diff --git a/software/libbase/crt0-or1k.S b/software/libbase/crt0-or1k.S
index 6a5914e5b..33807f87b 100644
--- a/software/libbase/crt0-or1k.S
+++ b/software/libbase/crt0-or1k.S
@@ -19,7 +19,7 @@
 
 #include <spr-defs.h>
 
-#define EXCEPTION_STACK_SIZE (128+128)
+#define EXCEPTION_STACK_SIZE (4*32)
 
 #define HANDLE_EXCEPTION                    ; \
     l.addi  r1, r1, -EXCEPTION_STACK_SIZE   ; \
@@ -193,11 +193,18 @@ _exception_handler:
 
     /* Save return address */
     l.or    r14, r0, r9
-    /* send stack pointer as argument */
+    /* Calculate exception vector from handler address */
+    l.andi  r3, r9, 0xf00
+    l.srli  r3, r3, 8
+    /* Pass saved register state */
     l.or    r4, r0, r1
+    /* Extract exception PC */
+    l.mfspr r5, r0, SPR_EPCR_BASE
+    /* Extract exception effective address */
+    l.mfspr r6, r0, SPR_EEAR_BASE
     /* Call exception handler with the link address as argument */
     l.jal   exception_handler
-     l.or   r3, r0, r14
+     l.nop
 
     /* Load return address */
     l.or    r9, r0, r14
diff --git a/software/libbase/exception.c b/software/libbase/exception.c
index 73454e32d..542001ad8 100644
--- a/software/libbase/exception.c
+++ b/software/libbase/exception.c
@@ -2,12 +2,14 @@ void isr(void);
 
 #ifdef __or1k__
 
-#define EXTERNAL_IRQ 0x800
+#define EXTERNAL_IRQ 0x8
 
-void exception_handler(unsigned long vect, unsigned long *sp);
-void exception_handler(unsigned long vect, unsigned long *sp)
+void exception_handler(unsigned long vect, unsigned long *regs,
+                       unsigned long pc, unsigned long ea);
+void exception_handler(unsigned long vect, unsigned long *regs,
+                       unsigned long pc, unsigned long ea)
 {
-	if((vect & 0xf00) == EXTERNAL_IRQ) {
+	if(vect == EXTERNAL_IRQ) {
 		isr();
 	} else {
 		/* Unhandled exception */