The code generator

From Lazarus wiki
Revision as of 22:22, 20 December 2003 by FPK (talk | contribs)
Jump to navigationJump to search

With the version 1.9.x of FPC the code generator has been completly rewritten to fit the needs of a compiler with multiple processor target support.


MM support

The FPC code generator supports the usage of multimedia registers as the are implemented by modern processors.

The shuffle operand

Most multimedia units supports scalar as well as vector operations on the multimedia registers. To distinguish between these different operations, the mm methods of tcg take a so called shuffle parameter. This parameter allows to specify how the data is processed when generating multimedia code.

 pmmshuffle = ^tmmshuffle;  
 { this record describes shuffle operations for mm operations; if a pointer a shuffle record
   passed to an mm operation is nil, it means that the whole location is moved }
 tmmshuffle = record
   { describes how many shuffles are actually described, if len=0 then
     moving the scalar with index 0 to the scalar with index 0 is meant }
   len : byte;
   { lower nibble of each entry of this array describes index of the source data index while
     the upper nibble describes the destination index }
   shuffles : array[1..1] of byte;
 end;