AVR inline assembly version of Speck

doc/crypto.dox

@@ -47,6 +47,11 @@ constant-time, and much more secure.  AES128, AES192, and AES256 are
 provided for use in applications where compatibility with other systems
 is desirable.
 
+If code size is an issue for your application (for example on very low end
+Arduino variants), then Speck on AVR is less than half the code size of
+ChaCha, at the cost of more data memory for the state and longer key
+setup times.
+
 BLAKE2s and BLAKE2b are variations on the ChaCha stream cipher, designed for
 hashing, with 256-bit and 512-bit hash outputs respectively.  They are
 intended as high performance replacements for SHA256 and SHA512 for when
@@ -71,9 +76,9 @@ Ardunino Mega 2560 running at 16 MHz are similar:
 <tr><td>ChaCha (20 rounds)</td><td align="right">14.87us</td><td align="right">14.88us</td><td align="right">43.74us</td><td align="right">132</td></tr>
 <tr><td>ChaCha (12 rounds)</td><td align="right">10.38us</td><td align="right">10.38us</td><td align="right">43.74us</td><td align="right">132</td></tr>
 <tr><td>ChaCha (8 rounds)</td><td align="right">8.13us</td><td align="right">8.14us</td><td align="right">43.74us</td><td align="right">132</td></tr>
-<tr><td>Speck (128-bit key)</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">275</td></tr>
+<tr><td>Speck (128-bit key, ECB mode)</td><td align="right">10.72us</td><td align="right">11.09us</td><td align="right">304.56us</td><td align="right">275</td></tr>
-<tr><td>Speck (192-bit key)</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">275</td></tr>
+<tr><td>Speck (192-bit key, ECB mode)</td><td align="right">11.03us</td><td align="right">11.42us</td><td align="right">316.32us</td><td align="right">275</td></tr>
-<tr><td>Speck (256-bit key)</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">N.NNus</td><td align="right">275</td></tr>
+<tr><td>Speck (256-bit key, ECB mode)</td><td align="right">11.35us</td><td align="right">11.74us</td><td align="right">328.33us</td><td align="right">275</td></tr>
 <tr><td colspan="5"> </td></tr>
 <tr><td>AEAD Algorithm</td><td align="right">Encryption (per byte)</td><td align="right">Decryption (per byte)</td><td>Key Setup</td><td>State Size (bytes)</td></tr>
 <tr><td>ChaChaPoly</td><td align="right">41.23us</td><td align="right">41.23us</td><td align="right">902.55us</td><td align="right">255</td></tr>
@@ -122,6 +127,9 @@ All figures are for the Arduino Due running at 84 MHz:
 <tr><td>ChaCha (20 rounds)</td><td align="right">0.87us</td><td align="right">0.88us</td><td align="right">4.96us</td><td align="right">136</td></tr>
 <tr><td>ChaCha (12 rounds)</td><td align="right">0.70us</td><td align="right">0.71us</td><td align="right">4.96us</td><td align="right">136</td></tr>
 <tr><td>ChaCha (8 rounds)</td><td align="right">0.62us</td><td align="right">0.62us</td><td align="right">4.96us</td><td align="right">136</td></tr>
+<tr><td>Speck (128-bit key, ECB mode)</td><td align="right">0.88us</td><td align="right">1.17us</td><td align="right">37.54us</td><td align="right">288</td></tr>
+<tr><td>Speck (192-bit key, ECB mode)</td><td align="right">0.90us</td><td align="right">1.20us</td><td align="right">38.92us</td><td align="right">288</td></tr>
+<tr><td>Speck (256-bit key, ECB mode)</td><td align="right">0.93us</td><td align="right">1.23us</td><td align="right">40.10us</td><td align="right">288</td></tr>
 <tr><td colspan="5"> </td></tr>
 <tr><td>AEAD Algorithm</td><td align="right">Encryption (per byte)</td><td align="right">Decryption (per byte)</td><td>Key Setup</td><td>State Size (bytes)</td></tr>
 <tr><td>ChaChaPoly</td><td align="right">1.66us</td><td align="right">1.66us</td><td align="right">45.02us</td><td align="right">280</td></tr>

