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      1 // Copyright 2012 The Go Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style
      3 // license that can be found in the LICENSE file.
      4 
      5 // +build amd64
      6 
      7 package aes
      8 
      9 // defined in asm_$GOARCH.s
     10 func hasAsm() bool
     11 func encryptBlockAsm(nr int, xk *uint32, dst, src *byte)
     12 func decryptBlockAsm(nr int, xk *uint32, dst, src *byte)
     13 func expandKeyAsm(nr int, key *byte, enc *uint32, dec *uint32)
     14 
     15 var useAsm = hasAsm()
     16 
     17 func encryptBlock(xk []uint32, dst, src []byte) {
     18 	if useAsm {
     19 		encryptBlockAsm(len(xk)/4-1, &xk[0], &dst[0], &src[0])
     20 	} else {
     21 		encryptBlockGo(xk, dst, src)
     22 	}
     23 }
     24 
     25 func decryptBlock(xk []uint32, dst, src []byte) {
     26 	if useAsm {
     27 		decryptBlockAsm(len(xk)/4-1, &xk[0], &dst[0], &src[0])
     28 	} else {
     29 		decryptBlockGo(xk, dst, src)
     30 	}
     31 }
     32 
     33 func expandKey(key []byte, enc, dec []uint32) {
     34 	if useAsm {
     35 		rounds := 10
     36 		switch len(key) {
     37 		case 128 / 8:
     38 			rounds = 10
     39 		case 192 / 8:
     40 			rounds = 12
     41 		case 256 / 8:
     42 			rounds = 14
     43 		}
     44 		expandKeyAsm(rounds, &key[0], &enc[0], &dec[0])
     45 	} else {
     46 		expandKeyGo(key, enc, dec)
     47 	}
     48 }
     49