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Forum Index : Microcontroller and PC projects : CHIP-8 disassembler for Maximite
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BobDevries Senior Member  Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Hi all, I know this programme probably has limited appeal, but hey, it kept me busy for a day, so I thought I'd post it here. Some of you may remember the DREAM 6800 SBC, which appeared in Electronics Australia in 1979. Its high level language was CHIP-8. Here's the code: START: Rem CHIP-8 Disassembler written in MMBASIC Rem Copyright (c) 2012 by Bob Devries Do Cls : Locate 40,150 : Print "CHIP-8 Disassembler (c) 2012 by Bob Devries" Locate 40,165 : Print Space$(70) Locate 40,165 Print "Please type CHIP-8 Binary filename (or ENTER to exit) "; Line Input fn$ If fn$ = "" Then Exit Open fn$ For input As #1 If MM.Errno <> 0 Then Print "Error opening input file." : Exit fo = Instr(1,fn$,".") If fo = 0 Then fo$ = fn$ + ".ch8" Else fo$ = Left$(fn$,fo-1) + ".ch8" EndIf Locate 40,180 : Print "Output to screen or file?" Locate 40,195 : Print "Press 'S' or 'F'" keyloop: k$ = Inkey$ : If k$ = "" Then GoTo keyloop k$ = UCase$(k$) If k$ <> "S" And k$ <> "F" GoTo keyloop If k$ = "S" Then dev = 0 Else dev = 2 If k$ = "F" Then Locate 40,210 : Print "Output filename will be ";fo$ If dev <> 0 Then Open fo$ For output As #dev EndIf If MM.Errno <> 0 Then Print "Error opening output file." : Exit Do While Not(Eof(#1)) w1 = Asc(Input$(1,#1)) w2 = Asc(Input$(1,#1)) word = w1 * 256 + w2 : Rem make it decimal whex$ = Hex$(word) : Rem make it hex whex$ = "000" + whex$ : Rem we want leading zeroes whex$ = Right$(whex$,4) : Rem but just 4 chars lhex = Val("&H" + Left$(whex$,1)) If lhex = 0 Then GoSub zero : GoTo cont If lhex = 1 Then GoSub one : GoTo cont If lhex = 2 Then GoSub two : GoTo cont If lhex = 3 Then GoSub three : GoTo cont If lhex = 4 Then GoSub four : GoTo cont If lhex = 5 Then GoSub five : GoTo cont If lhex = 6 Then GoSub six : GoTo cont If lhex = 7 Then GoSub seven : GoTo cont If lhex = 8 Then GoSub eight : GoTo cont If lhex = 9 Then GoSub nine : GoTo cont If lhex = 10 Then GoSub ten : GoTo cont If lhex = 11 Then GoSub eleven : GoTo cont If lhex = 12 Then GoSub twelve : GoTo cont If lhex = 13 Then GoSub thirteen : GoTo cont If lhex = 14 Then GoSub fourteen : GoTo cont If lhex = 15 Then GoSub fifteen : GoTo cont cont: Pause 100 Loop If dev = 2 Then Close #dev EndIf Close #1 Print "Files closed" Loop Cls : Locate 40,150 : Print "CHIP-8 Disassembler" Locate 40,165 : Print "End run. Goodbye!" End zero: Rem 0XXX If whex$ = "0000" Then Print #dev,whex$;" : NOP" : Return If whex$ = "00E0" Then Print #dev,whex$;" : ERASE" : Return If whex$ = "00EE" Then Print #dev,whex$;" : RETURN" : Return MMM$ = Right$(whex$,3) If Val("&H"+MMM$) < &H200 Then Print #dev,whex$;" : Unknown code" : Return EndIf Print #dev,whex$;" : CALL(M/C) $";MMM$ Return one: Rem 1MMM MMM$ = Right$(whex$,3) Print #dev,whex$;" : GOTO $";MMM$ Return two: Rem 2MMM MMM$ = Right$(whex$,3) Print #dev,whex$;" : DO $";MMM$ Return three: Rem 3XXX vx$ = Mid$(whex$,2,1) : kk$ = Right$(whex$,2) Print #dev,whex$;" : SKF V";vx$;" = $";kk$ Return four: Rem 4XXX vx$ = Mid$(whex$,2,1) : kk$ = Right$(whex$,2) Print #dev,whex$;" : SKF V";vx$;" <> $";kk$ Return five: Rem 5XXX vx$ = Mid$(whex$,2,1) : vy$ = Mid$(whex$,3,1) Print #dev,whex$;" : SKF V";vx$;" = V";vy$ Return six: Rem 6XKK vx$ = Mid$(whex$,2,1) : kk$ = Right$(whex$,2) Print #dev,whex$;" : V";vx$;" = $";kk$ Return seven: Rem 7XXX vx$ = Mid$(whex$,2,1) : kk$ = Right$(whex$,2) Print #dev,whex$;" : V";vx$;" = V";vx$;" + $";kk$ Return eight: Rem 8XXX act$ = Right$(whex$,1) vx$ = Mid$(whex$,2,1) : vy$ = Mid$(whex$,3,1) If act$ = "0" Then Print #dev,whex$;" : V";vx$;" = V";vy$ : Return EndIf If act$ = "1" Then Print #dev,whex$;" : V";vx$;" = V";vx$;" OR V";vy$ : Return EndIf If act$ = "2" Then Print #dev,whex$;" : V";vx$;" = V";vx$;" AND V";vy$ : Return EndIf If act$ = "4" Then Print #dev,whex$;" : V";vx$;" = V";vx$;" + V";vy$ : Return EndIf If act$ = "5" Then Print #dev,whex$;" : V";vx$;" = V";vx$;" - V";vy$ : Return EndIf Print #dev,whex$;" : Unknown code" : Return nine: Rem 9XXX vx$ = Mid$(whex$,2,1) : vy$ = Mid$(whex$,3,1) Print #dev,whex$;" : SKF V";vx$;" <> V";vy$ Return ten: Rem AMMM MMM$ = Right$(whex$,3) Print #dev,whex$;" : I = $";MMM$ Return eleven: Rem BMMM MMM$ = Right$(whex$,3) Print #dev,whex$;" : GOTO $";MMM$;" + V0" Return