libraries/Crypto/Speck.cpp

@@ -37,7 +37,7 @@
  * This class implements the Speck family that uses 128-bit block sizes
  * with 128-bit, 192-bit, or 256-bit key sizes.  Other Speck families support
  * smaller block sizes of 32, 48, 64, or 96 bits but such block sizes are
- * really too small for use in modern cryptosystems.
+ * too small for use in modern cryptosystems.
  *
  * \note Current crytoanalysis (up until 2015) has not revealed any obvious
  * weaknesses in the full-round version of Speck.  But if you are wary of
@@ -47,6 +47,16 @@
  * http://eprint.iacr.org/2013/404
  */
 
+// The "avr-gcc" compiler doesn't do a very good job of compiling
+// code involving 64-bit values.  So we have to use inline assembly.
+// It also helps to break the state up into 32-bit quantities
+// because "asm" supports register names like %A0, %B0, %C0, %D0
+// for the bytes in a 32-bit quantity, but it does not support
+// %E0, %F0, %G0, %H0 for the high bytes of a 64-bit quantity.
+#if defined(__AVR__)
+#define USE_AVR_INLINE_ASM 1
+#endif
+
 /**
  * \brief Constructs a Speck block cipher with no initial key.
  *
@@ -74,33 +84,7 @@ size_t Speck::keySize() const
     return 32;
 }
 
-// Pack/unpack big-endian 64-bit quantities.
+// Pack/unpack byte-aligned big-endian 64-bit quantities.
-#if defined(__AVR__)
-#define pack64(data, value) \
-    do { \
-        const uint8_t *src = (const uint8_t *)&(value); \
-        (data)[0] = src[7]; \
-        (data)[1] = src[6]; \
-        (data)[2] = src[5]; \
-        (data)[3] = src[4]; \
-        (data)[4] = src[3]; \
-        (data)[5] = src[2]; \
-        (data)[6] = src[1]; \
-        (data)[7] = src[0]; \
-    } while (0)
-#define unpack64(value, data) \
-    do { \
-        uint8_t *dest = (uint8_t *)&(value); \
-        dest[0] = (data)[7]; \
-        dest[1] = (data)[6]; \
-        dest[2] = (data)[5]; \
-        dest[3] = (data)[4]; \
-        dest[4] = (data)[3]; \
-        dest[5] = (data)[2]; \
-        dest[6] = (data)[1]; \
-        dest[7] = (data)[0]; \
-    } while (0)
-#else
 #define pack64(data, value) \
     do { \
         uint64_t v = htobe64((value)); \
@@ -111,10 +95,182 @@ size_t Speck::keySize() const
         memcpy(&(value), (data), sizeof(uint64_t)); \
         (value) = be64toh((value)); \
     } while (0)
-#endif
 
