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Forums > CSDb Entries > Release id #5937 : Megademo 1
2006-06-22 07:34
Graham
Account closed

Registered: Dec 2002
Posts: 990
Release id #5937 : Megademo 1

Another demo which simply doesn't work. I assume that the image is ok but the loader simply fucks up everywhere, does anyone know a setup where it is working on? I tried emulator + all drive settings, C128DCR and C64C + 1541-II.

(Another example of a demo which nobody knows because it works nowhere...)
2006-06-22 08:26
Copyfault

Registered: Dec 2001
Posts: 466
Accidently I checked this demo some days ago... setting was also a C64C + 1541 II. At least the parts on the first side seemed to be ok; after diskswapping the loader gave up... Now if my brain wasn't so lousy, I could tell if it worked allright back in the 90's... but I don't think so!

CF
2006-06-22 08:45
Graham
Account closed

Registered: Dec 2002
Posts: 990
For me it didn't even boot the intro. The loader passes some very complicated routines which reminded me of a copy protection and then simply gave up reading track 17. I suspect that the loader has a hardcoded sector header ID.

BAH! Another coder who shouldn't have started drive coding at all.
2006-06-22 08:55
Copyfault

Registered: Dec 2001
Posts: 466
I'm really not sure if this demo worked back then... I assumed that the second side of my copy is just crap. I got the disk somewhen in the nineties...

Can I be of any help with an image of the 1st side of the copy I have here? Guess not, though...

CF
2006-06-25 09:25
Copyfault

Registered: Dec 2001
Posts: 466
I'm not in drivecoding at all, so I've got to ask: what does "hardcoded sector id" mean? Is it possible to copy it? A usual D64-image does not seem to carry this information...

Checked the demo again: semmingly the 2nd side has exactly the same problem Vice has when booting the demo. Is it necessary to recode the loader (which nobody will do anyway;)) in order to make this demo d64-image-compatible?

At least the makers of this demo gave out a (hidden) warning in the notefile, where they say the loader is made up of different routines, including some from EPYX...


CF
2006-06-25 09:42
A3

Registered: Dec 2005
Posts: 362
Found this demo in 3 different collections all supposedly the 100% version. Non of them are working though in emulation mode. Thinking back, I'm now quite convinced that the demo never worked for me at all even on the c64.
2006-06-25 09:58
tlr

Registered: Sep 2003
Posts: 1703
Quoting copyfault
I'm not in drivecoding at all, so I've got to ask: what does "hardcoded sector id" mean? Is it possible to copy it? A usual D64-image does not seem to carry this information...

Checked the demo again: semmingly the 2nd side has exactly the same problem Vice has when booting the demo. Is it necessary to recode the loader (which nobody will do anyway;)) in order to make this demo d64-image-compatible?


The G64-format can contain this (supported by CCS64 & VICE atleast).
http://www.unusedino.de/ec64/technical/formats/g64.html

BTW, Shouldn't a 1541 emulation of a d64 just set the sector-id to the id present in the BAM?
In that case, I don't see why it should not work unless someone has later changed the BAM id of the disk.
The coder of the demo would be quite naive to assume that you'd use a nibbler to copy his demo. ;)

2006-06-25 14:15
hollowman

Registered: Dec 2001
Posts: 474
The version that I first found on the net back in 97 (or something) never worked, and i've felt ashamed ever since, because i uploaded it to antidote without checking it first.

Some time ago Iopop gave me what i believe is a fully working version, which I've uploaded to csdb now.
Perhaps Iopop can tell about all the hassle it was to get a working version transferred to pc =)
2006-06-26 18:22
The Phantom

Registered: Jan 2004
Posts: 360
Hmmm. THe only problems i've had viewing this demo is the ridiculous loading (like there are 2 load phases between each part).

When the intro "looks" finished, hit yer space bar.
On the next (ahem) part, there were no visuals for me, just music. So I hit space and it loaded the next part.

I'm currently on side 2, looking at some "rescue the fractals" part now.

Am I looking at the working version here?

I'm using Vice 1.19, true drive emulation on and PAL for my video. No cart attached and no other "special" features. Seems to be working fine for me.
2006-06-27 08:43
Graham
Account closed

Registered: Dec 2002
Posts: 990
Quote:
BTW, Shouldn't a 1541 emulation of a d64 just set the sector-id to the id present in the BAM?
In that case, I don't see why it should not work unless someone has later changed the BAM id of the disk.

Well, often a demo has it's directory styled after the demo is finished, that also includes changing the disk header + ID. Also, some cartridges have a hardcoded sector header ID in their fast-format routines and don't care for the ID in the directory.

