diff --git a/.gitignore b/.gitignore
index 92fc6e7..1a75fcc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,3 +50,6 @@ build-aux/
 /doc/mach.toc
 /doc/mach.tp
 /doc/mach.vr
+/build
+Makefile.am.orig
+Makefile.am.rej
diff --git a/Makefrag.am b/Makefrag.am
index 4625b48..8b855cb 100644
--- a/Makefrag.am
+++ b/Makefrag.am
@@ -139,6 +139,7 @@ libkernel_a_SOURCES += \
 	kern/counters.c \
 	kern/counters.h \
 	kern/cpu_number.h \
+	kern/cpu_number.c \
 	kern/debug.c \
 	kern/debug.h \
 	kern/eventcount.c \
diff --git a/configfrag.ac b/configfrag.ac
index 3d7033e..d1fe101 100644
--- a/configfrag.ac
+++ b/configfrag.ac
@@ -32,7 +32,7 @@ AC_DEFINE([BOOTSTRAP_SYMBOLS], [0], [BOOTSTRAP_SYMBOLS])
 
 # Multiprocessor support is still broken.
 AH_TEMPLATE([MULTIPROCESSOR], [set things up for a uniprocessor])
-mach_ncpus=1
+mach_ncpus=2
 AC_DEFINE_UNQUOTED([NCPUS], [$mach_ncpus], [number of CPUs])
 [if [ $mach_ncpus -gt 1 ]; then]
   AC_DEFINE([MULTIPROCESSOR], [1], [set things up for a multiprocessor])
diff --git a/cpu_number.c b/cpu_number.c
new file mode 100644
index 0000000..0b2e2f1
--- /dev/null
+++ b/cpu_number.c
@@ -0,0 +1,28 @@
+int apic2kernel[255];
+int cpu_number_start = 0, cpu_number_counter = 0;
+
+int cpu_number(void) {
+  int eax = 1, ebx = 0, ecx = 0, edx = 0;
+  unsigned int i = 0;
+  int apic_id = 0;
+
+  if (!cpu_number_start) {
+    for (i = 0; i < 255; i++) {
+      apic2kernel[i] = -1;
+    }
+    cpu_number_start = 1;
+  }
+
+  asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (eax));
+  apic_id = (char) (ebx >> 24) & 0xff;
+  //printf("apic_id = %d\n", apic_id);
+
+  if (apic2kernel[apic_id] != -1) {
+    return apic2kernel[apic_id];
+  } else {
+    apic2kernel[apic_id] = cpu_number_counter;
+    cpu_number_counter++;
+  }
+
+  return apic2kernel[apic_id];
+}
diff --git a/i386/i386/cpu_number.S b/i386/i386/cpu_number.S
new file mode 100644
index 0000000..95036b8
--- /dev/null
+++ b/i386/i386/cpu_number.S
@@ -0,0 +1,4 @@
+.macro CPU_NUMBER reg
+ call cpu_number
+ movl %eax, \reg
+.endm
diff --git a/i386/i386/cswitch.S b/i386/i386/cswitch.S
index 718c8aa..970255a 100644
--- a/i386/i386/cswitch.S
+++ b/i386/i386/cswitch.S
@@ -29,6 +29,7 @@
 #include <i386/proc_reg.h>
 #include <i386/i386asm.h>
 #include <i386/cpu_number.h>
+.include  "i386/cpu_number.S"
 
 /*
  * Context switch routines for i386.
@@ -39,7 +40,7 @@ ENTRY(Load_context)
 	movl	TH_KERNEL_STACK(%ecx),%ecx	/* get kernel stack */
 	lea	KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%edx
 						/* point to stack top */
-	CPU_NUMBER(%eax)
+	CPU_NUMBER %eax
 	movl	%ecx,CX(EXT(active_stacks),%eax)	/* store stack address */
 	movl	%edx,CX(EXT(kernel_stack),%eax)	/* store stack top */
 
@@ -57,7 +58,7 @@ ENTRY(Load_context)
  */
 
 ENTRY(Switch_context)
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	movl	CX(EXT(active_stacks),%edx),%ecx	/* get old kernel stack */
 
 	movl	%ebx,KSS_EBX(%ecx)		/* save registers */
@@ -109,7 +110,7 @@ ENTRY(Thread_continue)
  * has no FPU state)
  */
 ENTRY(switch_to_shutdown_context)
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	movl	EXT(active_stacks)(,%edx,4),%ecx	/* get old kernel stack */
 	movl	%ebx,KSS_EBX(%ecx)		/* save registers */
 	movl	%ebp,KSS_EBP(%ecx)
diff --git a/i386/i386/locore.S b/i386/i386/locore.S
index ddba224..265a5d1 100644
--- a/i386/i386/locore.S
+++ b/i386/i386/locore.S
@@ -37,6 +37,7 @@
 #include <i386/i386asm.h>
 #include <i386/cpu_number.h>
 #include <i386/xen.h>
+.include "i386/cpu_number.S"
 
