Date: Tue, 2 May 2000 13:34:15 +0300 (IDT) From: Eli Zaretskii 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: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: djgpp-workers AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: djgpp-workers AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk 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.