Quote:
The coder of the demo would be quite naive to assume that you'd use a nibbler to copy his demo. ;)

Many loaders have such a hardcoded ID, but in many cases it's enough to assume sector header ID = disk ID. An example is "Follow the Sign 3" by Byterapers.
2006-06-27 10:08
Graham
Account closed

Registered: Dec 2002
Posts: 990
Oh and concerning the sector header ID problem: What do you guys think about a small extension to the D64 format? Adding 2 bytes to a D64 would allow it to have all possible D64 incarnations with or without sector header ID information and still have a 100% detection what kind of D64 it actually is.
2006-06-27 18:30
tlr

Registered: Sep 2003
Posts: 1703
@Graham:
I assume that a disk relying on the disk id being different from the sector id won't survive though many normal/non-nibbler disk copiers on the 64 either. (correct me if I'm wrong here.)

In that case the disk could essentially be considered copy-protected, so it wouldn't be too far fetched to make it a .g64 instead.

How many of these non-intentionally copy-protected releases are there anyway?
2010-11-30 08:29
The Human Code Machine

Registered: Sep 2005
Posts: 109
The loader doesn't do any bad tricks or any other nasty checks, copy protections etc. The loader also doesn't use any hardcoded secotr header ID. It's a simple GI Joe loader improved by MWS/Radwar and myself. The diskside will be checked using a simple file on each side. I think you all got bad transfers of the demo or an unauthorized prerelease. I checked the demo in 1997 on many different setups without any problems!
2010-11-30 09:59
Acidchild

Registered: Jan 2002
Posts: 464
i had problems to transfer this demo back then myself, i think it was a matter of the header and id, which must be the same as on the original disk and wasn't after transfering/copying.
2010-11-30 10:21
chatGPZ

Registered: Dec 2001
Posts: 11100
Quote:
The loader also doesn't use any hardcoded secotr header ID

it definately depends on it, i just tried. take the d64, load it - works. now change the disk id to zeros and try again - doesnt even run the intro anymore.
2010-11-30 11:34
The Human Code Machine

Registered: Sep 2005
Posts: 109
I must be either blind or I'm doing something wrong. Attached the loader source used in the demo. The Searchfilename subroutine could be the problem, but I can't find anything unusual there.

	PROCESSOR 6502

	ORG $9000

;ZEROPAGE ADRESSEN

VARBASE	EQU $E0
ENDFLAG	EQU VARBASE+$0
ZP2	EQU VARBASE+$1
ZP3	EQU VARBASE+$2
ZP4	EQU VARBASE+$3
ZP5	EQU VARBASE+$4
ZP6	EQU VARBASE+$5
ZP7	EQU VARBASE+$6
ZP8	EQU VARBASE+$7
ZP9	EQU VARBASE+$8
ZPA	EQU VARBASE+$9
ZPB	EQU VARBASE+$A
BYTE	EQU VARBASE+$B

;-------------------------------------
;MEMORYS
STARTUP	EQU $0002

;-------------------------------------
;EQUS

;--------------------------------------

;ZEROPAGE FUER SENDCODE
FLOPPYBAL1	EQU $FC
FLOPPYBAH1	EQU $FD
FLOPPYBAL2	EQU $FE
FLOPPYBAH2	EQU $FF

;--------------------------------------
;FLOPPY EQUS

COMMAND	EQU $04
TRACK	EQU $0E
SECTOR	EQU $0F

;--------------------------------------
;NORMALE EQUS

CODE	EQU $AA

DESTINATION	EQU $130

;--------------------------------------
START	SUBROUTINE
	SEI
	CLD
	LDX #$FF
	TXS
	LDA #$37
	STA $01
	INX
	STX $D011
	STX $D418
	STX $D020
	STX $D021
	STX $D015
	STX $D030

	LDY #$1F
.A	LDA $FD30,Y
	STA $0314,Y
	DEY
	BPL .A

	LDA #$7E
	STA $0314

	JSR SEND
	SEI
	LDX #$2F
	TXS

	LDA #$35
	STA $01

	LDA #$97
	STA $DD00

	LDX #$00
.1	LDA DATA1,X
	STA DESTINATION,X
	LDA DATA1+$100,X
	STA DESTINATION+$100,X
	LDA DATA1+$200,X
	STA DESTINATION+$200,X
	INX
	BNE .1

	LDA #$00
	LDX #"S"
	LDY #"0"
	JSR FLOAD
	JMP STARTUP

;------------------------------------------------------------------------------
SEND	SUBROUTINE
	LDA #<FLOPPYCODE
	STA FLOPPYBAL1
	LDA #>FLOPPYCODE
	STA FLOPPYBAH1

