Commit c7d0d0ae authored by Andy Polyakov's avatar Andy Polyakov
Browse files

xts128.c: minor optimizaton.

parent c9adde06

crypto/modes/xts128.c

+14 −12
Original line number Diff line number Diff line
@@ -107,14 +107,15 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, const unsigned char iv[16], 
			tweak.u[1] = (tweak.u[1]<<1)|carry;

		}

		else {

			unsigned int carry,c;

			size_t c;



			for (carry=0,i=0;i<16;++i) {

				c = tweak.c[i];

				tweak.c[i] = (c<<1)|carry;

				carry = c>>7;

			for (c=0,i=0;i<16;++i) {

				/*+ substitutes for |, because c is 1 bit */ 

				c += ((size_t)tweak.c[i])<<1;

				tweak.c[i] = (u8)c;

				c = c>>8;

			}

			tweak.c[0] ^= 0x87&(0-carry);

			tweak.c[0] ^= (u8)(0x87&(0-c));

		}

	}

	if (enc) {
@@ -142,14 +143,15 @@ int CRYPTO_xts128_encrypt(const XTS128_CONTEXT *ctx, const unsigned char iv[16], 
			tweak1.u[1] = (tweak.u[1]<<1)|carry;

		}

		else {

			unsigned int carry,c;

			size_t c;



			for (carry=0,i=0;i<16;++i) {

				c = tweak.c[i];

				tweak1.c[i] = (c<<1)|carry;

				carry = c>>7;

			for (c=0,i=0;i<16;++i) {

				/*+ substitutes for |, because c is 1 bit */ 

				c += ((size_t)tweak.c[i])<<1;

				tweak1.c[i] = (u8)c;

				c = c>>8;

			}

			tweak1.c[0] ^= 0x87&(0-carry);

			tweak1.c[0] ^= (u8)(0x87&(0-c));

		}

#if defined(STRICT_ALIGNMENT)

		memcpy(scratch.c,inp,16);