[CRYPTO] twofish: i586 assembly version

The patch passed the trycpt tests and automated filesystem tests.
This rewrite resulted in some nice perfomance increase over my last patch.

Short summary of the tcrypt benchmarks:

Twofish Assembler vs. Twofish C (256bit 8kb block CBC)
encrypt: -33% Cycles
decrypt: -45% Cycles

Twofish Assembler vs. AES Assembler (128bit 8kb block CBC)
encrypt: +3%  Cycles
decrypt: -22% Cycles

Twofish Assembler vs. AES Assembler (256bit 8kb block CBC)
encrypt: -20% Cycles
decrypt: -36% Cycles

Full Output:
http://homepages.tu-darmstadt.de/~fritschi/twofish/tcrypt-speed-twofish-asm-i586.txt
http://homepages.tu-darmstadt.de/~fritschi/twofish/tcrypt-speed-twofish-c-i586.txt
http://homepages.tu-darmstadt.de/~fritschi/twofish/tcrypt-speed-aes-asm-i586.txt


Here is another bonnie++ benchmark with encrypted filesystems. All runs with
the twofish assembler modules max out the drivespeed. It should give some
idea what the module can do for encrypted filesystem performance even though
you can't see the full numbers.

http://homepages.tu-darmstadt.de/~fritschi/twofish/output_20060611_205432_x86.html

Signed-off-by: Joachim Fritschi <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

crypto/Kconfig

@@ -150,6 +150,21 @@ config CRYPTO_TWOFISH_COMMON
 	  Common parts of the Twofish cipher algorithm shared by the
 	  generic c and the assembler implementations.
 
+config CRYPTO_TWOFISH_586
+	tristate "Twofish cipher algorithms (i586)"
+	depends on CRYPTO && ((X86 || UML_X86) && !64BIT)
+	select CRYPTO_TWOFISH_COMMON
+	help
+	  Twofish cipher algorithm.
+
+	  Twofish was submitted as an AES (Advanced Encryption Standard)
+	  candidate cipher by researchers at CounterPane Systems.  It is a
+	  16 round block cipher supporting key sizes of 128, 192, and 256
+	  bits.
+
+	  See also:
+	  <http://www.schneier.com/twofish.html>
+
 config CRYPTO_SERPENT
 	tristate "Serpent cipher algorithm"
 	depends on CRYPTO