memory copy optimization

src/mining.nim

@@ -43,7 +43,6 @@ proc mulCarry(a, b: uint64): tuple[carry, unit: uint64] =
 
   # Case 1: z0 = a_lo * b_lo
   # It cannot overflow
-  # We only need the hi part of z0, to add to the lo part of z1
     z0 = a_lo * b_lo
 
   # Case 2: z1 = a_lo * b_hi + a_hi * b_lo
@@ -89,7 +88,7 @@ proc isValid(nonce: uint64,
 
   # First we convert the Hash[256] to an array of 4 uint64 and then
   # only consider the most significant
-  let hash_qwords = cast[array[4, uint64]](candidate_hash.value)
+  let hash_qwords = cast[ptr array[4, uint64]](candidate_hash.value.unsafeAddr)
   var
     unit = 0'u64
     carry = 0'u64

src/proof_of_work.nim

@@ -187,17 +187,16 @@ template hashimoto(header: Hash[256],
     mix = zipMap(mix, newdata, fnv(x, y))
 
   # compress mix
-  var cmix{.noInit.}: array[8, uint32]
+  # ⚠⚠ Warning ⚠⚠: Another bigEndian littleEndian issue?
+  # It doesn't seem like the uint32 in cmix need to be changed to big endian
+  # cmix is an alias to the result.mix_digest
+  let cmix = cast[ptr array[8, uint32]](addr result.mix_digest)
   for i in countup(0, mix.len - 1, 4):
     cmix[i div 4] = mix[i].fnv(mix[i+1]).fnv(mix[i+2]).fnv(mix[i+3])
 
-  # ⚠⚠ Warning ⚠⚠: Another bigEndian littleEndian issue?
-  # It doesn't seem like the uint32 in cmix need to be changed to big endian
-  result.mix_digest = cast[Hash[256]](cmix)
-
   var concat{.noInit.}: array[64 + 32, byte]
   concat[0..<64] = s_bytes[]
-  concat[64..<96] = cast[array[32, byte]](cmix)
+  concat[64..<96] = cast[array[32, byte]](result.mix_digest)
   result.value = keccak_256(concat)
 
 proc hashimoto_light*(full_size:Natural, cache: seq[Hash[512]],