The code generator: what changed
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Title: The code generator
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| 1 | + | back to contents [[FPC internals]] | |
| 2 | + | ||
| 3 | + | 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. | |
| 4 | + | ||
| 5 | + | ## MM support | |
| 6 | + | ||
| 7 | + | The FPC code generator supports the usage of multimedia registers as they are implemented by modern processors. | |
| 8 | + | ||
| 9 | + | ### The shuffle operand | |
| 10 | + | ||
| 11 | + | 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. | |
| 12 | + | ||
| 13 | + | ``` pascal | |
| 14 | + | pmmshuffle = ^tmmshuffle; | |
| 15 | + | { this record describes shuffle operations for mm operations; if a pointer a shuffle record | |
| 16 | + | passed to an mm operation is nil, it means that the whole location is moved } | |
| 17 | + | tmmshuffle = record | |
| 18 | + | { describes how many shuffles are actually described, if len=0 then | |
| 19 | + | moving the scalar with index 0 to the scalar with index 0 is meant } | |
| 20 | + | len : byte; | |
| 21 | + | { lower nibble of each entry of this array describes index of the source data index while | |
| 22 | + | the upper nibble describes the destination index } | |
| 23 | + | shuffles : array[1..1] of byte; | |
| 24 | + | end; | |
| 25 | + | ``` | |
| 26 | + | ||
| 27 | + | --- | |
| 28 | + | *From the Free Pascal wiki, page "The code generator", as it stood on 2020-12-31 after a change by E-ric, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).* |