crypto, pow: add pure Go implementation of ethash

crypto/sha3/hashes.go

@@ -15,6 +15,9 @@ import (
 // NewKeccak256 creates a new Keccak-256 hash.
 func NewKeccak256() hash.Hash { return &state{rate: 136, outputLen: 32, dsbyte: 0x01} }
 
+// NewKeccak512 creates a new Keccak-512 hash.
+func NewKeccak512() hash.Hash { return &state{rate: 72, outputLen: 64, dsbyte: 0x01} }
+
 // New224 creates a new SHA3-224 hash.
 // Its generic security strength is 224 bits against preimage attacks,
 // and 112 bits against collision attacks.

crypto/sha3/keccakf_amd64.s

@@ -322,7 +322,6 @@
 // func keccakF1600(state *[25]uint64)
 TEXT ·keccakF1600(SB), 0, $200-8
 	MOVQ state+0(FP), rpState
-	SUBQ $(8*25), SP
 
 	// Convert the user state into an internal state
 	NOTQ _be(rpState)
@@ -388,5 +387,4 @@ TEXT ·keccakF1600(SB), 0, $200-8
 	NOTQ _mi(rpState)
 	NOTQ _sa(rpState)
 
-	ADDQ $(8*25), SP
 	RET