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Text File | 1994-08-12 | 10.6 KB | 362 lines

************************************************************** ****** HOW TO CONVERT C64 TUNES TO AMIGA PLAYSID FORMAT ****** ************************************************************** Requirements: * You have to know 6502 machinecode quite well. * You have access to a C64 or a good Emulator * You have an good machine code monitor to your C64 or Emulator and it will be easier if... * You have a 1541 diskdrive * You have a transfer cable C64-Amiga * You have already ripped tunes * You know a lot about SID Ripping: This is often a hard thing to do. You should locate where in memory that the musicplayer and data is. If it is spread into several parts, then you have to write memory transfer routines. You should find where to call to init and start the different tunes. You then save the music in one (this is very important) file. You should always try to locate as many tunes or sounds as possible, so that nothing is forgotten. Otherwise your job maybe will be re-done by another guy who has found more tunes. Converting: This is easier. If you have already ripped tunes that consists of more than one file, see instructions on ripping. Now you should rewrite the music player so that it can be thought of as two major subroutines (sometimes this is already the case, like Maniacs of Noise). The first subroutine will be called by PlaySID with the accumulator set to the tunenumber (hex $00-$FF). This should initalize all things like volume etc. The second subroutine is the real music playing part. This will be called by PlaySID each 1/50 or 1/60 second (set by parameters in .info). Note that this routine routine should be ended by either RTI, RTS or a jump to address $Exxx (this because the non-used bytes at $E000-FFFF is filled with $40=RTI). If you use RTS you must then also check that the stackpointer is ok (the same as when called from PlaySID). Note that the memory transfer routines should be in the first subroutine. Note also that PlaySID initializes all 64k of memory and reloads the musicplayer each time you press play. Note also that the memory control register ($01) is of nearly no use under PlaySID. It sees all memory as ram (even $D000-$DFFF!). Sometimes the music uses the fourth channel, like sample channel. This is done by changing the volume ($D418) very often. Usually this is programmed using the NMI ($0318 or $FFFA). PlaySID uses another metod. The SID registers are enhanced with several new registers, see below. You have to write a routine that is a part of the second subroutine. This routine replaces the NMI routine, and with that follows that the NMI routine are not used anymore. For some examples look below (although they're not NMI's but they'll explain the way to convert). Please always write to the START reg ($D41D) after you have set the other regs, for future revisions of PlaySID. Transfering: When you transfer the files, you don't have to remove the 2 bytes in the beginning of the file (if you let them be, you could also use the files in some C64emulator that maybe will be released). If you haven't got the opportunity to transfer by yourself, you could send the files to us (the authors of PlaySID) on a 5 1/4 disk or even cassette. If you do, the you must include the information about the .info parameters. Making the Icon: Just copy an icon from an existing PlaySID file. For example copy arkanoid.info to <filename>.info. Then select the icon in