 bool Speck::setKey(const uint8_t *key, size_t len)
 {
+#if USE_AVR_INLINE_ASM
+    uint64_t l[4];
+    uint8_t m, mb;
+    if (len == 32) {
+        m = 4;
+        mb = 3 * 8;
+    } else if (len == 24) {
+        m = 3;
+        mb = 2 * 8;
+    } else if (len == 16) {
+        m = 2;
+        mb = 8;
+    } else {
+        return false;
+    }
+    rounds = 30 + m;
+
+    // Copy the first (m - 1) * 8 bytes of the key into the "l" array
+    // in reverse order to convert big endian into little-endian.
+    __asm__ __volatile__ (
+        "1:\n"
+        "ld __tmp_reg__,-Z\n"
+        "st X+,__tmp_reg__\n"
+        "dec %2\n"
+        "brne 1b\n"
+        : : "x"(l), "z"(key + len - 8), "r"(mb)
+    );
+
+    // Copy the final 8 bytes of the key into k[0] in reverse order.
+    __asm__ __volatile__ (
+        "1:\n"
+        "ld __tmp_reg__,-Z\n"
+        "st X+,__tmp_reg__\n"
+        "dec %2\n"
+        "brne 1b\n"
+        : : "x"(k), "z"(key + len), "r"(8)
+    );
+
+    // Expand the key to the full key schedule.
+    __asm__ __volatile__ (
+        "1:\n"
+        // l[li_out] = (k[i] + rightRotate8_64(l[li_in])) ^ i;
+        "add %A1,%2\n"              // X = &(l[li_in])
+        "adc %B1,__zero_reg__\n"
+        "ld r8,X+\n"                // x = l[li_in]
+        "ld r9,X+\n"
+        "ld r10,X+\n"
+        "ld r11,X+\n"
+        "ld r12,X+\n"
+        "ld r13,X+\n"
+        "ld r14,X+\n"
+        "ld r15,X+\n"
+
+        "mov __tmp_reg__,r8\n"      // x = rightRotate8_64(l[li_in])
+        "mov r8,r9\n"
+        "mov r9,r10\n"
+        "mov r10,r11\n"
+        "mov r11,r12\n"
+        "mov r12,r13\n"
+        "mov r13,r14\n"
+        "mov r14,r15\n"
+        "mov r15,__tmp_reg__\n"
+
+        "ld r16,Z+\n"               // y = k[i]
+        "ld r17,Z+\n" 
+        "ld r18,Z+\n" 
+        "ld r19,Z+\n" 
+        "ld r20,Z+\n" 
+        "ld r21,Z+\n" 
+        "ld r22,Z+\n" 
+        "ld r23,Z+\n" 
+
+        "add r8,r16\n"              // x += y
+        "adc r9,r17\n"
+        "adc r10,r18\n"
+        "adc r11,r19\n"
+        "adc r12,r20\n"
+        "adc r13,r21\n"
+        "adc r14,r22\n"
+        "adc r15,r23\n"
+
+        "eor r8,%4\n"               // x ^= i
+
+        // X = X - li_in + li_out
+        "ldi r24,8\n"               // li_in = li_in + 1
+        "add %2,r24\n"
+        "sub %A1,%2\n"              // return X to its initial value
+        "sbc %B1,__zero_reg__\n"
+        "ldi r25,0x1f\n"
+        "and %2,r25\n"              // li_in = li_in % 4
+        "add %A1,%3\n"              // X = &(l[li_out])
