Commit 895be157 authored by Nicolas Kaiser's avatar Nicolas Kaiser Committed by Herbert Xu
Browse files

crypto: cast5 - simplify if-statements 



I noticed that by factoring out common rounds from the
branches of the if-statements in the encryption and
decryption functions, the executable file size goes down
significantly, for crypto/cast5.ko from 26688 bytes
to 24336 bytes (amd64).

On my test system, I saw a slight speedup. This is the
first time I'm doing such a benchmark - I found a similar
one on the crypto mailing list, and I hope I did it right?

Before:
# cryptsetup create dm-test /dev/hda2 -c cast5-cbc-plain -s 128
Passsatz eingeben: 
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,43484 s, 21,5 MB/s
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,4089 s, 21,8 MB/s
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,41091 s, 21,7 MB/s

After:
# cryptsetup create dm-test /dev/hda2 -c cast5-cbc-plain -s 128
Passsatz eingeben: 
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,38128 s, 22,0 MB/s
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,29486 s, 22,8 MB/s
# dd if=/dev/zero of=/dev/mapper/dm-test bs=1M count=50
52428800 Bytes (52 MB) kopiert, 2,37162 s, 22,1 MB/s

Signed-off-by: default avatarNicolas Kaiser <nikai@nikai.net>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 90246e79

crypto/cast5.c

+24 −50
Original line number Diff line number Diff line
@@ -604,7 +604,6 @@ static void cast5_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 
	 * Rounds 3, 6, 9, 12, and 15 use f function Type 3.

	 */



	if (!(c->rr)) {

	t = l; l = r; r = t ^ F1(r, Km[0], Kr[0]);

	t = l; l = r; r = t ^ F2(r, Km[1], Kr[1]);

	t = l; l = r; r = t ^ F3(r, Km[2], Kr[2]);
@@ -617,23 +616,11 @@ static void cast5_encrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 
	t = l; l = r; r = t ^ F1(r, Km[9], Kr[9]);

	t = l; l = r; r = t ^ F2(r, Km[10], Kr[10]);

	t = l; l = r; r = t ^ F3(r, Km[11], Kr[11]);

	if (!(c->rr)) {

		t = l; l = r; r = t ^ F1(r, Km[12], Kr[12]);

		t = l; l = r; r = t ^ F2(r, Km[13], Kr[13]);

		t = l; l = r; r = t ^ F3(r, Km[14], Kr[14]);

		t = l; l = r; r = t ^ F1(r, Km[15], Kr[15]);

	} else {

		t = l; l = r; r = t ^ F1(r, Km[0], Kr[0]);

		t = l; l = r; r = t ^ F2(r, Km[1], Kr[1]);

		t = l; l = r; r = t ^ F3(r, Km[2], Kr[2]);

		t = l; l = r; r = t ^ F1(r, Km[3], Kr[3]);

		t = l; l = r; r = t ^ F2(r, Km[4], Kr[4]);

		t = l; l = r; r = t ^ F3(r, Km[5], Kr[5]);

		t = l; l = r; r = t ^ F1(r, Km[6], Kr[6]);

		t = l; l = r; r = t ^ F2(r, Km[7], Kr[7]);

		t = l; l = r; r = t ^ F3(r, Km[8], Kr[8]);

		t = l; l = r; r = t ^ F1(r, Km[9], Kr[9]);

		t = l; l = r; r = t ^ F2(r, Km[10], Kr[10]);

		t = l; l = r; r = t ^ F3(r, Km[11], Kr[11]);

	}



	/* c1...c64 <-- (R16,L16).  (Exchange final blocks L16, R16 and
@@ -663,6 +650,7 @@ static void cast5_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 
		t = l; l = r; r = t ^ F3(r, Km[14], Kr[14]);

		t = l; l = r; r = t ^ F2(r, Km[13], Kr[13]);

		t = l; l = r; r = t ^ F1(r, Km[12], Kr[12]);

	}

	t = l; l = r; r = t ^ F3(r, Km[11], Kr[11]);

	t = l; l = r; r = t ^ F2(r, Km[10], Kr[10]);

	t = l; l = r; r = t ^ F1(r, Km[9], Kr[9]);
@@ -675,20 +663,6 @@ static void cast5_decrypt(struct crypto_tfm *tfm, u8 *outbuf, const u8 *inbuf) 
	t = l; l = r; r = t ^ F3(r, Km[2], Kr[2]);

	t = l; l = r; r = t ^ F2(r, Km[1], Kr[1]);

	t = l; l = r; r = t ^ F1(r, Km[0], Kr[0]);

	} else {

		t = l; l = r; r = t ^ F3(r, Km[11], Kr[11]);

		t = l; l = r; r = t ^ F2(r, Km[10], Kr[10]);

		t = l; l = r; r = t ^ F1(r, Km[9], Kr[9]);

		t = l; l = r; r = t ^ F3(r, Km[8], Kr[8]);

		t = l; l = r; r = t ^ F2(r, Km[7], Kr[7]);

		t = l; l = r; r = t ^ F1(r, Km[6], Kr[6]);

		t = l; l = r; r = t ^ F3(r, Km[5], Kr[5]);

		t = l; l = r; r = t ^ F2(r, Km[4], Kr[4]);

		t = l; l = r; r = t ^ F1(r, Km[3], Kr[3]);

		t = l; l = r; r = t ^ F3(r, Km[2], Kr[2]);

		t = l; l = r; r = t ^ F2(r, Km[1], Kr[1]);

		t = l; l = r; r = t ^ F1(r, Km[0], Kr[0]);

	}



	dst[0] = cpu_to_be32(r);

	dst[1] = cpu_to_be32(l);

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