diff --git a/am/Makefile b/am/Makefile
index 9dbb61c4..ac8efe4b 100644
--- a/am/Makefile
+++ b/am/Makefile
@@ -1,3 +1,4 @@
 NAME = am
 SRCS = $(shell find -L ./arch/$(ARCH)/src/ -name "*.c" -o -name "*.cpp" -o -name "*.S")
+LIBS += klib
 include $(AM_HOME)/Makefile.lib
diff --git a/am/arch/mips32-npc/include/npc.h b/am/arch/mips32-npc/include/npc.h
index 33257019..bec69f09 100644
--- a/am/arch/mips32-npc/include/npc.h
+++ b/am/arch/mips32-npc/include/npc.h
@@ -14,6 +14,23 @@
 #define HZ 50000000
 #define MAX_MEMORY_SIZE 0x4000000
 #define INTERVAL 1000
+   
+#define cp0_badvaddr 8
+#define cp0_count    9
+#define cp0_compare  11
+#define cp0_status   12
+#define cp0_cause    13
+#define cp0_epc      14
+
+#define MFC0(dst, src, sel) \
+asm volatile("mfc0 %0, $"_STR(src)", %1\n\t":"=r"(dst):"i"(sel))
+
+#define MTC0(dst, src, sel) \
+asm volatile("mtc0 %0, $"_STR(dst)", %1\n\t"::"g"(src),"i"(sel))
+
+#define _STR(x) _VAL(x)
+#define _VAL(x) #x
+
 
 static inline u8 R(_Pixel p) { return p >> 16; }
 static inline u8 G(_Pixel p) { return p >> 8; }
diff --git a/am/arch/mips32-npc/src/asym.c b/am/arch/mips32-npc/src/asym.c
index 9d63e570..4734af5f 100644
--- a/am/arch/mips32-npc/src/asym.c
+++ b/am/arch/mips32-npc/src/asym.c
@@ -1,20 +1,21 @@
 #include <am.h>
 #include <npc.h>
 #include <arch.h>
+#include <klib.h>
 
 u32 GetCount(int sel){
   u32 tick = 0;
-  if(sel == 1)
-    asm volatile("mfc0 %0, $9, %1\n\t":"=r"(tick):"i"(1));
-  else if(sel == 0)
-    asm volatile("mfc0 %0, $9, %1\n\t":"=r"(tick):"i"(0));
+  if(sel == 0)
+    MFC0(tick, cp0_count, 0);
+  else if(sel == 1)
+    MFC0(tick, cp0_count, 1);
   else
     _halt(1);
   return tick;
 }
 
 void SetCompare(u32 compare){
-  asm volatile("mtc0 %0, $11\n\t"::"r"(compare));
+  MTC0(cp0_compare, compare, 0);
 }
 
 void _time_event(){
@@ -40,21 +41,21 @@ void _idle(){
 
 void _idisable(){
   int status = 0;
-  asm volatile("mfc0 %0,$12	\n\t":"=r"(status));
+  MFC0(status, cp0_status, 0);
   status = status | 0x2;
-  asm volatile("mtc0 %0,$12	\n\t"::"r"(status));
+  MTC0(cp0_status, status, 0);  
 }
 
 void _ienable(){
   int status = 0;
-  asm volatile("mfc0 %0,$12	\n\t":"=r"(status));
+  MFC0(status, cp0_status, 0);
   status = status & 0xfffffffd;
-  asm volatile("mtc0 %0,$12	\n\t"::"r"(status));
+  MTC0(cp0_status, status, 0);  
 }
 
 int _istatus(){
   int status = 0;
-  asm volatile("mfc0 %0,$12	\n\t":"=r"(status));
+  MFC0(status, cp0_status, 0);
   if((status & 0x2) >> 1){
     return 0;
   }
@@ -65,19 +66,22 @@ int _istatus(){
 
 void irq_handle(struct TrapFrame *tf){
 //TODO:handle interrupt
-  u32 arg = 0;
-  u32 intr = 0;
-  u8  IPCode = 0;
-  u8  ExcCode = 0;
-  u32 EPC = 0;
-  u32 BadVaddr = 0;
+  u32 arg = 0, IPExcCode = 0;
+  u8  IPCode = 0, ExcCode = 0;
+  u32 EPC = 0, BadVaddr = 0;
+
+  // cp0 info & general regfiles, values of k0 & k1 come from trap.S
   asm volatile("add %0,$k1,$zero\n\t":"=r"(arg));
-  asm volatile("add %0,$k0,$zero\n\t":"=r"(intr));
-  asm volatile("mfc0 %0, $14\n\t":"=r"(EPC));
-  asm volatile("mfc0 %0, $8\n\t":"=r"(BadVaddr));
+  asm volatile("add %0,$k0,$zero\n\t":"=r"(IPExcCode));
+  MFC0(EPC, cp0_epc, 0);
+  MFC0(BadVaddr, cp0_badvaddr, 0);
+  
   tf = (void *)arg;
-  IPCode = (intr & 0xff00) >> 8;
-  ExcCode = (intr & 0xff) >> 2;
+  IPCode = (IPExcCode & 0xff00) >> 8;
+  ExcCode = (IPExcCode & 0xff) >> 2;
+  
+
+  //TODO: exception handling
   switch(ExcCode){
     case 0:{ //interrupt
       switch(IPCode){
@@ -107,32 +111,36 @@ void irq_handle(struct TrapFrame *tf){
     }
     break;
     case 8:{ // syscall
-      printk("syscall\n");
+      printk("Syscall\n");
+      printk("$epc = 0x%x\n", EPC);
+      // epc + 4 -> used to eret to next instruction, instead of syscall
       EPC += 4;
-      asm volatile("mtc0 %0, $14\n\t"::"g"(EPC));
+      MTC0(cp0_epc, EPC, 0);
+      _halt(0);
     }
     break;
     case 9:{ // breakpoint
       printk("Break\n");
-      EPC += 4;
-      asm volatile("mtc0 %0, $14\n\t"::"g"(EPC));
+      printk("$epc = 0x%x\n", EPC);
+     _halt(0); 
     }
     break;
     case 10:{ // invalid instruction
       printk("Invalid instruction\n");
+      printk("$epc = 0x%x\n", EPC);
       _halt(0);
     }
     break;
     case 12:{ // overflow
       printk("Overflow\n");
-      EPC += 4;
-      asm volatile("mtc0 %0, $14\n\t"::"g"(EPC));
+      printk("$epc = 0x%x\n", EPC);
+      _halt(0);
     }
     break;
     case 13:{ // trap
       printk("Trap\n");
       EPC += 4;
-      asm volatile("mtc0 %0, $14\n\t"::"g"(EPC));
+      MTC0(cp0_epc, EPC, 0);
       _halt(0);
     }
     break;