+        "adc %B1,__zero_reg__\n"
+
+        "st X+,r8\n"                // l[li_out] = x
+        "st X+,r9\n"
+        "st X+,r10\n"
+        "st X+,r11\n"
+        "st X+,r12\n"
+        "st X+,r13\n"
+        "st X+,r14\n"
+        "st X+,r15\n"
+
+        "add %3,r24\n"              // li_out = li_out + 1
+        "sub %A1,%3\n"              // return X to its initial value
+        "sbc %B1,__zero_reg__\n"
+        "and %3,r25\n"              // li_out = li_out % 4
+
+        // k[i + 1] = leftRotate3_64(k[i]) ^ l[li_out];
+        "lsl r16\n"                 // y = leftRotate1_64(y)
+        "rol r17\n"
+        "rol r18\n"
+        "rol r19\n"
+        "rol r20\n"
+        "rol r21\n"
+        "rol r22\n"
+        "rol r23\n"
+        "adc r16,__zero_reg__\n"
+
+        "lsl r16\n"                 // y = leftRotate1_64(y)
+        "rol r17\n"
+        "rol r18\n"
+        "rol r19\n"
+        "rol r20\n"
+        "rol r21\n"
+        "rol r22\n"
+        "rol r23\n"
+        "adc r16,__zero_reg__\n"
+
+        "lsl r16\n"                 // y = leftRotate1_64(y)
+        "rol r17\n"
+        "rol r18\n"
+        "rol r19\n"
+        "rol r20\n"
+        "rol r21\n"
+        "rol r22\n"
+        "rol r23\n"
+        "adc r16,__zero_reg__\n"
+
+        "eor r16,r8\n"              // y ^= x
+        "eor r17,r9\n"
+        "eor r18,r10\n"
+        "eor r19,r11\n"
+        "eor r20,r12\n"
+        "eor r21,r13\n"
+        "eor r22,r14\n"
+        "eor r23,r15\n"
+
+        "st Z,r16\n"                // k[i + 1] = y
+        "std Z+1,r17\n"
+        "std Z+2,r18\n"
+        "std Z+3,r19\n"
+        "std Z+4,r20\n"
+        "std Z+5,r21\n"
+        "std Z+6,r22\n"
+        "std Z+7,r23\n"
+
+        // Loop
+        "inc %4\n"                  // ++i
+        "dec %5\n"                  // --rounds
+        "breq 2f\n"
+        "rjmp 1b\n"
+        "2:\n"
+
+        : : "z"(k), "x"(l),
+            "r"((uint8_t)0),                // initial value of li_in
+            "r"((uint8_t)((m - 1) * 8)),    // initial value of li_out
+            "r"(0),                         // initial value of i
+            "r"(rounds - 1)
+        :  "r8",  "r9", "r10", "r11", "r12", "r13", "r14", "r15",
+          "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
+          "r24", "r25"
+    );
+#else
     uint64_t l[4];
     uint8_t m;
     if (len == 32) {
@@ -146,12 +302,149 @@ bool Speck::setKey(const uint8_t *key, size_t len)
         if ((++li_out) >= m)
             li_out = 0;
     }
+#endif
     clean(l);
     return true;
 }
 
