diff -Bru 2.4-acpi/include/asm-i386/smpboot.h patched/include/asm-i386/smpboot.h
--- 2.4-acpi/include/asm-i386/smpboot.h	2004-01-08 17:10:21.000000000 +0800
+++ patched/include/asm-i386/smpboot.h	2004-01-08 17:09:41.000000000 +0800
@@ -82,9 +82,13 @@
 
 static inline unsigned long apicid_to_phys_cpu_present(int apicid)
 {
+	int shift_len;
+
+	shift_len = apicid;
 	if(clustered_apic_mode)
-		return 1UL << (((apicid >> 4) << 2) + (apicid & 0x3));
-	return 1UL << apicid;
+		shift_len = ((apicid >> 4) << 2) + (apicid & 0x3);
+
+	return shift_len >= sizeof(unsigned long) ? 0 : 1UL << shift_len;
 }
 
 #define physical_to_logical_apicid(phys_apic) ( (1ul << (phys_apic & 0x3)) | (phys_apic & 0xF0u) )