B
[0x00000391] 0xE0 0xE1      LDH ($E1),A
[0x00000393] 0xC9           RET
[0x00000394] 0x3E 0xFD      LD A,$FD
[0x00000396] 0xE0 0xF4      LDH ($F4),A
[0x00000398] 0x06 0x0F      LD B,$0F
[0x0000039A] 0xF0 0xB1      LDH A,($B1)
[0x0000039C] 0xA7           AND A
[0x0000039D] 0x28 0xED      JR Z,$ED
[0x0000039F] 0x06 0x17      LD B,$17
[0x000003A1] 0x18 0xE9      JR,$E9
[0x000003A3] 0xFA 0xA4 0xC0 LD A,($C0A4)
[0x000003A6] 0xA7           AND A
[0x000003A7] 0xC8           RET Z
[0x000003A8] 0xFE 0xE0      CP,$E0
[0x000003AA] 0xC8           RET Z
[0x000003AB] 0x47           LD B,A
[0x000003AC] 0x78           LD A,B
[0x000003AD] 0xE6 0xC0      AND,$C0
[0x000003AF] 0x20 0x06      JR NZ,$06
[0x000003B1] 0xCB 0x20      SLA B
[0x000003B3] 0xCB 0x20      SLA B
[0x000003B5] 0x18 0xF5      JR,$F5
[0x000003B7] 0x48           LD C,B
[0x000003B8] 0xF0 0xD9      LDH A,($D9)
[0x000003BA] 0x57           LD D,A
[0x000003BB] 0x7A           LD A,D
[0x000003BC] 0xE6 0xC0      AND,$C0
[0x000003BE] 0x20 0x11      JR NZ,$11
[0x000003C0] 0x79           LD A,C
[0x000003C1] 0xE6 0xC0      AND,$C0
[0x000003C3] 0x28 0x19      JR Z,$19
[0x000003C5] 0xCB 0x21      SLA C
[0x000003C7] 0xCB 0x12      RL D
[0x000003C9] 0xCB 0x21      SLA C
[0x000003CB] 0xCB 0x12      RL D
[0x000003CD] 0x79           LD A,C
[0x000003CE] 0xA7           AND A
[0x000003CF] 0x20 0xEA      JR NZ,$the Big N
[0x000003D1] 0x7A           LD A,D
[0x000003D1] 0x7A           LD A,D
[0x000003D2] 0xE0 0xD9      LDH ($D9),A
[0x000003D4] 0xEA 0x16 0xD0 LD ($D016),A
[0x000003D7] 0xAF           XOR A
[0x000003D8] 0xE0 0xDC      LDH ($DC),A
[0x000003DA] 0xEA 0xA4 0xC0 LD ($C0A4),A
[0x000003DD] 0xC9           RET
[0x000003DE] 0xCB 0x21      SLA C
[0x000003E0] 0xCB 0x21      SLA C
[0x000003E2] 0x18 0xDC      JR,$DC
[0x000003E4] 0x11 0x08 0xD0 LD DE,$D008
[0x000003E7] 0x21 0xDD 0xFF LD HL,$FFDD
[0x000003EA] 0x7E           LD A,(HL)
[0x000003EB] 0xFE 0x02      CP,$02
[0x000003ED] 0x28 0x27      JR Z,$27
[0x000003EF] 0xFE 0x01      CP,$01
[0x000003F1] 0x28 0x16      JR Z,$16
[0x000003F3] 0x1A           LD A,(DE)
[0x000003F4] 0xA7           AND A
[0x000003F5] 0xC0           RET NZ
[0x000003F6] 0xFA 0x0E 0xD0 LD A,($D00E)
[0x000003F9] 0xA7           AND A
[0x000003FA] 0x20 0x04      JR NZ,$04
[0x000003FC] 0xF0 0xD1      LDH A,($D1)
[0x000003FE] 0x18 0x03      JR,$03
[0x00000400] 0xFA 0x46 0xD0 LD A,($D046)
[0x00000403] 0xE0 0xCF      LDH ($CF),A
[0x00000405] 0x1A           LD A,(DE)
[0x00000406] 0x3C           INC A
[0x00000407] 0x12           LD (DE),A
[0x00000408] 0xC9           RET
[0x00000409] 0x1A           LD A,(DE)
[0x0000040A] 0xA7           AND A
[0x0000040B] 0xC0           RET NZ
[0x0000040C] 0x3E 0xFE      LD A,$FE
[0x0000040E] 0xE0 0xCF      LDH ($CF),A
[0x00000410] 0x1A           LD A,(DE)
[0x00000411] 0x3C           INC A
[0x00000412] 0x12           LD (DE),A
[0x00000413] 0x36 0x02      LD (HL),$02
[0x00000415] 0xC9           RET
[0x00000416] 0x1A           LD A,(DE)
[0x00000417] 0xA7           AND A
[0x00000418] 0xC0           RET NZ
[0x00000419] 0xF0 0xD8      LDH A,($D8)
