The portable implementation doesn't use the light parameter causing (#…

…1126)

inconsistent results. I desk checked against the ARM64 implementation
that does NOT used the +crypto extensions, meaning it is emulated in
software- That implementation is essentially the same as the portable
implementation, some minor differences in the pre-amble but correctly
uses the light flag.

Adapting that over allows us to sync past block 321280, which previously
emitted an "unexpected difficulty" error.

This code path was never excercised due to the '-maes' flag being forced
on via CMake. That was removed in this commit to make it specifiable by
the user.

17be0ed

src/crypto/cn_turtle_hash.c

@@ -1395,8 +1395,6 @@ static void (*const extra_hashes[4])(const void *, size_t, char *) = {
 extern int aesb_single_round(const uint8_t *in, uint8_t*out, const uint8_t *expandedKey);
 extern int aesb_pseudo_round(const uint8_t *in, uint8_t *out, const uint8_t *expandedKey);
 
-static size_t e2i(const uint8_t* a, size_t count) { return (*((uint64_t*)a) / AES_BLOCK_SIZE) & (count - 1); }
-
 static void mul(const uint8_t* a, const uint8_t* b, uint8_t* res) {
   uint64_t a0, b0;
   uint64_t hi, lo;
@@ -1466,7 +1464,8 @@ void cn_turtle_hash(const void *data, size_t length, char *hash, int light, int
 {
   uint32_t init_rounds = (scratchpad / INIT_SIZE_BYTE);
   uint32_t aes_rounds = (iterations / 2);
-  size_t aes_init = (CN_TURTLE_PAGE_SIZE / AES_BLOCK_SIZE);
+  size_t TOTALBLOCKS = (CN_TURTLE_PAGE_SIZE / AES_BLOCK_SIZE);
+  size_t lightFlag = (light ? 2: 1);
 
 #ifndef FORCE_USE_HEAP
   uint8_t long_state[CN_TURTLE_PAGE_SIZE];
@@ -1517,16 +1516,18 @@ void cn_turtle_hash(const void *data, size_t length, char *hash, int light, int
      * next address  <-+
      */
     /* Iteration 1 */
-    j = e2i(a, aes_init);
+    #define state_index(x,div) (((*((uint64_t *)x) >> 4) & (TOTALBLOCKS /(div) - 1)) << 4)
+    j = state_index(a, lightFlag);
     copy_block(c1, &long_state[j]);
     aesb_single_round(c1, c1, a);
+
     VARIANT2_PORTABLE_SHUFFLE_ADD(long_state, j);
     copy_block(&long_state[j], c1);
     xor_blocks(&long_state[j], b);
-    assert(j == e2i(a, aes_init));
     VARIANT1_1(&long_state[j]);
+
     /* Iteration 2 */
-    j = e2i(c1, aes_init);
+    j = state_index(c1, lightFlag);
     copy_block(c2, &long_state[j]);
     VARIANT2_PORTABLE_INTEGER_MATH(c2, c1);
     mul(c1, c2, d);
@@ -1538,7 +1539,7 @@ void cn_turtle_hash(const void *data, size_t length, char *hash, int light, int
     xor_blocks(c1, c2);
     VARIANT1_2(c2 + 8);
     copy_block(&long_state[j], c2);
-    assert(j == e2i(a, aes_init));
+
     if (variant == 2) {
       copy_block(b + AES_BLOCK_SIZE, b);
     }