Path: utzoo!utgpu!water!watmath!clyde!att!ihnp4!cbmvax!carolyn
From: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Chip RAM
Message-ID: <4266@cbmvax.UUCP>
Date: 15 Jul 88 00:49:57 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>
Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner CATS)
Organization: Commodore Technology, West Chester, PA
Lines: 34

In article <4790@killer.UUCP> ltf@killer.UUCP (Lance Franklin) writes:
>Speaking of Chip RAM...just out of curiosity, does LoadSeg ever span CHIP and 
>FAST ram when loading hunks?  I.E. if I check the starting address of a
>structure to see if it's in CHIP or FAST ram, am I assured that the end of
>that structure will also be in the same ram, assuming it's all in the same
>chunk (a given, I think).

Since CHIP and FAST ram are in separate memlists, you don't have to worry
about any loaded segment spanning CHIP and FAST ram.  And since a
structure must be contiguous memory (else the offsets to its members
would not work), you should never have to worry about a structure being
split between 2 segments or two allocations.

>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.

The Exec MemList (ExecBase->MemList) is an exec List.  It's lh_Head
is the first MemHeader structure (whose ln_Succ is the next, etc).
One of the MemHeaders has the attribute bit for MEMF_CHIP set in its
mh_Attributes.  That's the CHIP memory MemHeader structure.  Its
member mh_Upper is the high address (+1) of the last byte.  Note that
there may actually be a bit more chip ram that this Upper value because
the system stack may be at the top of chip ram.

See the exec/memory.h include file.

-- 
==========================================================================
  Carolyn Scheppner -- CATS  Commodore Amiga Technical Support
  PHONE 215-431-9180   UUCP  ...{uunet,allegra,rutgers}!cbmvax!carolyn 

 "Toto, somehow I don't think we're in Kansas anymore"  -  Dorothy
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