[0x0000041B] 0xE0 0xCF      LDH ($CF),A
[0x0000041D] 0xEA 0x46 0xD0 LD ($D046),A
[0x00000420] 0xAF           XOR A
[0x00000421] 0xE0 0xD8      LDH ($D8),A
[0x00000423] 0x77           LD (HL),A
[0x00000424] 0x3C           INC A
[0x00000425] 0x12           LD (DE),A
[0x00000426] 0xF0 0xCB      LDH A,($CB)
[0x00000428] 0xFE 0x60      CP,$60
[0x0000042A] 0x3E 0x0B      LD A,$0B
[0x0000042C] 0x28 0x02      JR Z,$02
[0x0000042E] 0x3E 0x08      LD A,$08
[0x00000430] 0xEA 0xE0 0xDF LD ($DFE0),A
[0x00000433] 0xC9           RET
[0x00000434] 0xFA 0x3A 0xD0 LD A,($D03A)
[0x00000437] 0xA7           AND A
[0x00000438] 0xC0           RET NZ
[0x00000439] 0xF0 0xCB      LDH A,($CB)
[0x0000043B] 0xFE 0x30      CP,$30
[0x0000043D] 0xC0           RET NZ
[0x0000043E] 0xF0 0xCF      LDH A,($CF)
[0x00000440] 0xE0 0x01      LDH ($01),A
[0x00000442] 0xCD 0x53 0x01 CALL,$0153
[0x00000445] 0xAF           XOR A
[0x00000446] 0xEA 0x08 0xD0 LD ($D008),A
[0x00000449] 0xFA 0xF1 0xC4 LD A,($C4F1)
[0x0000044C] 0xA7           AND A
[0x0000044D] 0x20 0x01      JR NZ,$01
[0x0000044F] 0xCF           RST 08H
[0x00000450] 0x3E 0x81      LD A,$81
[0x00000452] 0xE0 0x02      LDH ($02),A
[0x00000454] 0xC9           RET
[0x00000455] 0xF0 0xE1      LDH A,($E1)
[0x00000457] 0xEF           RST 28H
[0x00000458] 0x92           SUB D
[0x00000459] 0x04           INC B
[0x0000045A] 0xDA 0x04 0x8F JP C,$8F04
[0x0000045D] 0x0B           DEC BC
[0x0000045E] 0xC6 0x2F      ADD A,$2F
[0x00000460] 0xB4           OR H
[0x00000461] 0x0E 0xC8      LD C,$C8
[0x00000463] 0x0F           RRCA
[0x00000464] 0x39           ADD HL,SP
[0x00000465] 0x11 0xF4 0x14 LD DE,$14F4
[0x00000468] 0x90           SUB B
[0x00000469] 0x15           DEC D
[0x0000046A] 0xE8 0x0B      ADD SP,$0B
[0x0000046C] 0x6F           LD L,A
[0x0000046D] 0x33           INC SP
[0x0000046E] 0x88           ADC A,B
[0x0000046F] 0x05           DEC B
[0x00000470] 0x79           LD A,C
[0x00000471] 0x06 0x48      LD B,$48
[0x00000473] 0x08 0xD6 0x09 LD ($09D6),SP
[0x00000476] 0xF5           PUSH AF
[0x00000477] 0x12           LD (DE),A
[0x00000478] 0xB8           CP B
[0x00000479] 0x13           INC DE
[0x0000047A] 0x32           LD (HL-),A
[0x0000047B] 0x14           INC D
[0x0000047C] 0xFB           EI
[0x0000047D] 0x20 0x01      JR NZ,$01
[0x0000047F] 0x16 0x9B      LD D,$9B
[0x00000480] 0x9B           SBC A,E
[0x00000481] 0x05           DEC B
[0x00000482] 0xAF           XOR A
[0x00000483] 0x21 0xEB 0x0D LD HL,$0DEB
[0x00000486] 0xAB           XOR E
[0x00000487] 0x12           LD (DE),A
[0x00000488] 0x74           LD (HL),H
[0x00000489] 0x16 0x58      LD D,$58
[0x0000048B] 0x32           LD (HL-),A
[0x0000048C] 0xE8 0x16      ADD SP,$16
[0x0000048E] 0xA3           AND E
[0x0000048F] 0x14           INC D
[0x00000490] 0xC8           RET Z
[0x00000491] 0x20 0xCD      JR NZ,$CD
[0x00000493] 0x50           LD D,B
[0x00000494] 0x22           LD (HL+),A
[0x00000495] 0xCD 0x40 0x1E CALL,$1E40
[0x00000498] 0x11 0x26 0x5C LD DE,$5C26
[0x0000049B] 0xCD 0xC9 0x20 CALL,$20C9
