+/* aes_keyschedule-asm */
+/*
+ This file is part of the AVR-Crypto-Lib.
+ Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
+
+ 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 <http://www.gnu.org/licenses/>.
+*/
+/**
+ * \file aes_keyschedule-asm.S
+ * \email bg@nerilex.org
+ * \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;i<hi;++i){
+ *((uint32_t*)tmp) = ((uint32_t*)(ctx->key[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
+ /* NK is now the number of 32-bit words in the supplied key */
+ bst NK, 3 /* set T if NK==8 */
+ mov NEXT_NK, NK
+ mov HI, NK
+ subi HI, -7 /* HI += 7 */
+ lsl HI
+ lsl HI
+ movw r26, r30
+ sbiw r26, 4
+ mov C1, NK
+ 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
+ rcall substitute
+ rjmp 5f
+2:
+ add NEXT_NK, NK
+ rcall substitute
+ mov r16, T0
+ mov T0, T1
+ mov T1, T2
+ mov T2, T3
+ 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
+
+substitute:
+ ldi r31, hi8(aes_sbox)
+ mov r30, T0
+ lpm T0, Z
+ mov r30, T1
+ lpm T1, Z
+ mov r30, T2
+ lpm T2, Z
+ mov r30, T3
+ lpm T3, Z
+ ret
+
+