On Tue, 10 Aug 2010, Daniel Kahlin wrote: > > On Tue, 10 Aug 2010, Anders Carlsson wrote: > >> Daniel Kahlin wrote: >> >>> Anyway a quick analysis shows that the game loads $027A-$2000. The first >>> chunk at $027A looks like a cassette header indicating a file "FLASH >>> ATTACK" $03FD-$2000 >> >> Bill Degnan wrote: >> >>> Yes. Now try to save this to cassette using the TIM prompt using standard >>> procedure. Something prevents dumping the memory to tape. >> >> While I haven't studied the PET memory map recently, isn't $03FD part of >> the cassette buffer? If so, perhaps the computer rebuilds that part of >> memory when you save in a normal way, and you lose whatever was there. > > From what I can tell it isn't part of the cassette buffer. Judging from the > flash attack file there is space for two cassette buffers. > One from $027A-$0339 and one from $033A to $03F9. > Though, the layout in the flash attack file could be a decoy. > > I'm leaning towards that there might be a different low limit for tape > saving on the PET. IIRC this limit is $0300 on the C64 and VIC20. > > Will check in vice when I get home tonight. Ok. This supposedly works: (on a two tape BASIC 4.0 box) LOAD"FLASH ATTACK",8 SYS1024 S"FLASH ATTACK",02,027A,2000 I can't test because only one tape port is emulated in vice. Note that this is shown in the petfaq section "WHAT ARE THE COMMANDS FOR THE M/L MONITOR?": http://www.zimmers.net/cbmpics/cbm/PETx/petfaq.html It seems the crucial sections are: $03FE=$9D & $03FF=$DA, and that the tape header in buffer 1 is correct but $02AB-$0339 are $00. (the default is $20) :027A 01 FD 03 00 20 46 4C 41 .... FLA :0282 53 48 20 41 54 54 41 43 SH ATTAC :028A 4B 00 00 00 00 00 00 00 K....... :0292 00 00 00 00 00 00 00 00 ........ ... I assume this is checked within the virtual machine to make it a bit more complicated. ;) Btw, there is some residual source code at $0A68-$0B8D... /Daniel Message was sent through the cbm-hackers mailing listReceived on 2010-08-10 20:00:03
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