1 <!doctype linuxdoc system>
4 <title>Special math functions
5 <author>Christian Krüger
8 This library provides functions for speed optimized math operations.
11 <!-- Table of contents -->
14 <!-- Begin the document -->
16 <sect>Multiplication<p>
18 When accessing screen memory often a multiplication of the vertical position is needed to calculate
19 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).
23 unsigned int __fastcall__ mul20(unsigned char value);
26 The 8 bit <tt>value</tt> is multiplied by 20 and returned as 16 bit value.
31 unsigned int __fastcall__ mul40(unsigned char value);
34 The 8 bit <tt>value</tt> is multiplied by 40 and returned as 16 bit value.