[0x0000049E] 0x3E 0x83      LD A,$83
[0x000004A0] 0xE0 0x40      LDH ($40),A
[0x000004A2] 0xAF           XOR A
[0x000004A3] 0xEA 0x3A 0xD0 LD ($D03A),A
[0x000004A6] 0xE0 0x01      LDH ($01),A
[0x000004A8] 0xE0 0xCF      LDH ($CF),A
[0x000004AA] 0xE0 0xD0      LDH ($D0),A
[0x000004AC] 0xE0 0xF2      LDH ($F2),A
[0x000004AE] 0xE0 0xB1      LDH ($B1),A
[0x000004B0] 0xEA 0xF1 0xC4 LD ($C4F1),A
[0x000004B3] 0x3C           INC A
[0x000004B4] 0xE0 0xE1      LDH ($E1),A
[0x000004B6] 0xE0 0xE4      LDH ($E4),A
[0x000004B8] 0x21 0x00 0xC0 LD HL,$C000
[0x000004BB] 0x36 0x70      LD (HL),$70
[0x000004BD] 0x2C           INC L
[0x000004BE] 0x36 0x20      LD (HL),$20
[0x000004C0] 0x2C           INC L
[0x000004C1] 0x36 0x9B      LD (HL),$9B
[0x000004C3] 0x3E 0x03      LD A,$03
[0x000004C5] 0xE0 0xAD      LDH ($AD),A
[0x000004C7] 0xE0 0xAE      LDH ($AE),A
[0x000004C9] 0x3E 0x02      LD A,$02
[0x000004CB] 0xE0 0xF0      LDH ($F0),A
[0x000004CD] 0x3E 0xFF      LD A,$FF
[0x000004CF] 0xE0 0xA6      LDH ($A6),A
[0x000004D1] 0x3E 0x01      LD A,$01
[0x000004D3] 0xEA 0x54 0xD0 LD ($D054),A
[0x000004D6] 0xEA 0xE0 0xDF LD ($DFE0),A
[0x000004D9] 0xC9           RET
[0x00001E40] 0x21 0x00 0xC0 LD HL,$C000
[0x00001E43] 0x06 0xA0      LD B,$A0
[0x00001E45] 0xAF           XOR A
[0x00001E46] 0x22           LD (HL+),A
[0x00001E47] 0x05           DEC B
[0x00001E48] 0x20 0xFC      JR NZ,$FC
[0x00001E4A] 0xC9           RET
[0x000020A3] 0x21 0xFF 0x9B LD HL,$9BFF
[0x000020A6] 0x01 0x00 0x04 LD BC,$0400
[0x000020A9] 0x3E 0xFF      LD A,$FF
[0x000020AB] 0x32           LD (HL-),A
[0x000020AC] 0x0B           DEC BC
[0x000020AD] 0x78           LD A,B
[0x000020AE] 0xB1           OR C
[0x000020AF] 0x20 0xF8      JR NZ,$F8
[0x000020B1] 0xC9           RET
[0x000020B2] 0x2A           LD A,(HL+)
[0x000020B3] 0x12           LD (DE),A
[0x000020B4] 0x13           INC DE
[0x000020B5] 0x0B           DEC BC
[0x000020B6] 0x78           LD A,B
[0x000020B7] 0xB1           OR C
[0x000020B8] 0x20 0xF8      JR NZ,$F8
[0x000020BA] 0xC9           RET
[0x000020BB] 0x21 0x9E 0x3D LD HL,$3D9E
[0x000020BE] 0x11 0x00 0x80 LD DE,$8000
[0x000020C1] 0x01 0xFF 0x17 LD BC,$17FF
[0x000020C4] 0xCD 0xB2 0x20 CALL,$20B2
[0x000020C7] 0xC9           RET
[0x000020C9] 0x21 0x00 0x98 LD HL,$9800
[0x000020CC] 0x06 0x12      LD B,$12
[0x000020CE] 0xE5           PUSH HL
[0x000020CF] 0x0E 0x14      LD C,$14
[0x000020D1] 0x1A           LD A,(DE)
[0x000020D2] 0x22           LD (HL+),A
[0x000020D3] 0x13           INC DE
[0x000020D4] 0x0D           DEC C
[0x000020D5] 0x20 0xFA      JR NZ,$FA
[0x000020D7] 0xE1           POP HL
[0x000020D8] 0xD5           PUSH DE
[0x000020D9] 0x11 0x20 0x00 LD DE,$0020
[0x000020DC] 0x19           ADD HL,DE
[0x000020DD] 0xD1           POP DE
[0x000020DE] 0x05           DEC B
[0x000020DF] 0x20 0xED      JR NZ,$ED
[0x000020E1] 0xC9           RET
[0x0000231C] 0x3E 0x20      LD A,$20
[0x0000231E] 0xE0 0x00      LDH ($00),A
[0x00002320] 0xF0 0x00      LDH A,($00)
[0x00002322] 0xF0 0x00      LDH A,($00)
[0x00002324] 0xF0 0x00      LDH A,($00)
[0x00002326] 0xF0 0x00      LDH A,($00)