 void Speck::encryptBlock(uint8_t *output, const uint8_t *input)
 {
+#if USE_AVR_INLINE_ASM
+    uint32_t xlow, xhigh, ylow, yhigh;
+
+    // Unpack the input into the x and y variables, converting
+    // from big-endian into little-endian in the process.
+    __asm__ __volatile__ (
+        "ld %D1,Z\n"
+        "ldd %C1,Z+1\n"
+        "ldd %B1,Z+2\n"
+        "ldd %A1,Z+3\n"
+        "ldd %D0,Z+4\n"
+        "ldd %C0,Z+5\n"
+        "ldd %B0,Z+6\n"
+        "ldd %A0,Z+7\n"
+        "ldd %D3,Z+8\n"
+        "ldd %C3,Z+9\n"
+        "ldd %B3,Z+10\n"
+        "ldd %A3,Z+11\n"
+        "ldd %D2,Z+12\n"
+        "ldd %C2,Z+13\n"
+        "ldd %B2,Z+14\n"
+        "ldd %A2,Z+15\n"
+        : "=r"(xlow), "=r"(xhigh), "=r"(ylow), "=r"(yhigh)
+        : "z"(input)
+    );
+
+    // Perform all encryption rounds.  Z points to the key schedule.
+    __asm__ __volatile__ (
+        "1:\n"
+        // x = (rightRotate8_64(x) + y) ^ *s++;
+        "mov __tmp_reg__,%A0\n"     // x = rightRotate8_64(x)
+        "mov %A0,%B0\n"
+        "mov %B0,%C0\n"
+        "mov %C0,%D0\n"
+        "mov %D0,%A1\n"
+        "mov %A1,%B1\n"
+        "mov %B1,%C1\n"
+        "mov %C1,%D1\n"
+        "mov %D1,__tmp_reg__\n"
+
+        "add %A0,%A2\n"             // x += y
+        "adc %B0,%B2\n"
+        "adc %C0,%C2\n"
+        "adc %D0,%D2\n"
+        "adc %A1,%A3\n"
+        "adc %B1,%B3\n"
+        "adc %C1,%C3\n"
+        "adc %D1,%D3\n"
+
+        "ld __tmp_reg__,Z+\n"       // x ^= *s++
+        "eor %A0,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %B0,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %C0,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %D0,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %A1,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %B1,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %C1,__tmp_reg__\n"
+        "ld __tmp_reg__,Z+\n"
+        "eor %D1,__tmp_reg__\n"
+
+        // y = leftRotate3_64(y) ^ x;
+        "lsl %A2\n"                 // y = leftRotate1_64(y)
+        "rol %B2\n"
+        "rol %C2\n"
+        "rol %D2\n"
+        "rol %A3\n"
+        "rol %B3\n"
+        "rol %C3\n"
+        "rol %D3\n"
+        "adc %A2,__zero_reg__\n"
+
+        "lsl %A2\n"                 // y = leftRotate1_64(y)
+        "rol %B2\n"
+        "rol %C2\n"
+        "rol %D2\n"
+        "rol %A3\n"
+        "rol %B3\n"
+        "rol %C3\n"
+        "rol %D3\n"
+
+        "adc %A2,__zero_reg__\n"
+        "lsl %A2\n"                 // y = leftRotate1_64(y)
+        "rol %B2\n"
+        "rol %C2\n"
+        "rol %D2\n"
+        "rol %A3\n"
+        "rol %B3\n"
+        "rol %C3\n"
+        "rol %D3\n"
+        "adc %A2,__zero_reg__\n"
+
+        "eor %A2,%A0\n"             // y ^= x
+        "eor %B2,%B0\n"
+        "eor %C2,%C0\n"
+        "eor %D2,%D0\n"
+        "eor %A3,%A1\n"
+        "eor %B3,%B1\n"
+        "eor %C3,%C1\n"
+        "eor %D3,%D1\n"
+
+        // Loop
+        "dec %5\n"                  // --round
+        "breq 2f\n"
+        "rjmp 1b\n"
+        "2:\n"
+        : "+r"(xlow), "+r"(xhigh), "+r"(ylow), "+r"(yhigh)
+        : "z"(k), "r"(rounds)
+    );
+
+    // Pack the results into the output and convert back to big-endian.
+    __asm__ __volatile__ (
+        "st Z,%D1\n"
+        "std Z+1,%C1\n"
+        "std Z+2,%B1\n"
+        "std Z+3,%A1\n"
+        "std Z+4,%D0\n"
+        "std Z+5,%C0\n"
+        "std Z+6,%B0\n"
+        "std Z+7,%A0\n"
+        "std Z+8,%D3\n"
+        "std Z+9,%C3\n"
+        "std Z+10,%B3\n"
+        "std Z+11,%A3\n"
+        "std Z+12,%D2\n"
+        "std Z+13,%C2\n"
+        "std Z+14,%B2\n"
+        "std Z+15,%A2\n"
+        : : "r"(xlow), "r"(xhigh), "r"(ylow), "r"(yhigh), "z"(output)
+    );
+#else
     uint64_t x, y;
     const uint64_t *s = k;
     unpack64(x, input);
@@ -162,10 +455,150 @@ void Speck::encryptBlock(uint8_t *output, const uint8_t *input)
     }
     pack64(output, x);
     pack64(output + 8, y);
+#endif
 }
 
