diff --git a/doc/funcref.sgml b/doc/funcref.sgml
index bfd687b6f..f995d2982 100644
--- a/doc/funcref.sgml
+++ b/doc/funcref.sgml
@@ -578,6 +578,12 @@ communication, see also <tt>testcode/lib/ser-test.c</tt>.
 <item><ref id="signal" name="signal">
 </itemize>
 
+<sect1><tt/specialmath.h/<label id="specialmath.h"><p>
+
+<itemize>
+<item><ref id="_mul20" name="_mul20">
+<item><ref id="_mul40" name="_mul40">
+</itemize>
 
 <sect1><tt/stdarg.h/<label id="stdarg.h"><p>
 
@@ -1020,6 +1026,29 @@ It returns 1 if it does.
 </descrip>
 </quote>
 
+<sect1>_mul20<label id="_mul20"><p>
+
+<quote>
+<descrip>
+<tag/Function/Multiplies argument by 20.
+<tag/Header/<tt/<ref id="specialmath.h" name="specialmath.h">/
+<tag/Declaration/<tt/unsigned int __fastcall__ _mul20(unsigned char value);/
+<tag/Description/Speed optimized function to multiply an 8 bit unsigned value by 20 to get a 16 bit result.
+<tag/Availability/cc65
+</descrip>
+</quote>
+
+<sect1>_mul40<label id="_mul40"><p>
+
+<quote>
+<descrip>
+<tag/Function/Multiplies argument by 40.
+<tag/Header/<tt/<ref id="specialmath.h" name="specialmath.h">/
+<tag/Declaration/<tt/unsigned int __fastcall__ _mul40(unsigned char value);/
+<tag/Description/Speed optimized function to multiply an 8 bit unsigned value by 40 to get a 16 bit result.
+<tag/Availability/cc65
+</descrip>
+</quote>
 
 <sect1>_poserror<label id="_poserror"><p>
 
diff --git a/doc/index.sgml b/doc/index.sgml
index 55e69f40f..aecfb7de9 100644
--- a/doc/index.sgml
+++ b/doc/index.sgml
@@ -97,9 +97,6 @@
   Describes Christian Kr&uuml;ger's macro package for writing self modifying
   assembler code.
 
-  <tag><htmlurl url="specialmath.html" name="specialmath.html"></tag>
-  Library for speed optimized math functions.  
-
   <tag><url name="6502 Binary Relocation Format document"
         url="http://www.6502.org/users/andre/o65/fileformat.html"></tag>
   Describes the o65 file format that is used for dynamically loadable modules
diff --git a/doc/specialmath.sgml b/doc/specialmath.sgml
deleted file mode 100644
index 5e2fd90a7..000000000
--- a/doc/specialmath.sgml
+++ /dev/null
@@ -1,38 +0,0 @@
-<!doctype linuxdoc system>
-
-<article>
-<title>Special math functions
-<author>Christian Kr&uuml;ger
-
-<abstract>
-This library provides functions for speed optimized math operations.
-</abstract>
-
-<!-- Table of contents -->
-<toc>
-
-<!-- Begin the document -->
-
-<sect>Multiplication<p>
-
-When accessing screen memory often a multiplication of the vertical position is needed to calculate
-the target address. A quite common horizontal span for 8-bit systems is 20 or 40 bytes (beside e.g. 32 bytes, where the multiplication can be accomplished by shifting 5 times).
-
-<p>
-<tscreen><verb>
-    unsigned int __fastcall__ _mul20(unsigned char value);
-</verb></tscreen>
-
-The 8 bit <tt>value</tt> is multiplied by 20 and returned as 16 bit value.
-</p>
-
-<p>
-<tscreen><verb>
-    unsigned int __fastcall__ _mul40(unsigned char value);
-</verb></tscreen>
-
-The 8 bit <tt>value</tt> is multiplied by 40 and returned as 16 bit value.
-</p>
-
-
-</article>