workbench and select Information in the workbench menu. Now you change the parameters to that of your file. Look at PlaySID.doc for a complete description of the parameters. It is very much appreciated that you also include information about author and copyright. You could even include lines like RIPPER="xxxx" or VERSION="xxxxx", because these lines are not seen by PLAYSID. New Icon Tooltype Features (V2.2): If 0 is specified as loadaddress, the first two bytes of the file will instead be used as loadaddress. If 0 is specified as initaddress, then the initaddress will be the first C64 address loaded. If 0 is specified as playaddress, then the playaddress will be the address of the interrupt initialized by the subroutine at the initaddress. This address will be the contents of $0314/0315 or $FFFE/FFFF depending on what value $0001 contains. SPEED = <speeddata> ;in hex speeddata contains info about playspeed. For each tune a bit is reserved, bit 0 for tune nr 1 and so on. A 0 bit means vertical sync (50Hz PAL or 60Hz NTSC) and a 1 bit means 60 Hz or the time set in $DC04/05. Default value is 0 for all bits. Appendix: ********************* * NEW SID REGISTERS * ********************* ADDRESS VALUE FUNCTION USAGE D41D 00-FC Nr of tones-1 Galway-Noise (START) FD Stop Sampling Sample (STOP) FC Start Sampling with 1/4 Sample (START) volume FE Start Sampling with 1/2 Sample (START) volume FF Start Sampling Sample (START) ex. 4-bit sample -> FF 3-bit sample (one extra LSR) -> FE etc. note. only write to this reg after setting the other regs to proper values. D41E 00-FF ToneData address lowbyte Galway-Noise D41F 00-FF ToneData address highbyte Galway-Noise D41E 00-FF SampleData address low Sample D41F 00-FF SampleData address high Sample D43D 00-FF Tonelength (in samples) Galway-Noise D43E 00-0F Volume of Noise Galway-Noise D43D 00-FF SampleData end addr. low Sample D43E 00-FF SampleData end addr. high Sample D43F 00-FF Period for each value of Galway-Noise ToneData (in C64-cycles) 00-FE Nr times of Repeat Sample FF Continious sample Sample D45D 00-FF Period for value 0 of Galway-Noise ToneData (in C64-cycles) 00-FF Period for samples lowbyte Sample D45E 00-FF Period for samples highbyte Sample (in C64-cycles) ex. the period is usually the value of the timer on 6526 ($DD04,05 etc.) which handles the NMI-irq used D45F 00,01 Nr of bytes to add after Sample 02,04 Reading one nibble (4 bits) 08... (i.e. Octave) ,usually 00 ex. xx xx xx xx ... -> 00 x_ x_ x_ x_ ... -> 01 x_ __ x_ __ ... -> 02 etc. D47D 00 Sampleorder: Lownibble Sample ,Highnibble (the most used) 01 Sampleorder: Highnibble Sample ,Lownibble ex. (12 34 -> 1 2 3 4) -> 01 (12 34 -> 2 1 4 3) -> 00 D47E 00-FF SampleData repeataddress low Sample D47F 00-FF SampleData repeataddress high Sample * EXAMPLES * ; *** MARTIN GALWAY *** *** NOISE *** ; 6502 Routine: ; Loop of Y=5 to 0 step -1 ; Loop of X=19 to 0 step -1 ; Read $B64E,Y in A ; Wait A*73 cycles ; Wait 22 cycles ; Add 7 to volume ; End Loop X ; End Loop Y ; END ; ; Replacement with: ; D43D=$19 ; D41E=$4E, D41F=$B6 ; D43F=$73 ; D45D=$22 ; D43E=$07 ; D41D=$05 ; ; *** MARTIN GALWAY *** *** SAMPLE *** ; 6502 Routine: ; Loop of Y=0 to 100 step 1 ; Read $B64E,Y in A ; Write Lownibble of A in Volumereg ; Wait 74 cycles ; Write Highnibble of A in Volumereg ; Wait 74 cycles ; End Loop Y ; Do it one more time ; END ; ; Replacement with: ; D41E=$4E, D41F=$B6 ; D43D=$4E, D43E=$B7 ; D45D=$74, D45E=$00 ; D45F=$00 ; D47D=$00 ; D43F=$01 ; D47E=$4E, D47F=$B6 ; D41D=$FF ; ; ; *** ORDINARY SAMPLE *** ; 6502 NMI-irq Routine: ; Checks if all is played ($FC,$FD = $FE,$FF ?) ; Loads next byte with LDA ($FC),Y (Y = 0) ,if so required ; Shift outs the highnibble , if so required ; Stores this value in $D418 ; Exits (RTI) ; ; Replacement with: ; Locate the routine which initalizes the values $FC-$FF and which starts ; the NMI-irq (Probably with LDA #$81,STA $DD0D ,LDA #$xx,STA $DD04 ; LDA #$yy,STA DD05 etc.) ; Do instead this, ; D41E,1F = value of adress $FC,FD ; D43D,3E = value of adress $FE,FF ; D43F = 00 , D45F = 00 ; D47D = 00 or 01 ; D45D,5E = value of address $DD04,05 ; D41D = FF ; *********************************** * UNIMPLEMENTED 6502 INSTRUCTIONS * *********************************** Complete list of the unimplemented instructions for the 6510 microprocessor. (C) 1984,1992 Håkan Sundell Notes: In the listing belove there are some shortcuts used, A = Accumulator , X = Index register X , Y = Index register Y , SP = Stackpointer , M = byte in Memory , -> = is Stored in. The flag settings are, unless other specified, calculated in the same way as the consisting intructions. Code Adress-mode Description 02 --- Total HALT 03 (Ind,X) ASL,ORA 04 Zeropage NOP 07 Zeropage ASL,ORA 0B Immediate AND #$xx,ASL A with only setting flags 0C Absolute NOP 0F Absolute ASL,ORA 12 --- Total HALT 13 (Ind),Y ASL,ORA 14 Zeropage NOP 17 Zeropage,X ASL,ORA 1A Implied NOP 1B Absolute,Y ASL,ORA 1C Absolute NOP 1F Absolute,X ASL,ORA 22 --- Total HALT 23 (Ind,X) ROL,AND 27 Zeropage ROL,AND 2B Immediate AND #$xx,ROL A with only setting flags 2F Absolute ROL,AND 32 --- Total HALT 33 (Ind),Y ROL,AND 34 Zeropage NOP 37 Zeropage,X ROL,AND 3A Implied NOP 3B Absolute,Y ROL,AND 3C Absolute NOP 3F Absolute,X ROL,AND 42 --- Total HALT 43 (Ind,X) LSR,EOR 44 Zeropage NOP 47 Zeropage LSR,EOR 4B Immediate AND #$xx,LSR A 4F Absolute LSR,EOR 52 --- Total HALT 53 (Ind,Y) LSR,EOR 54 Zeropage NOP 57 Zeropage,X LSR,EOR 5A Implied NOP 5B Absolute,Y LSR,EOR 5C Absolute NOP 5F Absoulte,X LSR,EOR 62 --- Total HALT 63 (Ind,X) ROR,ADC 64 Zeropage NOP 67 Zeropage ROR,ADC 6B Immediate AND #$xx,ROR A 6F Absoulte ROR,ADC 72 --- Total HALT 73 (Ind),Y ROR,ADC 74 Zeropage NOP 77 Zeropage,X ROR,ADC 7A Implied NOP 7B Absolute,Y ROR,ADC 7C Absolute NOP 7F Absolute,X ROR,ADC 80 Zeropage NOP 82 Zeropage NOP 83 (Ind,X) 0->M if X=0 , No flags set 87 Zeropage A and X -> M , No flags set 8B Immediate M and X -> A (bits 7-1) , M0 and X0 and A0 -> A0 , No flags set 8F Absolute A and X -> M , No flags set 92 --- Total HALT 93 (Ind),Y A and X and $21 -> M , No flags set 97 Zeropage,Y A and X -> M , No flags set 9B Absolute,Y A and X and $21 -> M , A and X -> SP, No flags set 9C Absolute,X A and Y and $21 -> M , No flags set 9E Absolute,Y A and X and $21 -> M , No flags set 9F Absolute,Y A and X and $21 -> M , No flags set A3 (Ind,X) LDA,LDX A7 Zeropage LDA,LDX AB Immediate LDA,LDX AF Absolute LDA,LDX B2 --- Total HALT B3 (Ind),Y LDA,LDX B7 Zeropage,Y LDA,LDX BB Absolute,Y SP and M -> A,X,SP BF Absolute,Y LDA,LDX C2 Zeropage NOP C3 (Ind,X) DEC,CMP C7 Zeropage DEC,CMP CB Immediate (X and A) - M -> X CF Absolute DEC,CMP D2 --- Total HALT D3 (Ind),Y DEC,CMP D4 Zeropage NOP D7 Zeropage,X DEC,CMP DA Implied NOP DB Absolute,Y DEC,CMP DC Absolute NOP DF Absolute,X DEC,CMP E2 Zeropage NOP E3 (Ind,X) INC,SBC E7 Zeropage INC,SBC EB Immedite SBC #$xx EF Absolute INC,SBC F2 --- Total HALT F3 (Ind),Y INC,SBC F4 Zeropage NOP F7 Zeropage,X INC,SBC FA Implied NOP FB Absolute,Y INC,SBC FC Absolute NOP FF Absolute,X INC,SBC