diff --git a/runtime/doc/syntax.txt b/runtime/doc/syntax.txt
index 23eed7e..3745f32 100644
--- a/runtime/doc/syntax.txt
+++ b/runtime/doc/syntax.txt
@@ -650,7 +650,11 @@ The most flexible is to add a line in your assembly file containing: >
 	asmsyntax=nasm
 Replace "nasm" with the name of the real assembly syntax.  This line must be
 one of the first five lines in the file.  No non-white text must be
-immediately before or after this text.
+immediately before or after this text.  Note that specifying asmsyntax=foo is
+equivalent to setting ft=foo in a |modeline|, and that in case of a conflict
+between the two settings the one from the modeline will take precedence (in
+particular, if you have ft=asm in the modeline, you will get the GNU syntax
+highlighting regardless of what is specified as asmsyntax).
 
 The syntax type can always be overruled for a specific buffer by setting the
 b:asmsyntax variable: >