[comp.binaries.ibm.pc] v01i047: memlist, a second look

cgs@umd5.umd.edu (Chris Sylvain) (12/13/88)

Posting-number: Volume 01 Issue 047
Originally-from: PCResource magazine, November 1988 <no email address>
Submitted-by: cgs@umd5.umd.edu (Chris Sylvain)
Archive-name: memlist/memlist.msg

[ This is an addendum to the posting Message-ID=<4030@bsu-cs.UUCP>,
date=20 Sep 88 23:00:17 GMT, in this newsgroup, which contained the
Memlist program.  The article had a subject heading of:  "memlist, show
MS-DOS memory allocation information".  It is posted here at Chris
Sylvain's request so that it may get archived along with the original
program.  -- R.D. ]

In the November issue of PCResource (that's exactly how it's spelled),
in the PC Techniques article by Hardin Brothers (the original author of
the MEMLIST program posted here) is a box entitled "Second Looks".

Hardin Brothers responds to a number of PCResource readers who
suggested yet another method of finding the head of the MSDOS memory
control block (MCB) chain. The alternate technique uses an UNDOCUMENTED
MSDOS FUNCTION.  The method appears to Hardin Brothers to be
"foolproof" under DOS Versions 2.x and 3.x

Use the following code in the appropriate place MEMLIST:

	mov	AH, 52h
	int	21h		; INT 21h service 52h: undocumented function
				;  returns pointer to head of MCB chain

	mov	AX, Word Ptr ES:[BX-2]	; get segment of MCB head in AX
	mov	ES, AX
	sub	BX, BX		; ES:BX now points to MCB head

-- 
cgs@umd5.umd.edu (Chris Sylvain)
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