Editing 7z (section)

=== Pre-processing filters ===
The LZMA SDK comes with the [[BCJ (algorithm)|BCJ]] and [[BCJ2]] preprocessors included, so that later stages are able to achieve greater compression: For [[x86]], [[ARM architecture|ARM]], [[PowerPC]] (PPC), IA-64 [[Itanium]], and [[ARM Thumb]] processors, jump targets are "normalized"<ref name="lzma2_source_code" /> before compression by changing relative position into absolute values. For x86, this means that near jumps, calls and conditional jumps (but not short jumps and conditional jumps) are converted from the machine language "jump 1655 bytes backwards" style notation to normalized "jump to address 5554" style notation; all jumps to 5554, perhaps a common subroutine, are thus encoded identically, making them more compressible.

*[[BCJ (algorithm)|BCJ]]&nbsp;– Converter for 32-bit x86 executables. Normalises target addresses of near jumps and calls from relative distances to absolute destinations.
*[[BCJ2]]&nbsp;– Pre-processor for x86-64 executables. BCJ2 is an improvement on BCJ, adding additional x86 jump/call instruction processing.  Near jump, near call, conditional near jump targets are split out and compressed separately in another stream.
*[[Delta encoding]]&nbsp;– delta filter, basic preprocessor for multimedia data.

Similar executable pre-processing technology is included in other software; the [[RAR (file format)|RAR]] compressor features displacement compression for 32-bit x86 executables and IA-64 executables, and the [[UPX]] runtime executable file compressor includes support for working with 16-bit values within [[DOS]] binary files.