-/* xtea-asm.S */
+/* xtea-enc.S */
/*
- This file is part of the AVR-Crypto-Lib.
- Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
+ This file is part of the ARM-Crypto-Lib.
+ Copyright (C) 2006-2011 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
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-/* xtea-asm.S
- * Author: Daniel Otte
- * Date: 2006-06-06
- * License: GPLv3 or later
- * Implementation of XTEA for AVR
- * include xtea.h in your C-Project to use this functions.
-*/
-V01 = 2
-V02 = 3
-V03 = 4
-V04 = 5
-V11 = 6
-V12 = 7
-V13 = 8
-V14 = 9
-Accu1 = 14
-Accu2 = 15
-Accu3 = 16
-Accu4 = 17
-Sum1 = 18
-Sum2 = 19
-Sum3 = 20
-Sum4 = 21
-Func1 = 22
-Func2 = 23
-Func3 = 24
-Func4 = 25
-C = 28 /* der kleine Zaehler fuer zwischendurch */
+#include "avr-asm-macros.S"
+
+B0 = 4
+B1 = 5
+B2 = 6
+B3 = 7
+
+A0 = 8
+A1 = 9
+A2 = 10
+A3 = 11
+
+V10 = 12
+V11 = 13
+V12 = 14
+V13 = 15
+
+V00 = 16
+V01 = 17
+V02 = 18
+V03 = 19
+
+S0 = 20
+S1 = 21
+S2 = 22
+S3 = 23
+
+xchg_V0V1:
+ movw r26, V10
+ movw V10, V00
+ movw V00, r26
+ movw r26, V12
+ movw V12, V02
+ movw V02, r26
+ ret
+
+eor_AB:
+ eor A0, B0
+ eor A1, B1
+ eor A2, B2
+ eor A3, B3
+ ret
+
+g_func:
+ movw A0, V10
+ movw A2, V12
+ movw B0, V10
+ movw B2, V12
+
+ ldi r24, 4
+10:
+ lsl A0
+ rol A1
+ rol A2
+ rol A3
+ dec r24
+ brne 10b
+
+ ldi r24, 5
+10:
+ lsr B3
+ ror B2
+ ror B1
+ ror B0
+ dec r24
+ brne 10b
+
+ rcall eor_AB
+
+ add A0, V10
+ adc A1, V11
+ adc A2, V12
+ adc A3, V13
+
+ ret
+
+sum_plus_k:
+ andi r24, (3<<2)
+ movw r26, r30
+ add r26, r24
+ adc r27, r1
+ ld B0, X+
+ ld B1, X+
+ ld B2, X+
+ ld B3, X+
+ add B0, S0
+ adc B1, S1
+ adc B2, S2
+ adc B3, S3
+ rcall eor_AB
+ brtc 20f
+ add V00, A0
+ adc V01, A1
+ adc V02, A2
+ adc V03, A3
+ ret
+20: sub V00, A0
+ sbc V01, A1
+ sbc V02, A2
+ sbc V03, A3
+ ret
+
+main1:
+ rcall g_func
+ mov r24, S0
+ lsl r24
+ lsl r24
+ rcall sum_plus_k
+ ret
+
+main2:
+ rcall xchg_V0V1
+ rcall g_func
+ mov r24, S1
+ lsr r24
+ rcall sum_plus_k
+ rcall xchg_V0V1
+ ret
.global xtea_enc
-; == xtea_enc ==
-; xtea encrytion function
-; param1: 16-bit pointer to destination for encrypted block
-; given in r25,r24
-; param2: 16-bit pointer to the block (64-bit) which is to encrypt
-; given in r23,r22
-; param3: 16-bit pointer to the key (128-bit)
-; given in r21,r20
-;
xtea_enc:
- /* prolog */
- push r2
- push r3
- push r4
- push r5
- push r6
- push r7
- push r8
- push r9
- push r14
- push r15
- push r16
- push r17
- push r28
-
- /* load the block */
- movw r26, r22 /* X points to block */
- movw r30, r20 /* Z points to key */
- ld V01, X+
- ld V02, X+
- ld V03, X+
- ld V04, X+
- ld V11, X+
- ld V12, X+
- ld V13, X+
- ld V14, X+
-; push r25
-; push r24
- movw r26, r24 /* X points to destination */
-
- ldi Func1, 32
- mov r0, Func1 /* r0 is cycle-counter */
- clr Sum1
- clr Sum2
- movw Sum3, Sum1
- clt
-
-1:
- movw Accu1, V11
- movw Accu3, V13
