Playaround Demo

[Omegamatrix]

Here is the checksum from the demo, and the checksum from Bachelor Party side by side. After accounting for the different registers that are used then they are almost exactly the same routine.

 

 

			DEMO					 BACHELOR PARTY

   lda	#$30				  lda	#$30
   sta	romHigh			   sta	romHigh
   lda	#0
   sta	checksumVal								   ; the demo reclears these
   sta	romLow
.loop:					   .loop:
   ldy	#0					ldy	#0
   lda	(romAddress),Y		lda	(romAddress),Y
   clc						  clc
   adc	checksumVal		   adc	checksumVal
   sta	checksumVal		   sta	checksumVal
   inc	romLow				inc	romLow
   bne	.loop				 bne	.loop
   sec						  sec
   lda	#0					lda	#0
   adc	romHigh			   adc	romHigh
   sta	romHigh			   sta	romHigh
   cmp	#$40				  cmp	#$40
   bne	.loop				 bne	.loop
   lda	CHECKSUM_VALUE		lda	CHECKSUM_VALUE
   cmp	checksumVal		   cmp	checksumVal
   bne	.crash				bne	.crash
   rts						  rts

.crash:					  .crash:
   lda	#$F1				  lda	#9			   ; different audio value
   sta	AUDC0				 sta	AUDC0
   sta	AUDF0				 sta	AUDF0
   sta	AUDV0				 sta	AUDV0
   jmp	($3FFE)			   jmp	($3FFE)

 

The difference though is Bachelor Party does use a origin of $3000, and the demo uses $F000. From what I saw this was the only bit of code in the demo that used $3000 as an origin. So it seems it came from Bachelor Party.

 

 

I did a search through all the Mystique/Playaround roms for 60,FE,3F in HOM3, which translates into jmp ($3FFE). Bachelor Party was the only hit. The checksum routine is in both the Mystique and Playaround versions of Bachleor Party, as well as the Demo of course.

[Godzilla]

Wow, thats awesome, thanks for sharing, JG

[Wickeycolumbus]

I thought some of you may be interested in this, here is what the Mystique logo looks like (displayed in the demo):

 

 

The ROM attached has the Mystique logo in place of the 69 position.

Mystique.bin