From mboxrd@z Thu Jan  1 00:00:00 1970
From: James Courtier-Dutton <James@superbug.co.uk>
Subject: [Patch]  Fix DOS get time function.
Date: Fri, 16 Nov 2007 02:56:32 +0000
Message-ID: <473D06E0.1030507@superbug.co.uk>
Mime-Version: 1.0
Content-Type: multipart/mixed;
 boundary="------------020904070103040101090507"
Return-path: <linux-msdos-owner@vger.kernel.org>
Sender: linux-msdos-owner@vger.kernel.org
List-Id: <linux-msdos.vger.kernel.org>
To: linux-msdos@vger.kernel.org

This is a multi-part message in MIME format.
--------------020904070103040101090507
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Hi,

The current DOS INT 21 AH=2C  get time function returns incorrect 
results, and is sometimes hours off.
The attached patch fixes the problem.
It should patch against DOSBOX 0.72
the (X * 500 / 91)  is the same as  X * 100 / 18.2


Signed-off-by:  James@superbug.co.uk

James


--------------020904070103040101090507
Content-Type: text/x-patch;
 name="time-fix.diff"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
 filename="time-fix.diff"

--- src/dos/dos.cpp.org	2007-11-16 02:46:35.000000000 +0000
+++ src/dos/dos.cpp	2007-11-16 02:54:50.000000000 +0000
@@ -348,8 +348,9 @@
 //TODO Get time through bios calls date is fixed
 		{
 /*	Calculate how many miliseconds have passed */
-			Bitu ticks=5*mem_readd(BIOS_TIMER);
-			ticks = ((ticks / 59659u) << 16) + ((ticks % 59659u) << 16) / 59659u;
+			/* seconds = ticks / 18.2 */
+			Bitu ticks=500 * mem_readd(BIOS_TIMER);
+			ticks = ticks / 91;
 			Bitu seconds=(ticks/100);
 			reg_ch=(Bit8u)(seconds/3600);
 			reg_cl=(Bit8u)((seconds % 3600)/60);

--------------020904070103040101090507--