diff --git a/src/libsys/boards/denano/board.c b/src/libsys/boards/denano/board.c
index 1e0df4f..9bd8b0a 100644
--- a/src/libsys/boards/denano/board.c
+++ b/src/libsys/boards/denano/board.c
@@ -8,6 +8,8 @@
 #include "board.h"
 #include "../../regdef.h"
 
+#define DEBUGGER	gdb_stub
+
 extern uart_if_t uart_if[];
 
 #define ARRAYSIZE(a)	(sizeof(a)/sizeof(a[0]))
@@ -47,7 +49,7 @@ void dbg_uart_isr(struct xcptcontext *xcp)
 		char c = *dbg_uart->pDATA;
 		if (c == 3)
 		{
-			gdb_stub(xcp);
+			DEBUGGER(xcp);
 		}
 	}
 }
@@ -98,7 +100,14 @@ char dbg_getchar()
 
 void dbg_init()
 {
-	xcpt_register(EXC_BP, gdb_stub);
+	xcpt_register(EXC_ADEL, DEBUGGER);
+	xcpt_register(EXC_ADES, DEBUGGER);
+	xcpt_register(EXC_IBE, DEBUGGER);
+	xcpt_register(EXC_DBE, DEBUGGER);
+	xcpt_register(EXC_BP, DEBUGGER);
+	xcpt_register(EXC_RI, DEBUGGER);
+	xcpt_register(EXC_CPU, DEBUGGER);
+	xcpt_register(EXC_OV, DEBUGGER);
 }
 
 void board_init(void)
diff --git a/src/libsys/gdb_stub.c b/src/libsys/gdb_stub.c
index 75f971e..2d6a48a 100644
--- a/src/libsys/gdb_stub.c
+++ b/src/libsys/gdb_stub.c
@@ -402,6 +402,11 @@ hexToInt(char **ptr, unsigned long *intValue)
 	return (numChars);
 }
 
+int isBreak(unsigned long instr)
+{
+	return ((instr & 0xFC00003F) == 0x0000000D);
+}
+
 /*
  * This function does all command procesing for interfacing to gdb.  It
  * returns 1 if you should skip the instruction at the trap address, 0
@@ -417,9 +422,11 @@ handle_exception (unsigned long *registers)
 	unsigned long length;
 	char *ptr;
 	unsigned long *sp;
-
-	// branch shadow
-	if (registers[CR] & 0x80000000)
+	
+	unsigned long *pAddr = (unsigned long *)registers[PC];
+	
+	// is break
+	if (isBreak(*pAddr))
 	{
 		registers[PC] += 4;
 	}