ftp.delorie.com/archives/browse.cgi | search |
X-Authentication-Warning: | delorie.com: mail set sender to djgpp-bounces using -f |
From: | Jason Mills <jmills AT cs DOT mun DOT ca> |
Newsgroups: | comp.os.msdos.djgpp |
Subject: | Re: Timer inside interrupt handler |
Date: | Sun, 24 Oct 2004 13:05:32 -0230 |
Organization: | Memorial University of Newfoundland |
Lines: | 30 |
Message-ID: | <clgi45$pd8$1@coranto.ucs.mun.ca> |
References: | <clee5f$j5s$1 AT coranto DOT ucs DOT mun DOT ca> <01c4b948$Blat.v2.2.2$f034ea00 AT zahav DOT net DOT il> |
NNTP-Posting-Host: | jmills.ccore.mun.ca |
Mime-Version: | 1.0 |
X-Trace: | coranto.ucs.mun.ca 1098632133 26024 134.153.38.195 (24 Oct 2004 15:35:33 GMT) |
X-Complaints-To: | usenet AT coranto DOT ucs DOT mun DOT ca |
NNTP-Posting-Date: | Sun, 24 Oct 2004 15:35:33 +0000 (UTC) |
User-Agent: | Mozilla Thunderbird 0.7.3 (Windows/20040803) |
X-Accept-Language: | en-us, en |
In-Reply-To: | <01c4b948$Blat.v2.2.2$f034ea00@zahav.net.il> |
To: | djgpp AT delorie DOT com |
DJ-Gateway: | from newsgroup comp.os.msdos.djgpp |
Reply-To: | djgpp AT delorie DOT com |
Errors-To: | nobody AT delorie DOT com |
X-Mailing-List: | djgpp AT delorie DOT com |
X-Unsubscribes-To: | listserv AT delorie DOT com |
Eli Zaretskii wrote: > How about reading the BIOS tick counter? That's a simple memory read > from a fixed address, so it should be safe. The resolution you get is > 54 msec. How exactly? (As you can see I have not had much experience at low level programming). _bios_timeofday() issues an Int (according to the sources). I did come across the following on the newgroup. Does it implement what you suggest? #include <go32.h> include <sys/farptr.h> A variable: long tick; Convert the real mode segment:offset pair to a linear address offset (relative to _dos_ds) like this: 0x40 * 16 + 0x6c = 0x460 Use it in the _farpeekl() function like this: tick = _farpeekl(_dos_ds, 0x460); > OTOH, invoking any library functions that may issue Int 21h or other > real-mode software interrupts is a no-no in an interrupt handler. Thanks.
webmaster | delorie software privacy |
Copyright © 2019 by DJ Delorie | Updated Jul 2019 |