From:	"Chih-Hao Tsai" <hao DOT tsai AT uiuc DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	PCTIMER 1.4
Date:	Sat, 14 Mar 1998 06:24:35 -0600
Organization:	University of Illinois
Lines:	44
Message-ID:	<6edsu4$1a3$1@vixen.cso.uiuc.edu>
NNTP-Posting-Host:	archbald-15.slip.uiuc.edu
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I am about to upload PCTIMER 1.4, the latest version of my millisecond
resolution timing library to SimTel.  (Within a week or so, I
suppose.)

The current version, PCTIMER 1.3 was released more than two years ago.
Over the years it has been reported that this version does not work
very well.  Especially when compiled with DJGPP V2 and executed under
Win95, the timer frequency will be double.  So I read the latest
DJGPP FAQ and found that "hardware interrupts are always passed to
protected mode first, and only if unhandled are they reflected to real
mode".

It appears that there's no need to implement both real and protected
mode handlers.  So I removed the protected mode handler and tested
the program again.  No particular problem observed.  Everything seemed
to be ok.

PCTIMER now also locks data and code for the real mode handler, as
instructed in the FAQ.

Regarding Win95, it is really not a good idea for a program to
touch hardware interrupts.  The Win32 Multimedia Timer API has
the ability to do millisecond resolution timing, but I am not
sure if RSXNT supports winmm.lib.  I also included a document on
using Win32 API to do regular and millisecond timing with Visual
C++ 4.0 on Win95 platform.


Hao
--
;; .signature -- defines a variable containing information about hao
(defvar hao '((name-english "Chih-Hao Tsai") (name-chinese "˝˛§ÓŻE")
(organization "Beckman Institute, UIUC") (email "hao DOT tsai AT uiuc DOT edu")
(homepage "http://casper.beckman.uiuc.edu/~c-tsai4") (icq 5734422)))



--
;; .signature -- defines a variable containing information about hao
(defvar hao '((name-english "Chih-Hao Tsai") (name-chinese "˝˛§ÓŻE")
(organization "Beckman Institute, UIUC") (email "hao DOT tsai AT uiuc DOT edu")
(homepage "http://casper.beckman.uiuc.edu/~c-tsai4") (icq 5734422)))

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