[0x00002328] 0x2F           CPL
[0x00002329] 0xE6 0x0F      AND,$0F
[0x0000232B] 0xCB 0x37      SWAP A
[0x0000232D] 0x47           LD B,A
[0x0000232E] 0x3E 0x10      LD A,$10
[0x00002330] 0xE0 0x00      LDH ($00),A
[0x00002332] 0xF0 0x00      LDH A,($00)
[0x00002334] 0xF0 0x00      LDH A,($00)
[0x00002336] 0xF0 0x00      LDH A,($00)
[0x00002338] 0xF0 0x00      LDH A,($00)
[0x0000233A] 0xF0 0x00      LDH A,($00)
[0x0000233C] 0xF0 0x00      LDH A,($00)
[0x0000233E] 0xF0 0x00      LDH A,($00)
[0x00002340] 0xF0 0x00      LDH A,($00)
[0x00002342] 0xF0 0x00      LDH A,($00)
[0x00002344] 0xF0 0x00      LDH A,($00)
[0x00002346] 0x2F           CPL
[0x00002347] 0xE6 0x0F      AND,$0F
[0x00002349] 0xB0           OR B
[0x0000234A] 0x4F           LD C,A
[0x0000234B] 0xF0 0x80      LDH A,($80)
[0x0000234D] 0xA9           XOR C
[0x0000234E] 0xA1           AND C
[0x0000234F] 0xE0 0x81      LDH ($81),A
[0x00002351] 0x79           LD A,C
[0x00002352] 0xE0 0x80      LDH ($80),A
[0x00002354] 0x3E 0x30      LD A,$30
[0x00002356] 0xE0 0x00      LDH ($00),A
[0x00002358] 0xC9           RET
[0x00003002] 0xF0 0xE4      LDH A,($E4)
[0x00003004] 0xA7           AND A
[0x00003005] 0x20 0x0C      JR NZ,$0C
[0x00003007] 0x06 0x01      LD B,$01
[0x00003009] 0xF0 0xC1      LDH A,($C1)
[0x0000300B] 0xA7           AND A
[0x0000300C] 0x28 0x0B      JR Z,$0B
[0x0000300E] 0x04           INC B
[0x0000300F] 0xFE 0x01      CP,$01
[0x00003011] 0x28 0x06      JR Z,$06
[0x00003013] 0x3E 0x07      LD A,$07
[0x00003013] 0x3E 0x07      LD A,$07
[0x00003015] 0xEA 0xE8 0xDF LD ($DFE8),A
[0x00003018] 0xC9           RET
[0x00003019] 0x78           LD A,B
[0x0000301A] 0xEA 0xE8 0xDF LD ($DFE8),A
[0x0000301D] 0xC9           RET
[0x00006507] 0x3E 0xFF      LD A,$FF
[0x00006509] 0xE0 0x25      LDH ($25),A
[0x0000650B] 0x3E 0x03      LD A,$03
[0x0000650D] 0xEA 0x78 0xDF LD ($DF78),A
[0x00006510] 0xAF           XOR A
[0x00006511] 0xEA 0xE9 0xDF LD ($DFE9),A
[0x00006514] 0xAF           XOR A
[0x00006515] 0xEA 0xE1 0xDF LD ($DFE1),A
[0x00006518] 0xEA 0xF1 0xDF LD ($DFF1),A
[0x0000651B] 0xEA 0xF9 0xDF LD ($DFF9),A
[0x0000651E] 0xEA 0x9F 0xDF LD ($DF9F),A
[0x00006521] 0xEA 0xAF 0xDF LD ($DFAF),A
[0x00006524] 0xEA 0xBF 0xDF LD ($DFBF),A
[0x00006527] 0xEA 0xCF 0xDF LD ($DFCF),A
[0x0000652A] 0xEA 0x7E 0xDF LD ($DF7E),A
[0x0000652D] 0xEA 0x7F 0xDF LD ($DF7F),A
[0x00006530] 0xEA 0x8F 0xDF LD ($DF8F),A
[0x00006533] 0xEA 0x8D 0xDF LD ($DF8D),A
[0x00006536] 0xEA 0x8E 0xDF LD ($DF8E),A
[0x00006539] 0xEA 0x8A 0xDF LD ($DF8A),A
[0x0000653C] 0xEA 0x8B 0xDF LD ($DF8B),A
[0x0000653F] 0x3E 0x08      LD A,$08
[0x00006541] 0xE0 0x12      LDH ($12),A
[0x00006543] 0xE0 0x17      LDH ($17),A
[0x00006545] 0xE0 0x21      LDH ($21),A
[0x00006547] 0x3E 0x80      LD A,$80
[0x00006549] 0xE0 0x14      LDH ($14),A
[0x0000654B] 0xE0 0x19      LDH ($19),A
[0x0000654D] 0xE0 0x23      LDH ($23),A
[0x0000654F] 0xAF           XOR A
[0x00006550] 0xE0 0x10      LDH ($10),A
[0x00006552] 0xE0 0x1A      LDH ($1A),A
[0x00006554] 0xC9           RET
[0x00007FF3] 0xC3 0x07 0x65 JP,$6507

