libgo/go/crypto/aes/cipher_amd64.go

   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 ignore
   6
   7 package aes
   8
   9 import (
  10         "crypto/cipher"
  11         "crypto/internal/cipherhw"
  12 )
  13
  14 // defined in asm_amd64.s
  15 func encryptBlockAsm(nr int, xk *uint32, dst, src *byte)
  16 func decryptBlockAsm(nr int, xk *uint32, dst, src *byte)
  17 func expandKeyAsm(nr int, key *byte, enc *uint32, dec *uint32)
  18
  19 type aesCipherAsm struct {
  20         aesCipher
  21 }
  22
  23 var useAsm = cipherhw.AESGCMSupport()
  24
  25 func newCipher(key []byte) (cipher.Block, error) {
  26         if !useAsm {
  27                 return newCipherGeneric(key)
  28         }
  29         n := len(key) + 28
  30         c := aesCipherAsm{aesCipher{make([]uint32, n), make([]uint32, n)}}
  31         rounds := 10
  32         switch len(key) {
  33         case 128 / 8:
  34                 rounds = 10
  35         case 192 / 8:
  36                 rounds = 12
  37         case 256 / 8:
  38                 rounds = 14
  39         }
  40         expandKeyAsm(rounds, &key[0], &c.enc[0], &c.dec[0])
  41         if hasGCMAsm() {
  42                 return &aesCipherGCM{c}, nil
  43         }
  44
  45         return &c, nil
  46 }
  47
  48 func (c *aesCipherAsm) BlockSize() int { return BlockSize }
  49
  50 func (c *aesCipherAsm) Encrypt(dst, src []byte) {
  51         if len(src) < BlockSize {
  52                 panic("crypto/aes: input not full block")
  53         }
  54         if len(dst) < BlockSize {
  55                 panic("crypto/aes: output not full block")
  56         }
  57         encryptBlockAsm(len(c.enc)/4-1, &c.enc[0], &dst[0], &src[0])
  58 }
  59
  60 func (c *aesCipherAsm) Decrypt(dst, src []byte) {
  61         if len(src) < BlockSize {
  62                 panic("crypto/aes: input not full block")
  63         }
  64         if len(dst) < BlockSize {
  65                 panic("crypto/aes: output not full block")
  66         }
  67         decryptBlockAsm(len(c.dec)/4-1, &c.dec[0], &dst[0], &src[0])
  68 }
  69
  70 // expandKey is used by BenchmarkExpand to ensure that the asm implementation
  71 // of key expansion is used for the benchmark when it is available.
  72 func expandKey(key []byte, enc, dec []uint32) {
  73         if useAsm {
  74                 rounds := 10 // rounds needed for AES128
  75                 switch len(key) {
  76                 case 192 / 8:
  77                         rounds = 12
  78                 case 256 / 8:
  79                         rounds = 14
  80                 }
  81                 expandKeyAsm(rounds, &key[0], &enc[0], &dec[0])
  82         } else {
  83                 expandKeyGo(key, enc, dec)
  84         }
  85 }