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Date: | Tue, 2 May 2000 13:34:15 +0300 (IDT) |
From: | Eli Zaretskii <eliz AT is DOT elta DOT co DOT il> |
X-Sender: | eliz AT is |
To: | muller AT cerbere DOT u-strasbg DOT fr |
cc: | djgpp-workers AT delorie DOT com |
Subject: | Re: interrupt 0x75 limitation in Win95 ? |
In-Reply-To: | <3.0.6.32.20000429014940.00aa43e0@ics.u-strasbg.fr> |
Message-ID: | <Pine.SUN.3.91.1000502133356.21668M-100000@is> |
MIME-Version: | 1.0 |
Reply-To: | djgpp-workers AT delorie DOT com |
Errors-To: | nobody AT delorie DOT com |
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On Sat, 29 Apr 2000 muller AT cerbere DOT u-strasbg DOT fr wrote: > Even a win32 executable raising a FPU exception does > not get it if it is run from a Dos executable > that sets the 0x75 interrupt vector! > The interrupt called is allways that of the first Dos > program loaded in the calling chain. This might or might not be relevant: the FP exception handling in DOS programs is very different (for historical reasons) from the ``normal'' way FP exceptions are raised and processed by Intel CPUs in protected mode. The normal way is to generate exception 0 or 16, not to trigger Int 75h. So it might be that the juggling done by Windows to translate the FP exception to the DOS-style interrupt is somehow involved in this mess, especially when there's a mix of DOS and native Win32 programs. Also note that the Win32 program runs in a different virtual machine, which could further complicate the issue of passing the exception to the correct program.
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