Last edited by mjm (2013-02-20 17:29:01)

paulc · 2013-02-19 01:23:36

"- MBC1 - adresses 0x0000-0x3FFF are mapped directly to offset in ROM, adresses 0x4000-0x7FFF are mapped to (bank*0x4000)+addr in ROM image. Is this OK?
3. Are there any "original" ROMs dis-assemblies I can test on? I have found only Pokemon, but it's to complex to be analyzed. I'm looking for something simpler, preferably 32KB ROM or MBC1."

Your 2nd question seems right. If an address is in bank 02, at location 4000, an appropriate term would be "02:4000" or "02x4000" as you have.

Your 3rd question.... I think the best and easiest way would be to create a simple test rom with ASM, then disassemble that ROM. This would allow you to add increasing complexity to see how your program handles disassembling it. I'd recommend against disassembling GBDK games though, as I've disassembled my own GBDK creation and found all kinds of junk code. You could probably find some homebrew made in ASM with the source available to compare to.

Last edited by paulc (2013-02-19 01:24:24)

mjm · 2013-02-19 06:01:48

2. For example in Super Mario Land I have:

Code:

[0x0000020D] 0x3E 0x03      LD A,$03
[0x0000020F] 0xEA 0x00 0x20 LD ($2000),A

This means change to memory bank 3.
edit: rephrasing the question
PC (Program Counter) and call/jump addresses
0x0000-0x3FFF -> physically still mapped to 0x0000-0x3FFF
0x4000-0x7FFF -> physically remapped to 0xC000-0xFFFF, am I right?

3. As I said before, I've already disassembled some home-brew games correctly, but I am looking for something "original".

Last edited by mjm (2013-02-19 06:21:05)

paulc · 2013-02-19 15:13:53

The additional banks are always in #x4000-7FFF.
So 0x4000, 1x4000, 2x4000, 3x4000, etc.
$C000 is WRAM then you're going up into hardware registers. So pretty sure that's not it.

Sorry, I didn't see anything in your post about that you've already tried disassembling homebrew.

nitro2k01 · 2013-02-20 09:45:43

paulc wrote:
So 0x4000, 1x4000, 2x4000, 3x4000, etc.

That's a novel, but incorrect way of writing the addresses. 0x is the hexadecimal prefix in C and related languages, and there's no such notation as 1x, 2x etc for different banks. no$gmb and later BGB are using a colon notation, like 01:4000.

Duo · 2013-02-20 12:22:38

I think you'll be better off thinking about the ROM in terms of banks rather than a linear chunk.

0x4000 x (in SML case) 4 banks

00:0000-3FFF on GB - 0000-3FFF in file
01:4000-7FFF on GB - 4000-7FFF in file
02:4000-7FFF on GB - 8000-BFFF in file
03:4000-7FFF on GB - C000-FFFF in file

etc for larger ROM images.

The hard part in a disassembler is that knowing which ROM bank a CALL is going to in isn't always clear from the routines, as the bank switch may be done in a prior routine. There are quite a few games that have JP XXXX at 0x4000, 0x4003, 0x4006 etc that point to code elsewhere in the bank, but every bank has those JPs at the beginning, so you end up with a CALL 0x4000 that can be valid in a dozen banks, and a single CALL 0x4000 in Bank 0 that is used for calling routines in many different banks.

For your disassembler to be useful, it should maintain a database of references that can be manually tagged to specific banks, or have the user manually enter it into a comment field for that particular opcode line.

mjm · 2013-02-20 17:26:31

At the moment I can't even disassemble correctly Tetris so I will think about banks switching later
I use Testris ROM (MD5: 982ed5d2b12a0377eb14bcdc4123744e) and as reference the BGB emulator (it has an option to dump the asm code). It's a 32KB ROM without any MBC. My disassembly starts failing at instruction:
[0x000002A0] 0xCD 0x95 0x27 CALL,$2795
Disassembly after following the call is totally different than that produced by BGB. Before everything is OK.

I've put the results of my battle against the GameBoy on github:
https://github.com/mmuszkow/gb-disasm
Code is written in pure C, big part of it is auto-generated. Binary of Windows version is not up to date (I have only access to Linux right now), I will update it tomorrow.

Testris disassembly:

Code:

