Path: utzoo!attcan!uunet!cbmvax!carolyn From: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS) Newsgroups: comp.sys.amiga.tech Subject: Re: Chip RAM Message-ID: <4270@cbmvax.UUCP> Date: 15 Jul 88 22:25:49 GMT References: <3150@polya.Stanford.EDU> <6428@well.UUCP> <2242@sugar.UUCP> <735@applix.UUCP> <11717@agate.BERKELEY.EDU> <2327@antique.UUCP> <737@applix.UUCP> <2333@antique.UUCP> <4790@killer.UUCP> <4266@cbmvax.UUCP> Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS) Organization: Commodore Technology, West Chester, PA Lines: 49 In article <4266@cbmvax.UUCP> carolyn@cbmvax.UUCP (Carolyn Scheppner CATS) writes: >In article <4790@killer.UUCP> ltf@killer.UUCP (Lance Franklin) writes: >[] >>Oh, another thought...with the possibility, in the future, of machines with >>1 meg of CHIP ram, where do I go to find out the actual end of CHIP ram on >>any given machine. > >[I described scanning Exec mem list] Dale points out that it's not a really great idea to depend on the current format of the Exec memlists which should only be dealt with via the provided system functions, since their exact format could change in the future. So one other option would be to make some educated guesses about where some chip mem should be and use the TypeOfMem() function to check those addresses to see of they are CHIP ram. Don't try to check the very top - if Exec puts its stack there, it removes that memory from the memlist so that would probably be NO memory, not CHIP memory. In addition, I believe there may be some 3rd-party ramdisks, etc, that actually grab high memory and remove the memory from the Memlists (not a good idea for future compatibility). Currently, since all CHIP mem is mapped in 1st meg of address space, ignoring the pieces Exec removes from the memlists at the start and end for its own devious purposes, the first 1/2 meg of CHIP is from $0 to $7FFFF, and the second 1/2 meg is from $80000 to $FFFFF. You'l have to pick some addresses within the second 1/2 meg range to try TypeOfMem() on, low enough to avoid system stack and possible 3rd party high-chip memlist removals. You could just check $80000, but remember that this will not tell you if this RAM is free. Just that it exists. Why do you need to know the highest CHIP address they have ???? Wouldn't it be better to know how much CHIP ram they have FREE ?????? That's easy - AvailMem(MEMF_CHIP) -- ========================================================================== Carolyn Scheppner -- CATS Commodore Amiga Technical Support PHONE 215-431-9180 UUCP ...{uunet,allegra,rutgers}!cbmvax!carolyn Oh I'm a numberjack and I'm OK, I code all night and I work all day... ==========================================================================