diff --git a/cpu/riscv.c b/cpu/riscv.c
index ed92202..4c7c4bd 100644
--- a/cpu/riscv.c
+++ b/cpu/riscv.c
@@ -698,6 +698,7 @@ int riscv_init(riscv_t* riscv, uint32_t* rom, uint32_t rom_addr_base, uint32_t r
   riscv->rom_size = rom_size;
   riscv->rom_addr_base = rom_addr_base;
   riscv->pc = riscv->rom_addr_base;
+  riscv->ra = 0xffffffff;
   return 0;
 }
 
@@ -732,8 +733,8 @@ int riscv_irq_check(riscv_t* riscv) {
         irq_num = 11;
       }
       riscv->mtval = 0;
-      riscv_enter_trap(riscv, 1, irq_num);
       if (irq_num>0) {
+        riscv_enter_trap(riscv, 1, irq_num);
         riscv->mip &= ~(1 << irq_num);
         irq_num = 0;
       }
@@ -746,15 +747,14 @@ int riscv_run(riscv_t* riscv) {
   int ret = 0;
   uint32_t pc;
   while (1) {
-    if (riscv->pc == 0) {
+    if (riscv->pc == 0xfffffffe && riscv->ra == 0xffffffff) {
       break;
     }
     if (riscv->pc >= riscv->rom_addr_base + riscv->rom_size || riscv->pc < riscv->rom_addr_base) {
       // 指令访问失败
       riscv->mtval = riscv->pc;
-      printf("riscv run out of rom pc=%08x\n",riscv->pc);
+      // printf("riscv run out of rom pc=%08x\n",riscv->pc);
       riscv_enter_trap(riscv, 0, 1);
-      printf("riscv run out of rom pc=%08x\n",riscv->pc);
     }
     if (riscv->pc & 0x3) {
       // 指令地址未对齐
diff --git a/riscv/interrupt.c b/riscv/interrupt.c
index a5e7fdf..f28d854 100644
--- a/riscv/interrupt.c
+++ b/riscv/interrupt.c
@@ -7,7 +7,72 @@ void interrupt_entry(uint32_t irq_num) {
   my_printf("interrupt_entry %d\n", irq_num);
 }
 
-void trap_entry(uint32_t irq_num) {
-  my_printf("trap_entry %d\n", irq_num);
-  write_csr(mscratch, 0xffffffff);
+
+
+static const char *g_fault_cause[]={
+  "Instruction address misaligned",// 0
+  "Instruction access fault",// 1
+  "Illegal instruction",// 2
+  "Breakpoint",// 3
+  "Load address misaligned",// 4
+  "Load access fault",// 5
+  "Store address misaligned",// 6
+  "Store access fault",// 7
+  "Environment call from U-mode",// 8
+  "Environment call from S-mode",// 9
+  "",
+  "Environment call from M-mode",// 11
+  "Instruction page fault",// 12
+  "Load page fault",// 13
+  "",
+  "Store page fault",// 15
+};
+
+
+
+
+void trap_entry(uint32_t irq_num, stack_context *stack) {
+  my_printf("fault reason is %s\n", g_fault_cause[irq_num]);
+  my_printf("x1(ra):    %08x\n", stack->ra);
+  my_printf("x2(sp):    %08x\n", stack->sp);
+  my_printf("x3(gp):    %08x\n", stack->gp);
+  my_printf("x4(tp):    %08x\n", stack->tp);
+  my_printf("x5(t0):    %08x\n", stack->t0);
+  my_printf("x6(t1):    %08x\n", stack->t1);
+  my_printf("x7(t2):    %08x\n", stack->t2);
+  my_printf("x8(s0|fp): %08x\n", stack->s0);
+  my_printf("x9(s1):    %08x\n", stack->s1);
+  my_printf("x10(a0):   %08x\n", stack->a0);
+  my_printf("x11(a1):   %08x\n", stack->a1);
+  my_printf("x12(a2):   %08x\n", stack->a2);
+  my_printf("x13(a3):   %08x\n", stack->a3);
+  my_printf("x14(a4):   %08x\n", stack->a4);
+  my_printf("x15(a5):   %08x\n", stack->a5);
+  my_printf("x16(a6):   %08x\n", stack->a6);
+  my_printf("x17(a7):   %08x\n", stack->a7);
+  my_printf("x18(s2):   %08x\n", stack->s2);
+  my_printf("x19(s3):   %08x\n", stack->s3);
+  my_printf("x20(s4):   %08x\n", stack->s4);
+  my_printf("x21(s5):   %08x\n", stack->s5);
+  my_printf("x22(s6):   %08x\n", stack->s6);
+  my_printf("x23(s7):   %08x\n", stack->s7);
+  my_printf("x24(s8):   %08x\n", stack->s8);
+  my_printf("x25(s9):   %08x\n", stack->s9);
+  my_printf("x26(s10):  %08x\n", stack->s10);
+  my_printf("x27(s11):  %08x\n", stack->s11);
+  my_printf("x28(t3):   %08x\n", stack->t3);
+  my_printf("x29(t4):   %08x\n", stack->t4);
+  my_printf("x30(t5):   %08x\n", stack->t5);
+  my_printf("x31(t6):   %08x\n", stack->t6);
+  my_printf("mstatus:   %08x\n", stack->mstatus);
+  my_printf("mepc:      %08x\n", stack->mepc);
+  my_printf("mtval:     %08x\n", read_csr(mtval));
+
+  // 函数调用错误，直接跳过这个函数
+  if(irq_num==1){
+    my_printf("skip the function call, return to %08x\n", stack->ra);
+    stack->mepc = stack->ra;
+  }
+
+  // write_csr(mscratch, 0xffffffff);
 }
diff --git a/riscv/main.c b/riscv/main.c
index 6b2a9a1..ed9b092 100644
--- a/riscv/main.c
+++ b/riscv/main.c
@@ -44,13 +44,15 @@ int main()
 {
   int a=1;
   int b=2;
-  // typedef void (*fun_t)(void);
-  // fun_t fun = (fun_t)0xffffffff;
-  // fun();
+  typedef void (*fun_t)(void);
+  fun_t fun = (fun_t)0;
+  fun();
   int c = add(a, b);
   my_printf("Hello World! %s\n", "Andy");
   my_printf("add(%d, %d)=%d\n", a, b, c);
   a = 67;b = -78;
+  fun=(fun_t)0xff000000;
+  fun();
   my_printf("mul(%d, %d)=%d\n", a, b, a * b);
   my_printf("ram_val test: %s\n", g_string);
   set_csr(mstatus, 0x00000008);
diff --git a/riscv/trap.S b/riscv/trap.S
index c83e5d7..9f7f67b 100644
--- a/riscv/trap.S
+++ b/riscv/trap.S
@@ -82,10 +82,11 @@
 
 # .section .interrupt.text
 .extern trap_entry
-.global trap_entry_
+.global _trap_entry
 .align 4
-trap_entry_:
+_trap_entry:
     csrw  mscratch, sp
+    mv    a1, sp
     la    sp, _exc_sp
     call  trap_entry
     csrr  sp, mscratch
@@ -106,7 +107,7 @@ trap_handler:
     li    a2, 0x000000ff
     and   a1, a0, a1
     and   a0, a2, a0
-    beqz  a1, trap_entry_
+    beqz  a1, _trap_entry
     csrw  mscratch, sp
     la    sp, _irq_sp
     call   interrupt_entry