[0x00000100] 0x00           NOP
[0x00000101] 0xC3 0x50 0x01 JP,$0150
[0x00000150] 0xC3 0x0C 0x02 JP,$020C
[0x0000020C] 0xAF           XOR A
[0x0000020D] 0x21 0xFF 0xDF LD HL,$DFFF
[0x00000210] 0x0E 0x10      LD C,$10
[0x00000212] 0x06 0x00      LD B,$00
[0x00000214] 0x32           LD (HL-),A
[0x00000215] 0x05           DEC B
[0x00000216] 0x20 0xFC      JR NZ,$FC ; 0x214
[0x00000218] 0x0D           DEC C
[0x00000219] 0x20 0xF9      JR NZ,$F9 ; 0x214
[0x0000021B] 0x3E 0x01      LD A,$01
[0x0000021D] 0xF3           DI
[0x0000021E] 0xE0 0x0F      LDH ($0F),A
[0x00000220] 0xE0 0xFF      LDH ($FF),A
[0x00000222] 0xAF           XOR A
[0x00000223] 0xE0 0x42      LDH ($42),A
[0x00000225] 0xE0 0x43      LDH ($43),A
[0x00000227] 0xE0 0xA4      LDH ($A4),A
[0x00000229] 0xE0 0x41      LDH ($41),A
[0x0000022B] 0xE0 0x01      LDH ($01),A
[0x0000022D] 0xE0 0x02      LDH ($02),A
[0x0000022F] 0x3E 0x80      LD A,$80
[0x00000231] 0xE0 0x40      LDH ($40),A
[0x00000233] 0xF0 0x44      LDH A,($44)
[0x00000235] 0xFE 0x94      CP,$94
[0x00000237] 0x20 0xFA      JR NZ,$FA ; 0x233
[0x00000239] 0x3E 0x03      LD A,$03
[0x0000023B] 0xE0 0x40      LDH ($40),A
[0x0000023D] 0x3E 0xE4      LD A,$E4
[0x0000023F] 0xE0 0x47      LDH ($47),A
[0x00000241] 0xE0 0x48      LDH ($48),A
[0x00000243] 0x3E 0xC4      LD A,$C4
[0x00000245] 0xE0 0x49      LDH ($49),A
[0x00000247] 0x21 0x26 0xFF LD HL,$FF26
[0x0000024A] 0x3E 0x80      LD A,$80
[0x0000024C] 0x32           LD (HL-),A
[0x0000024D] 0x3E 0xFF      LD A,$FF
[0x0000024F] 0x32           LD (HL-),A
[0x00000250] 0x36 0x77      LD (HL),$77
[0x00000252] 0x3E 0x01      LD A,$01
[0x00000254] 0xEA 0x00 0x20 LD ($2000),A
[0x00000257] 0x31 0xFF 0xCF LD SP,$CFFF
[0x0000025A] 0xAF           XOR A
[0x0000025B] 0x21 0xFF 0xDF LD HL,$DFFF
[0x0000025E] 0x06 0x00      LD B,$00
[0x00000260] 0x32           LD (HL-),A
[0x00000261] 0x05           DEC B
[0x00000262] 0x20 0xFC      JR NZ,$FC ; 0x260
[0x00000264] 0x21 0xFF 0xCF LD HL,$CFFF
[0x00000267] 0x0E 0x10      LD C,$10
[0x00000269] 0x06 0x00      LD B,$00
[0x0000026B] 0x32           LD (HL-),A
[0x0000026C] 0x05           DEC B
[0x0000026D] 0x20 0xFC      JR NZ,$FC ; 0x26B
[0x0000026F] 0x0D           DEC C
[0x00000270] 0x20 0xF9      JR NZ,$F9 ; 0x26B
[0x00000272] 0x21 0xFF 0x9F LD HL,$9FFF
[0x00000275] 0x0E 0x20      LD C,$20
[0x00000277] 0xAF           XOR A
[0x00000278] 0x06 0x00      LD B,$00
[0x0000027A] 0x32           LD (HL-),A
[0x0000027B] 0x05           DEC B
[0x0000027C] 0x20 0xFC      JR NZ,$FC ; 0x27A
[0x0000027E] 0x0D           DEC C
[0x0000027F] 0x20 0xF9      JR NZ,$F9 ; 0x27A
[0x00000281] 0x21 0xFF 0xFE LD HL,$FEFF
[0x00000284] 0x06 0x00      LD B,$00
[0x00000286] 0x32           LD (HL-),A
[0x00000287] 0x05           DEC B
[0x00000288] 0x20 0xFC      JR NZ,$FC ; 0x286
[0x0000028A] 0x21 0xFE 0xFF LD HL,$FFFE
[0x0000028D] 0x06 0x80      LD B,$80
[0x0000028F] 0x32           LD (HL-),A
[0x00000290] 0x05           DEC B
[0x00000291] 0x20 0xFC      JR NZ,$FC ; 0x28F
[0x00000293] 0x0E 0xB6      LD C,$B6
[0x00000295] 0x06 0x0C      LD B,$0C
[0x00000297] 0x21 0x7F 0x2A LD HL,$2A7F
[0x0000029A] 0x2A           LD A,(HL+)
[0x0000029B] 0xE2           LD (C),A
[0x0000029C] 0x0C           INC C
[0x0000029D] 0x05           DEC B
[0x0000029E] 0x20 0xFA      JR NZ,$FA ; 0x29A
[0x000002A0] 0xCD 0x95 0x27 CALL,$2795
[0x000002A3] 0xCD 0xF3 0x7F CALL,$7FF3
[0x000002A6] 0x3E 0x09      LD A,$09
[0x000002A8] 0xE0 0xFF      LDH ($FF),A
[0x000002AA] 0x3E 0x37      LD A,$37
[0x000002AC] 0xE0 0xC0      LDH ($C0),A
[0x000002AE] 0x3E 0x1C      LD A,$1C
[0x000002B0] 0xE0 0xC1      LDH ($C1),A
[0x000002B2] 0x3E 0x24      LD A,$24
[0x000002B4] 0xE0 0xE1      LDH ($E1),A
[0x000002B6] 0x3E 0x80      LD A,$80
[0x000002B8] 0xE0 0x40      LDH ($40),A
[0x000002BA] 0xFB           EI
[0x000002BB] 0xAF           XOR A
[0x000002BC] 0xE0 0x0F      LDH ($0F),A
[0x000002BE] 0xE0 0x4A      LDH ($4A),A
[0x000002C0] 0xE0 0x4B      LDH ($4B),A
[0x000002C2] 0xE0 0x06      LDH ($06),A
[0x000002C4] 0xCD 0xA6 0x29 CALL,$29A6
[0x000002C7] 0xCD 0xF8 0x02 CALL,$02F8
[0x000002F8] 0xF0 0xE1      LDH A,($E1)
[0x000002FA] 0xEF           RST 28H
[0x000002FB] 0xCE 0x1B      ADC A,$1B
[0x000002FD] 0xE2           LD (C),A
[0x000002FE] 0x1C           INC E
[0x000002FF] 0x44           LD B,H
[0x00000300] 0x12           LD (DE),A
[0x00000301] 0x7B           LD A,E
[0x00000302] 0x12           LD (DE),A
[0x00000303] 0x06 0x1D      LD B,$1D
[0x00000305] 0x26 0x1D      LD H,$1D
[0x00000307] 0xAE           XOR (HL)