twelve: Rem CXXX vx$ = Mid$(whex$,2,1) : kk$ = Right$(whex$,2) Print #dev,whex$;" : V";vx$;" = RND AND $";kk$ Return thirteen: Rem DXYN vx$ = Mid$(whex$,2,1) : vy$ = Mid$(whex$,3,1) : n$ = Right$(whex$,1) Print #dev,whex$;" : SHOW ";n$;" @ V";vx$;", V";vy$ Return fourteen: Rem EXXX vx$ = Mid$(whex$,2,1) : ex$=Right$(when$,2) If ex$ <> "9E" And ex$ <> "A1" Then Print #dev,whex$;" : unknown code" : Return EndIf If ex$ = "9E" Then ne$ = " = " If ex$ = "A1" Then ne$ = " <> " Print #dev,whex$;" : SKF V";vx$;ne$;"KEY" Return fifteen: Rem FXXX act$ = Right$(whex$,2) : vx$ = Mid$(whex$,2,1) If act$ = "00" And vx$ = "0" Then Print #dev,whex$;" : STOP" EndIf If act$ = "07" Then Print #dev,whex$;" : V";vx$;" = TIME" : Return EndIf If act$ = "0A" Then Print #dev,whex$;" : V";vx$;" = KEY" : Return EndIf If act$ = "15" Then Print #dev,whex$;" : TIME = V";vx$ : Return EndIf If act$ = "18" Then Print #dev,whex$;" : TONE = V";vx$ : Return EndIf If act$ = "1E" Then Print #dev,whex$;" : I = I + V";vx$ : Return EndIf If act$ = "29" Then Print #dev,whex$;" : I = DSP, V";vx$ : Return EndIf If act$ = "33" Then Print #dev,whex$;" : MI = DEQ, V";vx$ : Return EndIf If act$ = "55" Then Print #dev,whex$;" : MI = V0:V";vx$ : Return EndIf If act$ = "65" Then Print #dev,whex$;" : V0:V";vx$;" = MI" : Return EndIf Print #dev,whex$;" : Unknown code" : Return End Bob Devries Dalby, QLD, Australia |
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Nick Guru  Joined: 09/06/2011 Location: AustraliaPosts: 512 |
Cool Bob. Next is the Chip 8 interpreter! There goes another day! 
Nick |
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djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
original designer of the DREAM-6800 has a webpage including pdf's of original articles at Dream6800 Page And great program Bob from Dalby (BTW i live a few Kms south at clifton) VK4MU MicroController Units |
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brucepython Regular Member  Joined: 19/06/2011 Location: AustraliaPosts: 64 |
This is like seeing a ghost! I have dozens of DREAM 6800 programs on cassettes, probably mostly turned to rust by now, but even if they were OK getting them into the Mite could be quite a challenge. Come to think of it, most were highly dependent on 6800 code, especially those running on the teleprinter which I no longer have. Oh well, I guess there's always Snake... Bruce |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Hi Bruce, Yes, most of the CHIP-8 programmes which were published in "The Dreamer" had some machine code embedded, and all the great games like SPACE INVADERS and GALACTICA were done in pure 6800 machine code. As far as your tapes go, you may be surprised. However, to read them into Maximite would require that you built the tape input part of the DREAM. Once you have that, it's all software, and reasonably trivial. Just follow the code in Mike Bauer's CHIPOS ROM code. The assembly listing is available on his website: Mike Bauer's DREAM 6800 site Regards, Bob Devries Dalby, QLD, Australia |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Oh, and BTW, I've added the address of each line to the output of the disassembler. I'll post the revision here later. How and where does one upload programmes to this forum? Regards, Bob Devries Dalby, QLD, Australia |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
Hey, Nick, Yeah, I'm thinking on that, and also a CHIP-8 assembler 
Regards, Bob Devries Dalby, QLD, Australia |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
Try the furthermost right toolbar icon. |
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| BobDevries Senior Member Joined: 08/06/2011 Location: AustraliaPosts: 266 |
OK, Here's the amended version with addresses (Line numbers) 2012-04-26_082524_CHIPDISA.zip Regards, Bob Devries Dalby, QLD, Australia |
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| Nick Guru Joined: 09/06/2011 Location: AustraliaPosts: 512 |
I wonder if a CHIP 8 interpreter would not be too large to include into the Maximite. Add a boot menu and choose MMBASIC or Chip8 Interpreter. Super Maximite!! Nick |
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| djuqa Guru Joined: 23/11/2011 Location: AustraliaPosts: 447 |
Especially good idea With a couple extra Commands to set and read pin values , it would be great for small apps, games and utilities. VK4MU MicroController Units |
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