diff --git a/sys/mips/include/regnum.h b/sys/mips/include/regnum.h
index dc0b7f37f948..f94ed6c70218 100644
--- a/sys/mips/include/regnum.h
+++ b/sys/mips/include/regnum.h
@@ -125,7 +125,7 @@
 
 /*
  * Pseudo registers so we save a complete set of registers regardless of
- * the ABI
+ * the ABI. See regdef.h for a more complete explanation.
  */
 #if defined(__mips_n32) || defined(__mips_n64)
 #define	TA0	8