[0x00000308] 0x03           INC BC
[0x00000309] 0x79           LD A,C
[0x0000030A] 0x04           INC B
[0x0000030B] 0x44           LD B,H
[0x0000030C] 0x14           INC D
[0x0000030D] 0x8C           ADC A,H
[0x0000030E] 0x14           INC D
[0x0000030F] 0x07           RLCA
[0x00000310] 0x1A           LD A,(DE)
[0x00000311] 0xC0           RET NZ
[0x00000312] 0x1D           DEC E
[0x00000313] 0x16 0x1F      LD D,$1F
[0x00000315] 0x1F           RRA
[0x00000316] 0x1F           RRA
[0x00000317] 0x25           DEC H
[0x00000318] 0x15           DEC D
[0x00000319] 0xB0           OR B
[0x0000031A] 0x14           INC D
[0x0000031B] 0x7B           LD A,E
[0x0000031C] 0x15           DEC D
[0x0000031D] 0xBF           CP A
[0x0000031E] 0x15           DEC D
[0x0000031F] 0x29           ADD HL,HL
[0x00000320] 0x16 0x7A      LD D,$7A
[0x00000322] 0x16 0xEB      LD D,$EB
[0x00000324] 0x16 0x13      LD D,$13
[0x00000326] 0x19           ADD HL,DE
[0x00000327] 0x77           LD (HL),A
[0x00000328] 0x06 0x2C      LD B,$2C
[0x0000032A] 0x07           RLCA
[0x0000032B] 0x25           DEC H
[0x0000032C] 0x08 0xE4 0x08 LD ($08E4),SP
[0x0000032F] 0x31 0x0B 0xEB LD SP,$EB0B
[0x00000332] 0x0C           INC C
[0x00000333] 0xD2 0x0A 0x32 JP NC,$320A
[0x00000336] 0x0D           DEC C
[0x00000337] 0x23           INC HL
[0x00000338] 0x0E 0x12      LD C,$12
[0x0000033A] 0x11 0x99 0x0D LD DE,$0D99
[0x0000033D] 0x8A           ADC A,D
[0x0000033E] 0x0E 0xCE      LD C,$CE
[0x00000340] 0x1D           DEC E
[0x00000341] 0x41           LD B,C
[0x00000342] 0x1E 0x69      LD E,$69
[0x00000344] 0x03           INC BC
[0x00000345] 0x93           SUB E
[0x00000346] 0x03           INC BC
[0x00000347] 0x67           LD H,A
[0x00000348] 0x11 0xE6 0x11 LD DE,$11E6
[0x00002795] 0x21 0xFF 0x9B LD HL,$9BFF
[0x00002798] 0x01 0x00 0x04 LD BC,$0400
[0x0000279B] 0x3E 0x2F      LD A,$2F
[0x0000279D] 0x32           LD (HL-),A
[0x0000279E] 0x0B           DEC BC
[0x0000279F] 0x78           LD A,B
[0x000027A0] 0xB1           OR C
[0x000027A1] 0x20 0xF8      JR NZ,$F8 ; 0x279B
[0x000027A3] 0xC9           RET
[0x000029A6] 0x3E 0x20      LD A,$20
[0x000029A8] 0xE0 0x00      LDH ($00),A
[0x000029AA] 0xF0 0x00      LDH A,($00)
[0x000029AC] 0xF0 0x00      LDH A,($00)
[0x000029AE] 0xF0 0x00      LDH A,($00)
[0x000029B0] 0xF0 0x00      LDH A,($00)
[0x000029B2] 0x2F           CPL
[0x000029B3] 0xE6 0x0F      AND,$0F
[0x000029B5] 0xCB 0x37      SWAP A
[0x000029B7] 0x47           LD B,A
[0x000029B8] 0x3E 0x10      LD A,$10
[0x000029BA] 0xE0 0x00      LDH ($00),A
[0x000029BC] 0xF0 0x00      LDH A,($00)
[0x000029BE] 0xF0 0x00      LDH A,($00)
[0x000029C0] 0xF0 0x00      LDH A,($00)
[0x000029C2] 0xF0 0x00      LDH A,($00)
[0x000029C4] 0xF0 0x00      LDH A,($00)
[0x000029C6] 0xF0 0x00      LDH A,($00)
[0x000029C8] 0xF0 0x00      LDH A,($00)
[0x000029CA] 0xF0 0x00      LDH A,($00)
[0x000029CC] 0xF0 0x00      LDH A,($00)
[0x000029CE] 0xF0 0x00      LDH A,($00)
[0x000029D0] 0x2F           CPL
[0x000029D1] 0xE6 0x0F      AND,$0F
[0x000029D3] 0xB0           OR B
[0x000029D4] 0x4F           LD C,A
[0x000029D5] 0xF0 0x80      LDH A,($80)
[0x000029D7] 0xA9           XOR C
[0x000029D8] 0xA1           AND C
[0x000029D9] 0xE0 0x81      LDH ($81),A
[0x000029DB] 0x79           LD A,C
[0x000029DC] 0xE0 0x80      LDH ($80),A
[0x000029DE] 0x3E 0x30      LD A,$30
[0x000029E0] 0xE0 0x00      LDH ($00),A
[0x000029E2] 0xC9           RET
[0x0000320C] 0x18 0x20      JR,$20 ; 0x322C
[0x0000322C] 0x18 0x00      JR,$00 ; 0x322C
[0x000069A5] 0xAF           XOR A
[0x000069A6] 0xEA 0xE1 0xDF LD ($DFE1),A
[0x000069A9] 0xEA 0xE9 0xDF LD ($DFE9),A
[0x000069AC] 0xEA 0xF1 0xDF LD ($DFF1),A
[0x000069AF] 0xEA 0xF9 0xDF LD ($DFF9),A
[0x000069B2] 0xEA 0x9F 0xDF LD ($DF9F),A
[0x000069B5] 0xEA 0xAF 0xDF LD ($DFAF),A
[0x000069B8] 0xEA 0xBF 0xDF LD ($DFBF),A
[0x000069BB] 0xEA 0xCF 0xDF LD ($DFCF),A
[0x000069BE] 0x3E 0xFF      LD A,$FF
[0x000069C0] 0xE0 0x25      LDH ($25),A
[0x000069C2] 0x3E 0x03      LD A,$03
[0x000069C4] 0xEA 0x78 0xDF LD ($DF78),A
[0x000069C7] 0x3E 0x08      LD A,$08
[0x000069C9] 0xE0 0x12      LDH ($12),A
[0x000069CB] 0xE0 0x17      LDH ($17),A
[0x000069CD] 0xE0 0x21      LDH ($21),A
[0x000069CF] 0x3E 0x80      LD A,$80
[0x000069D1] 0xE0 0x14      LDH ($14),A
[0x000069D3] 0xE0 0x19      LDH ($19),A
[0x000069D5] 0xE0 0x23      LDH ($23),A
[0x000069D7] 0xAF           XOR A
[0x000069D8] 0xE0 0x10      LDH ($10),A
[0x000069DA] 0xE0 0x1A      LDH ($1A),A
[0x000069DC] 0xC9           RET
[0x00007FF3] 0xC3 0xA5 0x69 JP,$69A5