 void Speck::decryptBlock(uint8_t *output, const uint8_t *input)
 {
+#if USE_AVR_INLINE_ASM
+    uint32_t xlow, xhigh, ylow, yhigh;
+
+    // Unpack the input into the x and y variables, converting
+    // from big-endian into little-endian in the process.
+    __asm__ __volatile__ (
+        "ld %D1,Z\n"
+        "ldd %C1,Z+1\n"
+        "ldd %B1,Z+2\n"
+        "ldd %A1,Z+3\n"
+        "ldd %D0,Z+4\n"
+        "ldd %C0,Z+5\n"
+        "ldd %B0,Z+6\n"
+        "ldd %A0,Z+7\n"
+        "ldd %D3,Z+8\n"
+        "ldd %C3,Z+9\n"
+        "ldd %B3,Z+10\n"
+        "ldd %A3,Z+11\n"
+        "ldd %D2,Z+12\n"
+        "ldd %C2,Z+13\n"
+        "ldd %B2,Z+14\n"
+        "ldd %A2,Z+15\n"
+        : "=r"(xlow), "=r"(xhigh), "=r"(ylow), "=r"(yhigh)
+        : "z"(input)
+    );
+
+    // Perform all decryption rounds.  Z points to the end of key schedule.
+    __asm__ __volatile__ (
+        "1:\n"
+        // y = rightRotate3_64(x ^ y);
+        "eor %A2,%A0\n"             // y ^= x
+        "eor %B2,%B0\n"
+        "eor %C2,%C0\n"
+        "eor %D2,%D0\n"
+        "eor %A3,%A1\n"
+        "eor %B3,%B1\n"
+        "eor %C3,%C1\n"
+        "eor %D3,%D1\n"
+
+        "bst %A2,0\n"               // y = rightRotate1_64(y)
+        "ror %D3\n"
+        "ror %C3\n"
+        "ror %B3\n"
+        "ror %A3\n"
+        "ror %D2\n"
+        "ror %C2\n"
+        "ror %B2\n"
+        "ror %A2\n"
+        "bld %D3,7\n"
+
+        "bst %A2,0\n"               // y = rightRotate1_64(y)
+        "ror %D3\n"
+        "ror %C3\n"
+        "ror %B3\n"
+        "ror %A3\n"
+        "ror %D2\n"
+        "ror %C2\n"
+        "ror %B2\n"
+        "ror %A2\n"
+        "bld %D3,7\n"
+
+        "bst %A2,0\n"               // y = rightRotate1_64(y)
+        "ror %D3\n"
+        "ror %C3\n"
+        "ror %B3\n"
+        "ror %A3\n"
+        "ror %D2\n"
+        "ror %C2\n"
+        "ror %B2\n"
+        "ror %A2\n"
+        "bld %D3,7\n"
+
+        // x = leftRotate8_64((x ^ *s--) - y);
+        "ld __tmp_reg__,-Z\n"       // x ^= *s--
+        "eor %D1,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %C1,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %B1,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %A1,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %D0,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %C0,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %B0,__tmp_reg__\n"
+        "ld __tmp_reg__,-Z\n"
+        "eor %A0,__tmp_reg__\n"
+
+        "sub %A0,%A2\n"             // x -= y
+        "sbc %B0,%B2\n"
+        "sbc %C0,%C2\n"
+        "sbc %D0,%D2\n"
+        "sbc %A1,%A3\n"
+        "sbc %B1,%B3\n"
+        "sbc %C1,%C3\n"
+        "sbc %D1,%D3\n"
+
+        "mov __tmp_reg__,%D1\n"     // x = lefRotate8_64(x)
+        "mov %D1,%C1\n"
+        "mov %C1,%B1\n"
+        "mov %B1,%A1\n"
+        "mov %A1,%D0\n"
+        "mov %D0,%C0\n"
+        "mov %C0,%B0\n"
+        "mov %B0,%A0\n"
+        "mov %A0,__tmp_reg__\n"
+
+        // Loop
+        "dec %5\n"                  // --round
+        "breq 2f\n"
+        "rjmp 1b\n"
+        "2:\n"
+        : "+r"(xlow), "+r"(xhigh), "+r"(ylow), "+r"(yhigh)
+        : "z"(k + rounds), "r"(rounds)
+    );
+
+    // Pack the results into the output and convert back to big-endian.
+    __asm__ __volatile__ (
+        "st Z,%D1\n"
+        "std Z+1,%C1\n"
+        "std Z+2,%B1\n"
+        "std Z+3,%A1\n"
+        "std Z+4,%D0\n"
+        "std Z+5,%C0\n"
+        "std Z+6,%B0\n"
+        "std Z+7,%A0\n"
+        "std Z+8,%D3\n"
+        "std Z+9,%C3\n"
+        "std Z+10,%B3\n"
+        "std Z+11,%A3\n"
+        "std Z+12,%D2\n"
+        "std Z+13,%C2\n"
+        "std Z+14,%B2\n"
+        "std Z+15,%A2\n"
+        : : "r"(xlow), "r"(xhigh), "r"(ylow), "r"(yhigh), "z"(output)
+    );
+#else
     uint64_t x, y;
     const uint64_t *s = k + rounds - 1;
     unpack64(x, input);
@@ -176,6 +609,7 @@ void Speck::decryptBlock(uint8_t *output, const uint8_t *input)
     }
     pack64(output, x);
     pack64(output + 8, y);
+#endif
 }
 
 void Speck::clear()