	LDA #<FLOPPYSTART
	STA FLOPPYBAL2
	LDA #>FLOPPYSTART
	STA FLOPPYBAH2

.NEXT	JSR INITSEND

	LDA #"M"
	JSR $FFA8
	LDA #"-"
	JSR $FFA8
	LDA #"W"
	JSR $FFA8

	LDA FLOPPYBAL2
	JSR $FFA8
	LDA FLOPPYBAH2
	JSR $FFA8
	LDA #$20
	JSR $FFA8

	LDX #$00
	LDY #$00

.NEXTBYTE	LDA (FLOPPYBAL1),Y
	JSR $FFA8
	INC FLOPPYBAL1
	BNE .OVER1
	INC FLOPPYBAH1

.OVER1	INX
	CPX #$20
	BNE .NEXTBYTE

	JSR $FFAE

	LDA FLOPPYBAL2
	CLC
	ADC #$20
	STA FLOPPYBAL2

	LDA FLOPPYBAH2
	ADC #$00
	STA FLOPPYBAH2
	CMP #$07
	BNE .NEXT

STARTCODE	SUBROUTINE
	JSR INITSEND

	LDX #$00
.1	LDA .TEXT1,X
	JSR $FFA8
	INX
	CPX #$05
	BNE .1

.EXIT	JSR $FFAE

	LDA #$C7
	STA $DD00

	LDY #$00
.2	DEX
	BNE .2
	DEY
	BNE .2
	RTS

INITSEND	LDA #$08
	JSR $FFB1
	LDA #$6F
	JMP $FF93

.TEXT1	DC.B "M-E",#<FLOPPYSTART,#>FLOPPYSTART

DATA1

	RORG DESTINATION

;------------------------------------------------------------------------------
;------------------------------------------------------------------------------
;1 BUCHSTABE NAME =XREG
;1 BUCHSTABE NAME =YREG

;AKKU
;0= LOAD NORMAL
;1= LOAD DECRUNCH


FLOAD	SUBROUTINE
	PHA
	TYA
	PHA

	LDA $DD00
	AND #$0F
	STA ADD001+1
	EOR #$10
	STA SEND2BIT+1
	EOR #$30
	STA ADD003+1
	EOR #$B0
	STA GET+1
	EOR #$50
	STA FIVE+1
	STA ADD006+1

ADD003	LDA #$27
	STA $DD00
	JSR SYNCRO

	TXA
	JSR SENDBYTE2
	PLA
	JSR SENDBYTE2

LOADFLAG	JSR SYNCRO
	PLA
	BNE DECRUNCHALOAD

;----------------------------
NORMAL	SUBROUTINE
	JSR GETBYTE2
	STA WRITE+1
	JSR WAIT12
	JSR GETBYTE2
	STA WRITE+2
	JSR WAIT12

