From: tholo <tholo@openbsd.org>
Date: Mon, 6 May 1996 20:29:38 +0000 (+0000)
Subject: Zero the instruction counter on Pentium's after detecting one if we have
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=6e04bc6b518516bfbb9fdcfe4aa19f8deaf3a176;p=openbsd

Zero the instruction counter on Pentium's after detecting one if we have
NTP code compiled in; prevents division errors in microtime()
---

diff --git a/sys/arch/i386/i386/locore.s b/sys/arch/i386/i386/locore.s
index 9d6eb1775d3..bd1ca34badf 100644
--- a/sys/arch/i386/i386/locore.s
+++ b/sys/arch/i386/i386/locore.s
@@ -437,6 +437,13 @@ try586:	/* Use the `cpuid' instruction. */
 	jb	is486			# less than a Pentium
 	movl	$CPU_586,RELOC(_cpu)
 
+#ifdef NTP
+	xorl %eax,%eax
+	xorl %edx,%edx
+	movl $10,%ecx
+	.byte 0xf, 0x30			# wrmsr (or trap on non-pentium :-)
+#endif
+
 2:
 	/*
 	 * Finished with old stack; load new %esp now instead of later so we