-#define SRCPROPFNAME(p) ((scm_srcprops *) SCM_CDR (p))->fname
-#define SRCPROPCOPY(p) ((scm_srcprops *) SCM_CDR (p))->copy
-#define SRCPROPPLIST(p) ((scm_srcprops *) SCM_CDR (p))->plist
-#define SETSRCPROPBRK(p) (SCM_SETOR_CAR (p, (1L << 16)))
-#define CLEARSRCPROPBRK(p) SCM_SETAND_CAR (p, ~(1L << 16))
+#define SRCPROPFNAME(p) ((scm_t_srcprops *) SCM_CELL_WORD_1 (p))->fname
+#define SRCPROPCOPY(p) ((scm_t_srcprops *) SCM_CELL_WORD_1 (p))->copy
+#define SRCPROPPLIST(p) ((scm_t_srcprops *) SCM_CELL_WORD_1 (p))->plist
+#define SETSRCPROPBRK(p) \
+ (SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) \
+ | SCM_SOURCE_PROPERTY_FLAG_BREAK))
+#define CLEARSRCPROPBRK(p) \
+ (SCM_SET_CELL_WORD_0 ((p), SCM_CELL_WORD_0 (p) \
+ & ~SCM_SOURCE_PROPERTY_FLAG_BREAK))