The code generator

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back to contents FPC internals

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 they are implemented by modern processors.

The shuffle operand

Most multimedia units support 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;