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C x86/aes-encrypt-internal.asm
ifelse(`
Copyright (C) 2001, 2002, 2005, Rafael R. Sevilla, Niels Möller
Copyright (C) 2008, 2013 Niels Möller
This file is part of GNU Nettle.
GNU Nettle is free software: you can redistribute it and/or
modify it under the terms of either:
* the GNU Lesser General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your
option) any later version.
or
* the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version.
or both in parallel, as here.
GNU Nettle is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received copies of the GNU General Public License and
the GNU Lesser General Public License along with this program. If
not, see http://www.gnu.org/licenses/.
')
include_src(`x86/aes.m4')
C Register usage:
C AES state
define(`SA',`%eax')
define(`SB',`%ebx')
define(`SC',`%ecx')
define(`SD',`%edx')
C Primary use of these registers. They're also used temporarily for other things.
define(`T',`%ebp')
define(`TMP',`%edi')
define(`KEY',`%esi')
define(`PARAM_ROUNDS', `40(%esp)')
define(`PARAM_KEYS', `44(%esp)')
define(`PARAM_TABLE', `48(%esp)')
define(`PARAM_LENGTH', `52(%esp)')
define(`PARAM_DST', `56(%esp)')
define(`PARAM_SRC', `60(%esp)')
define(`FRAME_KEY', `16(%esp)')
define(`FRAME_COUNT', `12(%esp)')
define(`TA', `8(%esp)')
define(`TB', `4(%esp)')
define(`TC', `(%esp)')
C The aes state is kept in %eax, %ebx, %ecx and %edx
C
C %esi is used as temporary, to point to the input, and to the
C subkeys, etc.
C
C %ebp is used as the round counter, and as a temporary in the final round.
C
C %edi is a temporary, often used as an accumulator.
.file "aes-encrypt-internal.asm"
C _aes_encrypt(unsigned rounds, const uint32_t *keys,
C const struct aes_table *T,
C size_t length, uint8_t *dst,
C uint8_t *src)
.text
ALIGN(16)
PROLOGUE(_nettle_aes_encrypt)
C save all registers that need to be saved
pushl %ebx C 20(%esp)
pushl %ebp C 16(%esp)
pushl %esi C 12(%esp)
pushl %edi C 8(%esp)
subl $20, %esp C loop counter and save area for the key pointer
movl PARAM_LENGTH, %ebp
testl %ebp,%ebp
jz .Lend
shrl $4, PARAM_LENGTH
subl $1, PARAM_ROUNDS
.Lblock_loop:
movl PARAM_KEYS, KEY C address of subkeys
movl PARAM_SRC, TMP C address of plaintext
AES_LOAD(SA, SB, SC, SD, TMP, KEY)
addl $16, PARAM_SRC C Increment src pointer
movl PARAM_TABLE, T
movl PARAM_ROUNDS, TMP
C Loop counter on stack
movl TMP, FRAME_COUNT
addl $16,KEY C point to next key
movl KEY,FRAME_KEY
ALIGN(16)
.Lround_loop:
AES_ROUND(T, SA,SB,SC,SD, TMP, KEY)
movl TMP, TA
AES_ROUND(T, SB,SC,SD,SA, TMP, KEY)
movl TMP, TB
AES_ROUND(T, SC,SD,SA,SB, TMP, KEY)
movl TMP, TC
AES_ROUND(T, SD,SA,SB,SC, SD, KEY)
movl TA, SA
movl TB, SB
movl TC, SC
movl FRAME_KEY, KEY
xorl (KEY),SA C add current session key to plaintext
xorl 4(KEY),SB
xorl 8(KEY),SC
xorl 12(KEY),SD
addl $16,FRAME_KEY C point to next key
decl FRAME_COUNT
jnz .Lround_loop
C last round
AES_FINAL_ROUND(SA,SB,SC,SD, T, TMP, KEY)
movl TMP, TA
AES_FINAL_ROUND(SB,SC,SD,SA, T, TMP, KEY)
movl TMP, TB
AES_FINAL_ROUND(SC,SD,SA,SB, T, TMP, KEY)
movl TMP, TC
AES_FINAL_ROUND(SD,SA,SB,SC, T, SD, KEY)
movl TA, SA
movl TB, SB
movl TC, SC
C S-box substitution
mov $3,TMP
.Lsubst:
AES_SUBST_BYTE(SA,SB,SC,SD, T, KEY)
decl TMP
jnz .Lsubst
C Add last subkey, and store encrypted data
movl PARAM_DST,TMP
movl FRAME_KEY, KEY
AES_STORE(SA,SB,SC,SD, KEY, TMP)
addl $16, PARAM_DST C Increment destination pointer
decl PARAM_LENGTH
jnz .Lblock_loop
.Lend:
addl $20, %esp
popl %edi
popl %esi
popl %ebp
popl %ebx
ret
EPILOGUE(_nettle_aes_encrypt)
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