 /*
  * Fault recovery.
@@ -243,7 +244,7 @@ timer_normalize:
  * Switch to a new timer.
  */
 ENTRY(timer_switch)
-	CPU_NUMBER(%edx)			/* get this CPU  */
+	CPU_NUMBER %edx			/* get this CPU  */
 	movl	VA_ETC,%ecx			/* get timer */
 	movl	CX(EXT(current_tstamp),%edx),%eax	/* get old time stamp  */
 	movl	%ecx,CX(EXT(current_tstamp),%edx)	/* set new time stamp */
@@ -261,7 +262,7 @@ ENTRY(timer_switch)
  * Initialize the first timer for a CPU.
  */
 ENTRY(start_timer)
-	CPU_NUMBER(%edx)			/* get this CPU */
+	CPU_NUMBER %edx			/* get this CPU */
 	movl	VA_ETC,%ecx			/* get timer */
 	movl	%ecx,CX(EXT(current_tstamp),%edx)	/* set initial time stamp */
 	movl	S_ARG0,%ecx			/* get timer */
@@ -479,7 +480,7 @@ trap_set_segs:
 	jz	trap_from_kernel	/* kernel trap if not */
 trap_from_user:
 
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	TIME_TRAP_UENTRY
 
 	movl	CX(EXT(kernel_stack),%edx),%ebx
@@ -501,7 +502,7 @@ _take_trap:
  */
 
 _return_from_trap:
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	cmpl	$0,CX(EXT(need_ast),%edx)
 	jz	_return_to_user		/* if we need an AST: */
 
@@ -547,7 +548,7 @@ trap_from_kernel:
 	cmpl	EXT(int_stack_base),%edx
 	je	1f			/* OK if so */
 
-	CPU_NUMBER(%edx)		/* get CPU number */
+	CPU_NUMBER %edx		/* get CPU number */
 	cmpl	CX(EXT(kernel_stack),%edx),%esp
 					/* already on kernel stack? */
 	ja	0f
@@ -664,7 +665,7 @@ ENTRY(all_intrs)
 	mov	%dx,%fs
 	mov	%dx,%gs
 
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 
 	movl	CX(EXT(int_stack_top),%edx),%ecx
 	xchgl	%ecx,%esp		/* switch to interrupt stack */
@@ -683,7 +684,7 @@ ENTRY(all_intrs)
 	.globl	EXT(return_to_iret)
 LEXT(return_to_iret)			/* ( label for kdb_kintr and hardclock) */
 
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 #if	STAT_TIME
 #else
 	TIME_INT_EXIT			/* do timing */
@@ -760,7 +761,7 @@ ast_from_interrupt:
 	mov	%dx,%fs
 	mov	%dx,%gs
 
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	TIME_TRAP_UENTRY
 
 	movl	CX(EXT(kernel_stack),%edx),%esp
@@ -1025,7 +1026,7 @@ syscall_entry_2:
 	movl	%edx,R_CS(%esp)		/* fix cs */
 	movl	%ebx,R_EFLAGS(%esp)	/* fix eflags */
 
-	CPU_NUMBER(%edx)
+	CPU_NUMBER %edx
 	TIME_TRAP_SENTRY
 
 	movl	CX(EXT(kernel_stack),%edx),%ebx
diff --git a/kern/cpu_number.c b/kern/cpu_number.c
new file mode 100644
index 0000000..0b2e2f1
--- /dev/null
+++ b/kern/cpu_number.c
@@ -0,0 +1,28 @@
+int apic2kernel[255];
+int cpu_number_start = 0, cpu_number_counter = 0;
+
+int cpu_number(void) {
+  int eax = 1, ebx = 0, ecx = 0, edx = 0;
+  unsigned int i = 0;
+  int apic_id = 0;
+
+  if (!cpu_number_start) {
+    for (i = 0; i < 255; i++) {
+      apic2kernel[i] = -1;
+    }
+    cpu_number_start = 1;
+  }
+
+  asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (eax));
+  apic_id = (char) (ebx >> 24) & 0xff;
+  //printf("apic_id = %d\n", apic_id);
+
+  if (apic2kernel[apic_id] != -1) {
+    return apic2kernel[apic_id];
+  } else {
+    apic2kernel[apic_id] = cpu_number_counter;
+    cpu_number_counter++;
+  }
+
+  return apic2kernel[apic_id];
+}
diff --git a/kern/cpu_number.h b/kern/cpu_number.h
index 5d3e4bd..2ea510e 100644
--- a/kern/cpu_number.h
+++ b/kern/cpu_number.h
@@ -37,7 +37,11 @@ int	master_cpu;	/* 'master' processor - keeps time */
 	/* cpu number is always 0 on a single processor system */
 #define	cpu_number()	(0)
 
-#endif	/* NCPUS == 1 */
+#else	/* NCPUS == 1 */
+
+extern int cpu_number(void);
+
+#endif /* NCPUS != 1 */
 
 #define CPU_L1_SIZE (1 << CPU_L1_SHIFT)