Date: Tue, 10 Aug 2004 10:46:50 -0600 From: <soralx@cydem.org> To: freebsd-hackers@freebsd.org Cc: breath@unix.net Subject: Re: Reboots after "OR AL,1 MOV CR0, EAX" on some computers. Message-ID: <200408101046.50543.soralx@cydem.org> In-Reply-To: <opsa64r8l1s5rhgt@smtp.hotpop.com> References: <opsa64r8l1s5rhgt@smtp.hotpop.com>
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> good free environment for initialization and further running. Shortly: ON > SOME COMPUTERS (MAYBE CPUS) I GET REBOOTING JUST ON 'JMP' INSTRUCTION > AFTER PE BIT IS ENABLED. I've got no reboots on all i386, i486, i586 > computers that I tryed to boot from. I have a Pentium III Celeron > (Coppermine) 900MHz - no reboots. Also tested on some Pentium II 400MHz - > no reboots. But on other side Pentium IV (don't remember speed) gave me a > reboot. And other computer I was not able to see processor model (maybe > PentiumIV !?) gave me a reboot too. Using endless loop stop points I > figured out that reboot is before any instruction pointed by 'protected' > label and that reboot happens after setting the PE bit. I've tested the code on a Dual-CPU P-166 - the system always goes into cold reboot. I first thought that SMP systems need some special procedure to switch to protected mode (the fact that all Pentium IV CPUs have second logical processor helps the idea), but then I tested it on Athlon XP system - reboots also. I'll play with it later. Maybe somebody at freebsd-hackers know the answer? Timestamp: 0x4118F317 [SorAlx] http://cydem.org.ua/ ridin' VN1500-B2
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