/* aes_keyschedule-asm */
/*
This file is part of the AVR-Crypto-Lib.
Copyright (C) 2008, 2009 Daniel Otte (daniel.otte@rub.de)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 a copy of the GNU General Public License
along with this program. If not, see .
*/
/**
* \file aes_keyschedule-asm.S
* \email daniel.otte@rub.de
* \author Daniel Otte
* \date 2009-01-09
* \license GPLv3 or later
*
*/
#include "avr-asm-macros.S"
.global aes256_init
aes256_init:
movw r20, r22
ldi r23, hi8(256)
ldi r22, lo8(256)
rjmp aes_init
.global aes192_init
aes192_init:
movw r20, r22
ldi r23, hi8(192)
ldi r22, lo8(192)
rjmp aes_init
.global aes128_init
aes128_init:
movw r20, r22
clr r23
ldi r22, 128
/*
void aes_init(const void* key, uint16_t keysize_b, aes_genctx_t* ctx){
uint8_t hi,i,nk, next_nk;
uint8_t rc=1;
uint8_t tmp[4];
nk=keysize_b>>5; / * 4, 6, 8 * /
hi=4*(nk+6+1);
memcpy(ctx, key, keysize_b/8);
next_nk = nk;
for(i=nk;ikey[0].ks))[i-1];
if(i!=next_nk){
if(nk==8 && i%8==4){
tmp[0] = pgm_read_byte(aes_sbox+tmp[0]);
tmp[1] = pgm_read_byte(aes_sbox+tmp[1]);
tmp[2] = pgm_read_byte(aes_sbox+tmp[2]);
tmp[3] = pgm_read_byte(aes_sbox+tmp[3]);
}
} else {
next_nk += nk;
aes_rotword(tmp);
tmp[0] = pgm_read_byte(aes_sbox+tmp[0]);
tmp[1] = pgm_read_byte(aes_sbox+tmp[1]);
tmp[2] = pgm_read_byte(aes_sbox+tmp[2]);
tmp[3] = pgm_read_byte(aes_sbox+tmp[3]);
tmp[0] ^= rc;
rc<<=1;
}
((uint32_t*)(ctx->key[0].ks))[i] = ((uint32_t*)(ctx->key[0].ks))[i-nk]
^ *((uint32_t*)tmp);
}
}
*/
SBOX_SAVE0 = 14
SBOX_SAVE1 = 15
XRC = 17
NK = 22
C1 = 18
NEXT_NK = 19
HI = 23
T0 = 20
T1 = 21
T2 = 24
T3 = 25
/*
* param key: r24:r25
* param keysize_b: r22:r23
* param ctx: r20:r21
*/
.global aes_init
aes_init:
push_range 14, 17
push r28
push r29
movw r30, r20
movw r28, r20
movw r26, r24
lsr r23
ror r22
lsr r22
lsr r22 /* r22 contains keysize_b/8 */
mov C1, r22
1: /* copy key to ctx */
ld r0, X+
st Z+, r0
dec C1
brne 1b
lsr NK
lsr NK
bst NK,3 /* set T if NK==8 */
mov NEXT_NK, NK
mov HI, NK
subi HI, -7
lsl HI
lsl HI
movw r26, r30
sbiw r26, 4
mov C1, NK
ldi r30, lo8(aes_sbox)
ldi r31, hi8(aes_sbox)
movw SBOX_SAVE0, r30
ldi XRC, 1
1:
ld T0, X+
ld T1, X+
ld T2, X+
ld T3, X+
cp NEXT_NK, C1
breq 2f
brtc 5f
mov r16, C1
andi r16, 0x07
cpi r16, 0x04
brne 5f
movw r30, SBOX_SAVE0
add r30, T0
adc r31, r1
lpm T0, Z
movw r30, SBOX_SAVE0
add r30, T1
adc r31, r1
lpm T1, Z
movw r30, SBOX_SAVE0
add r30, T2
adc r31, r1
lpm T2, Z
movw r30, SBOX_SAVE0
add r30, T3
adc r31, r1
lpm T3, Z
rjmp 5f
2:
add NEXT_NK, NK
movw r30, SBOX_SAVE0
add r30, T0
adc r31, r1
lpm r16, Z
movw r30, SBOX_SAVE0
add r30, T1
adc r31, r1
lpm T0, Z
movw r30, SBOX_SAVE0
add r30, T2
adc r31, r1
lpm T1, Z
movw r30, SBOX_SAVE0
add r30, T3
adc r31, r1
lpm T2, Z
mov T3, r16
eor T0, XRC
lsl XRC
brcc 3f
ldi XRC, 0x1b
3:
5:
movw r30, r26
ld r0, Y+
eor r0, T0
st Z+, r0
ld r0, Y+
eor r0 ,T1
st Z+, r0
ld r0, Y+
eor r0, T2
st Z+, r0
ld r0, Y+
eor r0, T3
st Z+, r0
/*
st Z+, T0
st Z+, T1
st Z+, T2
st Z+, T3
*/
inc C1
cp C1, HI
breq 6f
rjmp 1b
6:
clt
pop r29
pop r28
pop_range 14, 17
ret