1 files changed, 3 insertions, 0 deletions

diff --git a/readme.md b/readme.md
index 0e9e694..c2cc91a 100644
--- a/readme.md
+++ b/readme.md
@@ -632,6 +632,9 @@ yield the address of the return pointer.
 note that the address points to the return stack *before*
 this word was called.
 
+### `rp0   ( -- a )`
+a variable containing the value of the return stack at the beginning of the program.
+
 ### `s"   ( "string" -- , COMPILES: -- a u ) IMMEDIATE COMPILE-ONLY`
 compile into the definition code to push the given string,
 terminated by a double quote.