diff --git a/runtime/doc/builtin.txt b/runtime/doc/builtin.txt
index 3544b5d..a888ae0 100644
--- a/runtime/doc/builtin.txt
+++ b/runtime/doc/builtin.txt
@@ -7966,7 +7966,7 @@
 		{low} and {high} can be the same, in which case this refers to
 		one character.  Otherwise it is the range of characters from
 		{low} to {high} (inclusive).		*E1111* *E1114*
-		Only characters with value 0x100 and higher can be used.
+		Only characters with value 0x80 and higher can be used.
 
 		{width} must be either 1 or 2, indicating the character width
 		in screen cells.			*E1112*