Hide tempHash from the public API

src/randomx.cpp

@@ -363,21 +363,21 @@ extern "C" {
 		machine->getFinalResult(output, RANDOMX_HASH_SIZE);
 	}
 
-	void randomx_calculate_hash_first(randomx_vm* machine, uint64_t *tempHash, const void* input, size_t inputSize) {
-		blake2b(tempHash, sizeof(uint64_t) * 8, input, inputSize, nullptr, 0);
-		machine->initScratchpad(tempHash);
+	void randomx_calculate_hash_first(randomx_vm* machine, const void* input, size_t inputSize) {
+		blake2b(machine->tempHash, sizeof(machine->tempHash), input, inputSize, nullptr, 0);
+		machine->initScratchpad(machine->tempHash);
 	}
 
-	void randomx_calculate_hash_next(randomx_vm* machine, uint64_t *tempHash, const void* nextInput, size_t nextInputSize, void* output) {
+	void randomx_calculate_hash_next(randomx_vm* machine, const void* nextInput, size_t nextInputSize, void* output) {
 		machine->resetRoundingMode();
 		for (uint32_t chain = 0; chain < RANDOMX_PROGRAM_COUNT - 1; ++chain) {
-			machine->run(tempHash);
-			blake2b(tempHash, sizeof(uint64_t) * 8, machine->getRegisterFile(), sizeof(randomx::RegisterFile), nullptr, 0);
+			machine->run(machine->tempHash);
+			blake2b(machine->tempHash, sizeof(machine->tempHash), machine->getRegisterFile(), sizeof(randomx::RegisterFile), nullptr, 0);
 		}
-		machine->run(tempHash);
+		machine->run(machine->tempHash);
 
 		// Finish current hash and fill the scratchpad for the next hash at the same time
-		blake2b(tempHash, sizeof(uint64_t) * 8, nextInput, nextInputSize, nullptr, 0);
-		machine->hashAndFill(output, RANDOMX_HASH_SIZE, tempHash);
+		blake2b(machine->tempHash, sizeof(machine->tempHash), nextInput, nextInputSize, nullptr, 0);
+		machine->hashAndFill(output, RANDOMX_HASH_SIZE, machine->tempHash);
 	}
 }

src/randomx.h

@@ -240,10 +240,11 @@ RANDOMX_EXPORT void randomx_destroy_vm(randomx_vm *machine);
 RANDOMX_EXPORT void randomx_calculate_hash(randomx_vm *machine, const void *input, size_t inputSize, void *output);
 
 /**
- * Paired functions used to calculate multiple RandomX hashes during mining for example.
+ * Paired functions used to calculate multiple RandomX hashes more efficiently.
+ * randomx_calculate_hash_first is called for the first input value.
+ * randomx_calculate_hash_next will output the hash value of the previous input.
  *
  * @param machine is a pointer to a randomx_vm structure. Must not be NULL.
- * @param tempHash an array of 8 64-bit values used to store intermediate data between calls to randomx_calculate_hash_first and randomx_calculate_hash_next.
  * @param input is a pointer to memory to be hashed. Must not be NULL.
  * @param inputSize is the number of bytes to be hashed.
  * @param nextInput is a pointer to memory to be hashed for the next hash. Must not be NULL.
@@ -251,8 +252,8 @@ RANDOMX_EXPORT void randomx_calculate_hash(randomx_vm *machine, const void *inpu
  * @param output is a pointer to memory where the hash will be stored. Must not
  *        be NULL and at least RANDOMX_HASH_SIZE bytes must be available for writing.
 */
-RANDOMX_EXPORT void randomx_calculate_hash_first(randomx_vm* machine, uint64_t *tempHash, const void* input, size_t inputSize);
-RANDOMX_EXPORT void randomx_calculate_hash_next(randomx_vm* machine, uint64_t *tempHash, const void* nextInput, size_t nextInputSize, void* output);
+RANDOMX_EXPORT void randomx_calculate_hash_first(randomx_vm* machine, const void* input, size_t inputSize);
+RANDOMX_EXPORT void randomx_calculate_hash_next(randomx_vm* machine, const void* nextInput, size_t nextInputSize, void* output);
 
 #if defined(__cplusplus)
 }

src/tests/benchmark.cpp

@@ -122,15 +122,13 @@ void mine(randomx_vm* vm, std::atomic<uint32_t>& atomicNonce, AtomicHash& result
 	void* noncePtr = blockTemplate + 39;
 	auto nonce = atomicNonce.fetch_add(1);
 
-	uint64_t tempHash[8];
-
 	store32(noncePtr, nonce);
-	randomx_calculate_hash_first(vm, tempHash, blockTemplate, sizeof(blockTemplate));
+	randomx_calculate_hash_first(vm, blockTemplate, sizeof(blockTemplate));
 
 	while (nonce < noncesCount) {
 		nonce = atomicNonce.fetch_add(1);
 		store32(noncePtr, nonce);
-		randomx_calculate_hash_next(vm, tempHash, blockTemplate, sizeof(blockTemplate), &hash);
+		randomx_calculate_hash_next(vm, blockTemplate, sizeof(blockTemplate), &hash);
 		result.xorWith(hash);
 	}
 }

src/virtual_machine.hpp

@@ -68,6 +68,7 @@ protected:
 	uint64_t datasetOffset;
 public:
 	std::string cacheKey;
+	alignas(16) uint64_t tempHash[8]; //8 64-bit values used to store intermediate data
 };
 
 namespace randomx {