use #ifdef i686 to protect Pentium class processors from hanging

src/arch/i386/lib/i386_subr.c

@@ -32,7 +32,6 @@ void intel_cache_on(unsigned long base, unsigned long totalram)
 
 void intel_interrupts_on()
 {
-
 	/* this is so interrupts work. This is very limited scope -- 
 	 * linux will do better later, we hope ...
 	 */
@@ -66,7 +65,9 @@ void intel_interrupts_on()
 	reg &= 0xfffe00ff;
 	reg |= 0x5400;
 	*regp = reg;
-#else
+#else /* !SMP */
+#ifdef i686
+	/* Only Pentium Pro and later have thos MSR stuff */
 	unsigned long low, high;
 
 	printk(KERN_INFO "Enabling interrupts...");
@@ -74,7 +75,8 @@ void intel_interrupts_on()
 	rdmsr(0x1b, low, high);
 	low &= ~0x800;
 	wrmsr(0x1b, low, high);
-#endif
+#endif /* i686 */
+#endif /* SMP */
 
 	printk(KERN_INFO "done.\n");
 	post_code(0x9b);

src/cpu/p5/cpuid.c

@@ -11,9 +11,11 @@ static char rcsid[] = "$Id$";
 #include <cpu/p6/msr.h>
 #endif
 
-#ifdef i586
+
 int intel_mtrr_check(void)
 {
+#ifdef i686
+	/* Only Pentium Pro and later have MTRR */
 	unsigned long low, high;
 
 	DBG("\nMTRR check\n");
@@ -37,8 +39,10 @@ int intel_mtrr_check(void)
 
 	post_code(0x93);
 	return ((int) low);
+#else /* !i686 */
+	return 0;
+#endif /* i686 */
 }
-#endif
 
 void intel_display_cpuid(void)
 {