added

[rrq/rrqforth.git] / adoc / p_roll.adoc

diff --git a/adoc/p_roll.adoc b/adoc/p_roll.adoc
index 79083f26a9dda91f03e3538ee406ba3d56aa81ab..a4d4419967d281e02f25acdda91aa04f68bc6388 100644 (file)
--- a/adoc/p_roll.adoc
+++ b/adoc/p_roll.adoc
@@ -1,9 +1,19 @@
+// stack.asm:  WORD p_roll, 'ROLL',fasm
+
 anchor:p_roll[]
 
-Word: ROLL
-----------
+=== Word: ROLL
+
+....
+Data stack: ( vu...v1 v0 u -- ...v1 v0 vu )
+....
+
+"ROLL" is a function word that "moves" the u:th data stack cell down
+from top onto the data stack while discarding it. 0 indicates the top
+cell; 1 indicates the second top cell making it the same as
+<<p_swap,SWAP>>; 2 indicates the third top cell making it the same as
+<<p_rot,ROT>>.
+
+
 
-----
-stack.asm:     WORD p_roll, 'ROLL',fasm
-----