Last edited by mjm (2013-02-20 17:29:42)

paulc · 2013-02-23 21:39:58

There's also a commercial release that has its source code available: Mr. Doh!
That might be a good one to compare to since, in theory, the ROM should match the source.

paulc · 2013-02-24 23:18:26

will this program be able to recognize the difference between code and data?

mjm · 2013-02-25 03:54:38

Yes, now by default it only prints code and with -a option whole assembly (however printing data content is not yet implemented).

Mr.Do! assembly was very useful to see how original games were written, thanks! Unfortunately it seems that ROM doesn't exactly match the source. I tried to convert the assembly to format acceptable by rgbasm to create ROM from that code, but gave up (rgbasm doesn't support for example ds 10, $A0 instruction).

Gameboy Development Forum

#1 2013-02-18 20:42:04

GB ROMs disassembler

Code:

#2 2013-02-19 01:23:36

Re: GB ROMs disassembler

#3 2013-02-19 06:01:48

Re: GB ROMs disassembler

Code:

#4 2013-02-19 15:13:53

Re: GB ROMs disassembler

#5 2013-02-20 09:45:43

Re: GB ROMs disassembler

paulc wrote:

#6 2013-02-20 12:22:38

Re: GB ROMs disassembler

#7 2013-02-20 17:26:31

Re: GB ROMs disassembler

Code:

#8 2013-02-23 21:39:58

Re: GB ROMs disassembler

#9 2013-02-24 23:18:26

Re: GB ROMs disassembler

#10 2013-02-25 03:54:38

Re: GB ROMs disassembler

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