Re: Is it possible to address more than 1MB in real-mode

Am Sun, 23 Mar 2008 12:37:06 -0700 schrieb H. Peter Anvin:

Dirk Wolfgang Glomp wrote:

The problem is that if any interrupt handler ever goes in the PM, it
will destroy unreal mode on return (there is, unfortunately, no sane way
to read out the segment limits so they can be restored.) So you're
playing a gamble with the underlying platform.

I didn´t know any normal DOS-IRQ that goes to PM, so only memmorymanager do
that?


You don't know what the BIOS does behind the back of either DOS or
anything else. In particular, if the hardware requires access to high
memory (as some disk and network controllers do these days), you have to
go to PM.

For those controllers, i have to go to PM, or the driver is a PM-driver for
the RM, or the BIOS goes to PM and back before DOS is booting?

Dirk

.

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