Commit Graph

14 Commits

Author SHA1 Message Date
Lasse Collin 5dcffdbcc2 liblzma: SHA-256: Optimize the Maj macro slightly.
The Maj macro is used where multiple things are added
together, so making Maj a sum of two expressions allows
some extra freedom for the compiler to schedule the
instructions.

I learned this trick from
<http://www.hackersdelight.org/corres.txt>.
2014-08-03 21:32:25 +03:00
Lasse Collin a9477d1e0c liblzma: SHA-256: Optimize the way rotations are done.
This looks weird because the rotations become sequential,
but it helps quite a bit on both 32-bit and 64-bit x86:

  - It requires fewer instructions on two-operand
    instruction sets like x86.

  - It requires one register less which matters especially
    on 32-bit x86.

I hope this doesn't hurt other archs.

I didn't invent this idea myself, but I don't remember where
I saw it first.
2014-08-03 21:08:12 +03:00
Lasse Collin 5a76c7c8ee liblzma: SHA-256: Remove the GCC #pragma that became unneeded.
The unrolling in the previous commit should avoid the
situation where a compiler may think that an uninitialized
variable might be accessed.
2014-08-03 20:38:13 +03:00
Lasse Collin 9a096f8e57 liblzma: SHA-256: Unroll a little more.
This way a branch isn't needed for each operation
to choose between blk0 and blk2, and still the code
doesn't grow as much as it would with full unrolling.
2014-08-03 20:33:38 +03:00
Lasse Collin bc7650d87b liblzma: SHA-256: Do the byteswapping without a temporary buffer. 2014-08-03 19:56:43 +03:00
Lasse Collin e28528f1c8 liblzma: Remove a useless C99ism from sha256.c.
Unsurprisingly it makes no difference in compiled output.
2014-01-12 12:50:30 +02:00
Lasse Collin ab22562066 A few typo fixes to comments and the xz man page.
Thanks to Jim Meyering.
2012-08-24 16:27:31 +03:00
Lasse Collin b34c5ce4b2 liblzma: Use TUKLIB_GNUC_REQ to check GCC version in sha256.c. 2011-04-05 22:41:33 +03:00
Lasse Collin ebfb2c5e1f Use a tuklib module for integer handling.
This replaces bswap.h and integer.h.

The tuklib module uses <byteswap.h> on GNU,
<sys/endian.h> on *BSDs and <sys/byteorder.h>
on Solaris, which may contain optimized code
like inline assembly.
2009-10-04 22:57:12 +03:00
Lasse Collin a6f43e6412 Use a GCC-specific #pragma instead of GCC-specific
-Wno-uninitialized to silence a bogus warning.
2009-05-02 16:16:28 +03:00
Lasse Collin 02ddf09bc3 Put the interesting parts of XZ Utils into the public domain.
Some minor documentation cleanups were made at the same time.
2009-04-13 11:27:40 +03:00
Lasse Collin 3b34851de1 Sort of garbage collection commit. :-| Many things are still
broken. API has changed a lot and it will still change a
little more here and there. The command line tool doesn't
have all the required changes to reflect the API changes, so
it's easy to get "internal error" or trigger assertions.
2008-08-28 22:53:15 +03:00
Lasse Collin 7d17818cec Update the code to mostly match the new simpler file format
specification. Simplify things by removing most of the
support for known uncompressed size in most places.
There are some miscellaneous changes here and there too.

The API of liblzma has got many changes and still some
more will be done soon. While most of the code has been
updated, some things are not fixed (the command line tool
will choke with invalid filter chain, if nothing else).

Subblock filter is somewhat broken for now. It will be
updated once the encoded format of the Subblock filter
has been decided.
2008-06-18 18:02:10 +03:00
Lasse Collin 5d018dc035 Imported to git. 2007-12-09 00:42:33 +02:00