	LDX #$00

.NEXTBYTE	JSR LOADBYTE
	BCS ENDLOAD

	DEC $01
WRITE	STA $FFFF,X
	INC $01

	INX
	BNE .NEXTBYTE
	INC WRITE+2
	BNE .NEXTBYTE

LOADBYTE	SUBROUTINE
	JSR GETBYTE2
	CMP #CODE
	BEQ .CHANGE
	CLC
ENDLOAD	RTS

.CHANGE	JSR GETBYTE2
	CMP #$00
	BEQ .SETCODE
	CMP #$80
	BEQ .LOADEND
	JSR SYNCRO
	JMP LOADBYTE

.SETCODE	LDA #CODE
	CLC
	RTS

.LOADEND	INC ENDFLAG
	SEC
	RTS

;--------------------------------------
DECRUNCHALOAD	SUBROUTINE
	LDA #$00
	STA ENDFLAG

CTRLGET	LDX #$04	;5 CONTROLBYTES LESEN
CTRL1	JSR LOADBYTE
	STA ZP7,X
	DEX
	BPL CTRL1

	LDY ENDFLAG
	BNE ENDLOAD

	DEC $01
	JSR DECRUNCH
	INC $01
	BNE CTRLGET
; PACKER
; SINGLES
DECRUNCH	TYA
	STY ZP2
	STY ZP4
SINGL1	JSR DECOD1
	ROL
	BNE SINGL2
	BCC SEQUE1
SINGL2	ROL ZP4
	JSR DECOD1
	BCS SINGL1
	STA ZP3
	JSR SUBS1
; SEQUENCE LAENGE
SEQUE1	TYA
	STY ZP5
	STY ZP6
SEQUE2	JSR DECOD1
	ROL
	BEQ SEQUE4
	BMI SEQUE3
	JSR DECOD1
	BCS SEQUE2
SEQUE3	INC ZP2
SEQUE4	ADC #$02
	STA ZP3
	AND #$FC
	BEQ GOON
	INC ZP2
GOON	LDX #$03
;PARA-NR.
PARA1	JSR DECOD1
	ROL ZP2
	DEX
	BNE PARA1
;PARA-GET
PARA2	LDX ZP2
	LDA PACKDAT,X
	TAX
	BEQ PARA4
PARA3	JSR DECOD1
	ROL ZP5
	ROL ZP6
	DEX
	BNE PARA3
PARA4	LDA ZP2
	AND #$07
	BEQ PARA6
	INC ZP5
	BNE PARA5
	INC ZP6

PARA5	DEC ZP2
	BPL PARA2
PARA6	LDA ZP8
	ADC ZP5
	STA ZP5
	LDA ZP9
	ADC ZP6
	STA ZP6

	LDA ZP5
	BNE PARA7
	DEC ZP6
PARA7	DEC ZP5

	INC ZP2
	JSR SUBS2
	BEQ DECRUNCH

DECOD1	ASL ZP7
	BNE DECOD4
	CPY ZPA
	BNE DECOD2
	CPY ZPB
	BNE DECOD3
	PLA
	PLA
	RTS

DECOD3	DEC ZPB
DECOD2	DEC ZPA
	PHA
	INC $01
	JSR LOADBYTE
	DEC $01
	LDY #$00
	SEC
	ROL
	STA ZP7
	PLA
DECOD4	RTS

SUBS1	LDA ZPA
	SEC
	SBC ZP3
	STA ZP5
	STA ZPA
	LDA ZPB
	SBC #$00
	STA ZP6
	SBC ZP4
	STA ZPB
SUBS2	LDY ZP3
	BEQ SUBS5
	LDA ZP8
	SEC
	SBC ZP3
	STA ZP8
	BCS SUBS4
SUBS3	DEC ZP9

SUBS4	LDX ZP2
	BEQ LOOP2

LOOP1	LDA (ZP5),Y
	DEY
	STA (ZP8),Y
	BNE LOOP1
	BEQ SUBS5

LOOP2	STY .YVAL+1
	INC $01
	JSR LOADBYTE
	DEC $01
.YVAL	LDY #$00
	DEY
	STA (ZP8),Y
	BNE LOOP2

SUBS5	CPY ZP4
	BEQ SUBS6
	DEC ZP6
	DEC ZP4
	BPL SUBS3
SUBS6	RTS

;--------------------------------------
GETBYTE2	SUBROUTINE
GET	LDY #$00
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	NOP
FIVE	LDY #$00
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY GET+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY FIVE+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY GET+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY FIVE+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY GET+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	NOP
	LDY FIVE+1
	LDA $DD00
	STY $DD00
	ASL
	ROR BYTE
	LDA BYTE
	RTS

SENDBYTE2	SUBROUTINE
	STA BYTE
	LDY #$04

SEND2BIT	LDA #$17
	LSR BYTE
	BCC .1
	ORA #$20
.1	STA $DD00
	NOP
	NOP
	NOP
	NOP
ADD001	LDA #$07
	LSR BYTE
	BCC .2
	ORA #$20
.2	STA $DD00
	DEY
	BNE SEND2BIT
	RTS

SYNCRO	SUBROUTINE
	LDY #$06
.1	DEY
	BNE .1
.2	LDA $DD00
	AND #$40
	BEQ .2
ADD006	LDA #$00
	STA $DD00
	LDY #$05
.3	DEY
	BNE .3
WAIT12	RTS

PACKDAT	DC.B $03,$01,$01,$01,$01,$00,$01,$01
	DC.B $04,$01,$01,$01,$01,$01,$02,$02
	DC.B $04,$01,$01,$01,$01,$02,$02,$02

	REND

;------------------------------------------------------------------------------
;------------------------------------------------------------------------------
FLOPPYCODE

	RORG $0500

FLOPPYSTART	SUBROUTINE
	SEI
	CLD
	LDY #$08
.4	LDA #$10
	STA $1800
.1	DEX
	BNE .1
	LDA #$00
	STA $1800
.2	DEX
	BNE .2
	DEY
	BNE .4
.3	LDA $1800
	AND #$05
	BNE .3
	LDA $1800
	AND #$05
	BNE .3

