Date: Tue, 16 Mar 1999 21:28:47 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Luoqi Chen <luoqi@watermarkgroup.com> Cc: current@FreeBSD.ORG Subject: Re: VM86 assembly code problem Message-ID: <199903170528.VAA24119@apollo.backplane.com> References: <199903170413.XAA14900@lor.watermarkgroup.com>
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:There're a couple of places in swtch.s where code looks like this,
:
:#ifdef VM86
: btrl %esi, _private_tss
: je 3f
: ...
:3:
:#endif
:
:The conditional jump statement doesn't seem right, according to manual,
:btrl instruction modifies CF flag but not Z, so the jump should be jae/jb
:instead of je/jne. Could anyone confirm this?
:
:-lq
btrl only effects the Carry. The VM86 code looks wrong to me, though
there is an outside chance that it is doing a conditional jump based
on something that occured prior to the btrl.
-Matt
Matthew Dillon
<dillon@backplane.com>
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