🚀 go-pugleaf

Ross Ridge <ross@zooid.guild.org> writes:
>I've always understood that under MS-DOS you can't depend on any
>of the '386 registers being preserved.  Anytime I've seen the 32bit
>registers used (eax, edi, ...) it's always been protected inside
>"sti ... cli" instructions to in case some ISR mucks with them.

dstamp@watserv1.uwaterloo.ca (Dave Stampe-Psy+Eng) writes:
>But those are the top bits of a 32-bit register, not a segment register!
>And the loading with a null segment really cannot be anything but 
>deliberate.  It takes about 15 lines of assembley, and switching in
>and out of protected mode to reload a segment descriptor.  So I doubt
>its accidental.

What difference does it make?  All the registers should be saved,
the top bits and the segment registers, but obviously they're not.
It's the same stupid assumption that no other routine will be using
them so there is no need to preserve them.

							Ross Ridge

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