START2	SUBROUTINE
	LDA #$08
	STA $1800
	LDA $1C00	;LED AUS
	AND #$F7
	STA $1C00
	LDA #$36
	STA $1C07
	CLI

	LDA #$01
.1	BIT $1800
	BEQ .1

	SEI
	LDA #$00
	STA $1800

	JSR GETBYTE	;NAME 1
	STA NAME1+1
	JSR GETBYTE	;NAME 2 
	STA NAME2+1

	LDA #$08
	STA $1800

	LDA $1C00	;LED AN
	ORA #$08
	STA $1C00

SEARCHFILENAME	SUBROUTINE
	CLI
	JSR $D042	;BAM LADEN UND DISK F▄R DISK-WECHSEL
	SEI

	LDY #$01

.NEXTSECTOR	LDX #$12
	STX TRACK
	STY SECTOR

	JSR LOADSECTOR

	LDY #$00
.NEXT	LDA $0702,Y
	AND #$83
	CMP #$82
	BNE .NEXTFILE
	LDA $0705,Y
NAME1	CMP #$00
	BNE .NEXTFILE
	LDA $0706,Y
NAME2	CMP #$00
	BEQ .FILEFOUND

.NEXTFILE	TYA
	CLC
	ADC #$20
	TAY
	BNE .NEXT

	LDY $0701
	BPL .NEXTSECTOR

.FILEFOUND	LDA $0703,Y
	STA TRACK
	LDA $0704,Y
	STA SECTOR

LOADFILE	SUBROUTINE
	JSR LOADSECTOR

	LDA #$00
	STA $1800

	LDA $0700
	BNE .FULLSECTOR

	LDY $0701
	INY
	STY .1+1

	LDY #$02

.2	LDX $0700,Y
	JSR SBYTE
	INY
.1	CPY #$00
	BNE .2

EXITOR	LDX #CODE
	JSR SENDBYTE
	LDX #$80
	JSR SENDBYTE
	JMP START2

.FULLSECTOR	LDY #$02

.3	LDX $0700,Y
	JSR SBYTE
	INY
	BNE .3

	LDA $0700
	STA TRACK
	LDA $0701
	STA SECTOR

	LDX #CODE
	JSR SENDBYTE
	LDX #$7F
	JSR SENDBYTE

;	LDA $1C00
;	EOR #$08
;	STA $1C00

	LDA #$08
	STA $1800
	BNE LOADFILE

LOADSECTOR	SUBROUTINE
	LDX #$06
	CLI

.NEXTTRY	LDA #$80
	STA COMMAND
	
.1	LDA COMMAND
	BMI .1
	CMP #$01
	BEQ .NOERROR
	DEX
	BNE .NEXTTRY

	LDA #$C0
	STA COMMAND
.2	LDA COMMAND
	BMI .2
	JMP LOADSECTOR

.NOERROR	SEI
;	LDA $1C00
;	EOR #$08
;	STA $1C00
	RTS

SBYTE	SUBROUTINE
	CPX #CODE
	BNE SENDBYTE

	JSR SENDBYTE
	LDX #$00
	
SENDBYTE	SUBROUTINE
	STX $14
	LDA #$04
	LSR $14
	LDX #$02
	BCC .1
	LDX #$00
.1	BIT $1800
	BNE .1
	STX $1800
	LSR $14
	LDX #$02
	BCC .2
	LDX #$00
.2	BIT $1800
	BEQ .2
	STX $1800
	LSR $14
	LDX #$02
	BCC .3
	LDX #$00
.3	BIT $1800
	BNE .3
	STX $1800
	LSR $14
	LDX #$02
	BCC .4
	LDX #$00
.4	BIT $1800
	BEQ .4
	STX $1800
	LSR $14
	LDX #$02
	BCC .5
	LDX #$00
.5	BIT $1800
	BNE .5
	STX $1800
	LSR $14
	LDX #$02
	BCC .6
	LDX #$00
.6	BIT $1800
	BEQ .6
	STX $1800
	LSR $14
	LDX #$02
	BCC .7
	LDX #$00
.7	BIT $1800
	BNE .7
	STX $1800
	LSR $14
	LDX #$02
	BCC .8
	LDX #$00
.8	BIT $1800
	BEQ .8
	STX $1800
	RTS

GETBYTE	SUBROUTINE
	LDY #$04
.1	LDA #$04
.2	BIT $1800
	BEQ .2
	LDA $1800
	LSR
	ROR $14
	LDA #$04
.3	BIT $1800
	BNE .3
	LDA $1800
	LSR
	ROR $14
	DEY
	BNE .1
	LDA $14
	RTS

	REND 
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