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Remove ttmath dependency for mining

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This commit is contained in:
mratsim 2018-02-27 19:31:25 +01:00
parent 0e1a1169e4
commit 4d1cc3a359
2 changed files with 12 additions and 19 deletions
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5
ethash.nimble
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@ -7,7 +7,7 @@ srcDir = "src"
### Dependencies
requires "nim >= 0.17.2", "keccak_tiny >= 0.1.0", "ttmath > 0.2.0" # ttmath with exposed table field is required for mining only
requires "nim >= 0.17.2", "keccak_tiny >= 0.1.0"
proc test(name: string, lang: string = "c") =
if not dirExists "build":
@ -25,5 +25,4 @@ task test, "Run Proof-of-Work tests (without mining)":
task test_mining, "Run Proof-of-Work and mining tests (test in release mode)":
switch("define", "release")
switch("define", "ethash_mining")
test "all_tests", "cpp"
test "all_tests"

26
src/mining.nim
View File

@ -2,15 +2,7 @@
# Distributed under the Apache v2 License (license terms are at http://www.apache.org/licenses/LICENSE-2.0).
import ./proof_of_work, ./private/casting
import ttmath, random, math
# TODO we don't really need ttmath here
proc readUint256BE*(ba: ByteArrayBE[32]): UInt256 {.noSideEffect.}=
## Convert a big-endian array of Bytes to an UInt256 (in native host endianness)
const N = 32
for i in 0 ..< N:
result = result shl 8 or ba[i].u256
import endians, random, math
proc willMulOverflow(a, b: uint64): bool {.noSideEffect.}=
# Returns true if a * b overflows
@ -77,9 +69,7 @@ proc isValid(nonce: uint64,
# i.e we only need to test that hashimoto * difficulty doesn't overflow uint256
# First run the hashimoto with the candidate nonce
let candidate = readUint256BE(cast[ByteArrayBE[32]](
hashimoto_full(full_size, dataset, header, nonce).value
))
let candidate_hash = hashimoto_full(full_size, dataset, header, nonce)
# Now check if the multiplication of both would overflow
@ -91,14 +81,18 @@ proc isValid(nonce: uint64,
#
# Overflow occurs only if "1 * 5" overflows 2^64
# 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)
var hi_hash: uint64
when system.cpuEndian == littleEndian:
let hi_hash = candidate.table[3]
littleEndian64(hi_hash.addr, hash_qwords[3].unsafeAddr)
else:
let hi_hash = candidate.table[0]
littleEndian64(hi_hash.addr, hash_qwords[0].unsafeAddr)
result = not willMulOverflow(hi_hash, difficulty)
proc mine*(full_size: Natural, dataset: seq[Hash[512]], header: Hash[256], difficulty: uint64): uint64 =
# Returns a valid nonce
@ -107,4 +101,4 @@ proc mine*(full_size: Natural, dataset: seq[Hash[512]], header: Hash[256], diffi
# Also random is deprecate and do not include the end of the range.
while not result.isValid(difficulty, full_size, dataset, header):
inc(result) # we rely on uin overflow (mod 2^64) here.
inc(result) # we rely on uin overflow (mod 2^64) here.