Path: utzoo!mnetor!uunet!husc6!cmcl2!nrl-cmf!ames!oliveb!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Alloc Remember sytems.
Message-ID: <49383@sun.uucp>
Date: 13 Apr 88 17:26:12 GMT
References: <2804@crash.cts.com>
Sender: news@sun.uucp
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Organization: Sun Microsystems, Mountain View
Lines: 34

In article <2804@crash.cts.com> haitex@pnet01.cts.com (Wade Bickel) writes:
>    The puzzle is how to handle the case where CHIP memory is allocated in
>place of FAST memory (ie: No FAST mem. was avail).  This must be fast! 

Well my allocator uses Exec nodes linked together to create 'remember'
list. The following routines are implemented :
	(char *)mmalloc(mptr,size,attributes);
	/* just like alloc remember :-) */
	SHORT mmark(mptr); 
	/* Returns a memory "marker" */
	BOOL mfreemark(mptr,int);
	/* Free's everything past the mark */
	BOOL mfree(mptr,ptr); 
	/* Free memory associated with this pointer */
	BOOL mfreeall(mptr);
	/* Free all memory associated with this pointer */ 

The structure that this maintains looks something like this :
struct mmallocstruct {
	struct Node	mm_Node;	/* Node list (14 bytes)   */
	int		mm_Mark;	/* Memory "marker"   	  */
	int		mm_Size;	/* Memory chunk size 	  */
	int		mm_Pad;		/* force longword alignment */
	long		mm_Data;	/* First longword of data */
	}	
The allocations actually allocate enough memory to store both the memory
node and the data and return a pointer to the data. &(mm.mm_Data)

Now it does "waste" 20 bytes each time you allocate something but it 
is useful.

--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.