release/src/router/nettle/sparc32/aes-decrypt-internal.asm

   1 C -*- mode: asm; asm-comment-char: ?C; -*-
   2 C nettle, low-level cryptographics library
   3 C
   4 C Copyright (C) 2002, 2005 Niels Möller
   5 C
   6 C The nettle library is free software; you can redistribute it and/or modify
   7 C it under the terms of the GNU Lesser General Public License as published by
   8 C the Free Software Foundation; either version 2.1 of the License, or (at your
   9 C option) any later version.
  10 C
  11 C The nettle library is distributed in the hope that it will be useful, but
  12 C WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13 C or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
  14 C License for more details.
  15 C
  16 C You should have received a copy of the GNU Lesser General Public License
  17 C along with the nettle library; see the file COPYING.LIB.  If not, write to
  18 C the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  19 C MA 02111-1301, USA.
  20
  21 include_src(<sparc32/aes.m4>)
  22
  23 C       Arguments
  24 define(<CTX>,   <%i0>)
  25 define(<T>,     <%i1>)
  26 define(<LENGTH>,<%i2>)
  27 define(<DST>,   <%i3>)
  28 define(<SRC>,   <%i4>)
  29
  30 C       AES state, two copies for unrolling
  31
  32 define(<W0>,    <%l0>)
  33 define(<W1>,    <%l1>)
  34 define(<W2>,    <%l2>)
  35 define(<W3>,    <%l3>)
  36
  37 define(<X0>,    <%l4>)
  38 define(<X1>,    <%l5>)
  39 define(<X2>,    <%l6>)
  40 define(<X3>,    <%l7>)
  41
  42 C       %o0-%03 are used for loop invariants T0-T3
  43 define(<KEY>,   <%o4>)
  44 define(<ROUND>, <%o5>)
  45
  46 C %g1, %g2, %g3 are TMP1, TMP2 and TMP3
  47
  48 C The sparc32 stack frame looks like
  49 C
  50 C %fp -   4: OS-dependent link field
  51 C %fp -   8: OS-dependent link field
  52 C %fp - 104: OS register save area.
  53 define(<FRAME_SIZE>, 104)
  54
  55         .file "aes-decrypt-internal.asm"
  56
  57         C _aes_decrypt(struct aes_context *ctx,
  58         C              const struct aes_table *T,
  59         C              unsigned length, uint8_t *dst,
  60         C              uint8_t *src)
  61
  62         .section        ".text"
  63         .align 16
  64         .proc   020
  65
  66 PROLOGUE(_nettle_aes_decrypt)
  67
  68         save    %sp, -FRAME_SIZE, %sp
  69         cmp     LENGTH, 0
  70         be      .Lend
  71
  72         C       Loop invariants
  73         add     T, AES_TABLE0, T0
  74         add     T, AES_TABLE1, T1
  75         add     T, AES_TABLE2, T2
  76         add     T, AES_TABLE3, T3
  77
  78 .Lblock_loop:
  79         C  Read src, and add initial subkey
  80         add     CTX, AES_KEYS, KEY
  81         AES_LOAD(0, SRC, KEY, W0)
  82         AES_LOAD(1, SRC, KEY, W1)
  83         AES_LOAD(2, SRC, KEY, W2)
  84         AES_LOAD(3, SRC, KEY, W3)
  85
  86         C       Must be even, and includes the final round
  87         ld      [AES_NROUNDS + CTX], ROUND
  88         add     SRC, 16, SRC
  89         add     KEY, 16, KEY
  90
  91         srl     ROUND, 1, ROUND
  92         C       Last two rounds handled specially
  93         sub     ROUND, 1, ROUND
  94 .Lround_loop:
  95         C The AES_ROUND macro uses T0,... T3
  96         C       Transform W -> X
  97         AES_ROUND(0, W0, W3, W2, W1, KEY, X0)
  98         AES_ROUND(1, W1, W0, W3, W2, KEY, X1)
  99         AES_ROUND(2, W2, W1, W0, W3, KEY, X2)
 100         AES_ROUND(3, W3, W2, W1, W0, KEY, X3)
 101
 102         C       Transform X -> W
 103         AES_ROUND(4, X0, X3, X2, X1, KEY, W0)
 104         AES_ROUND(5, X1, X0, X3, X2, KEY, W1)
 105         AES_ROUND(6, X2, X1, X0, X3, KEY, W2)
 106         AES_ROUND(7, X3, X2, X1, X0, KEY, W3)
 107
 108         subcc   ROUND, 1, ROUND
 109         bne     .Lround_loop
 110         add     KEY, 32, KEY
 111
 112         C       Penultimate round
 113         AES_ROUND(0, W0, W3, W2, W1, KEY, X0)
 114         AES_ROUND(1, W1, W0, W3, W2, KEY, X1)
 115         AES_ROUND(2, W2, W1, W0, W3, KEY, X2)
 116         AES_ROUND(3, W3, W2, W1, W0, KEY, X3)
 117
 118         add     KEY, 16, KEY
 119         C       Final round
 120         AES_FINAL_ROUND(0, T, X0, X3, X2, X1, KEY, DST)
 121         AES_FINAL_ROUND(1, T, X1, X0, X3, X2, KEY, DST)
 122         AES_FINAL_ROUND(2, T, X2, X1, X0, X3, KEY, DST)
 123         AES_FINAL_ROUND(3, T, X3, X2, X1, X0, KEY, DST)
 124
 125         subcc   LENGTH, 16, LENGTH
 126         bne     .Lblock_loop
 127         add     DST, 16, DST
 128
 129 .Lend:
 130         ret
 131         restore
 132 EPILOGUE(_nettle_aes_decrypt)