diff --git a/src/arch/arm/exception.c b/src/arch/arm/exception.c
index 2e6b3e5..9804749 100644
--- a/src/arch/arm/exception.c
+++ b/src/arch/arm/exception.c
@@ -18,7 +18,7 @@
 #include INC_SUBARCH(mm.h)
 
 /* Abort debugging conditions */
-// #define DEBUG_ABORTS
+ #define DEBUG_ABORTS
 #if defined (DEBUG_ABORTS)
 #define dbg_abort(...)	dprintk(__VA_ARGS__)
 #else
diff --git a/tasks/libl4/src/arm/exregs.c b/tasks/libl4/src/arm/exregs.c
index 1c7f138..72928e5 100644
--- a/tasks/libl4/src/arm/exregs.c
+++ b/tasks/libl4/src/arm/exregs.c
@@ -21,8 +21,7 @@ void exregs_set_mr(struct exregs_data *s, int offset, unsigned long val)
 	mr[offset] = val;
 
 	/* Set valid bit for mr register */
-	s->valid_vect |= offsetof(exregs_context_t, r3) +
-			 (offset * sizeof(int));
+	s->valid_vect |= FIELD_TO_BIT(exregs_context_t, r3) << offset;
 }
 
 void exregs_set_pager(struct exregs_data *s, l4id_t pagerid)
@@ -34,12 +33,12 @@ void exregs_set_pager(struct exregs_data *s, l4id_t pagerid)
 void exregs_set_stack(struct exregs_data *s, unsigned long sp)
 {
 	s->context.sp = sp;
-	s->valid_vect |= 1 << (offsetof(exregs_context_t, sp) >> 2);
+	s->valid_vect |= FIELD_TO_BIT(exregs_context_t, sp);
 }
 
 void exregs_set_pc(struct exregs_data *s, unsigned long pc)
 {
 	s->context.pc = pc;
-	s->valid_vect |= 1 << (offsetof(exregs_context_t, pc) >> 2);
+	s->valid_vect |= FIELD_TO_BIT(exregs_context_t, pc);
 }