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From:	"Rod Pemberton" <buzzoff AT nonamewhichexists DOT cmm>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Possible issue with CWSDPMI's VCPI check
Date:	Thu, 13 Nov 2014 20:07:03 -0500
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To:	djgpp AT delorie DOT com
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I was working on some assembly code unrelated to DJGPP.
I just noticed that MS-DOS v7.10 (Windows SE) reports
VCPI is installed even when I have both NOVCPI and
NOEMS parameters on my EMM386.EXE line in CONFIG.SYS.
For my assembly code call to Int 67h, AX=DE00h,
MS-DOS v7.10 returns AH=0 (installed) if EMM386.EXE
was loaded, both with and without the NOVCPI NOEMS
parameters.

This means the code below from main1() in CONTROL.C
for CWSDPMI doesn't work as it appears it should work.
DOS does seem to disable VCPI with NOVCPI NOEMS.
DJGPP's GREP against a bunch of files quietly exited
without displaying results which should've been found,
and without CWSDPMI emiting the error message.

   use_xms = xms_installed();

   ems_init();
   if (cpumode()) {		/* We are in V86 mode */
     if (!(vcpi_installed = vcpi_present())) {
       ems_free();
       errmsg("Protected mode not accessible.\n");
       exit(1);
     }
   }


Rod Pemberton

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