- ldi C, 4
-2: lsl Accu1
- rol Accu2
- rol Accu3
- rol Accu4
- dec C
- brne 2b /* Accu == V1 << 4 */
-
- movw Func1, V11
- movw Func3, V13
- ldi C, 5
-3: lsr Func4
- ror Func3
- ror Func2
- ror Func1
- dec C
- brne 3b /* Func == V1 >> 5 */
-
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4
- add Accu1, V11
- adc Accu2, V12
- adc Accu3, V13
- adc Accu4, V14 /* Accu == ( (V1<<4)^(V1>>5) ) + V1 */
-
- brtc 4f
- mov C, Sum2
- lsr C
- andi C,(0x03 <<2)
- clt
- rjmp 5f
-4:
- mov C, Sum1 /* calc key offset */
- andi C, 0x03
- lsl C
- lsl C
set
-
-5:
- add r30, C
- adc r31, r1
- ld Func1, Z
- ldd Func2, Z+1
- ldd Func3, Z+2
- ldd Func4, Z+3 /* Func = key[sum & 3] */
- sub r30, C
- sbci r31, 0
- add Func1, Sum1
- adc Func2, Sum2
- adc Func3, Sum3
- adc Func4, Sum4
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4 /* Accu = ((V1<<4 ^ V1>>5) + V1) ^ (sum + key[sum&3]) */
- add Accu1, V01
- adc Accu2, V02
- adc Accu3, V03
- adc Accu4, V04
-
- movw V01, V11
- movw V03, V13
- movw V11, Accu1
- movw V13, Accu3
-
- /* sum += delta */ /* delta == 0x9E3779B9 */
- brtc 6f
- ldi C, 0xB9
- add Sum1, C
- ldi C, 0x79
- adc Sum2, C
- ldi C, 0x37
- adc Sum3, C
- ldi C, 0x9E
- adc Sum4, C
- rjmp 1b
-
-6:
+xtea_intro:
+ clr r27
+ ldi r26, 4
+ ldi r30, 14
+10:
+ ld r0, X+
+ push r0
+ dec r30
+ brne 10b
+
+ push r24
+ push r25
+ movw r30, r20
+/* load block */
+ movw r26, r22
+ ld V00, X+
+ ld V01, X+
+ ld V02, X+
+ ld V03, X+
+ ld V10, X+
+ ld V11, X+
+ ld V12, X+
+ ld V13, X+
+ ldi r24, 32
+ mov r0, r24
+ brtc xtea_dec_start
+ clr S0
+ clr S1
+ movw S2, S0
+
+10:
+ rcall main1
+ subi S0, 0x47
+ sbci S1, 0x86
+ sbci S2, 0xC8
+ sbci S3, 0x61
+ rcall main2
+
dec r0
- breq 7f
- rjmp 1b
-
- 7:
- /* write block back */
- ; pop r26
- ; pop r27
- st X+, V01
- st X+, V02
- st X+, V03
- st X+, V04
- st X+, V11
- st X+, V12
- st X+, V13
- st X+, V14
-
- /* epilog */
- pop r28
- pop r17
- pop r16
- pop r15
- pop r14
- pop r9
- pop r8
- pop r7
- pop r6
- pop r5
- pop r4
- pop r3
- pop r2
- ret
-
-;####################################################################
-
- /* #endif TWO_IN_ONE */
-
- /* #ifdef TWO_IN_ONE */
- /* now we use the same base-structure for enc- and decryption
- to indicate operation mode we use the highest bit of param3 (16 bit pointer to key),
- this is ok, since even the larges atmel today has "only" 8k of ram,
- but you shouldn't use this feature while using external ram.
- */
-.global xtea_enc
- ori r21, 0x80
-
-.global xtea_dec
-; == xtea_dec ==
-; xtea decrytion function
-; param1: 16-bit pointer to destination for decrypted block
-; given in r25,r24
-; param2: 16-bit pointer to the block (64-bit) which is to derypt
-; given in r23,r22
-; param3: 16-bit pointer to the key (128-bit)
-; given in r21,r20
-;
-/*
-void xtea_dec(uint32_t* dest, uint32_t* v, uint32_t* k) {
- uint32_t v0=v[0], v1=v[1], i;
- uint32_t sum=0xC6EF3720, delta=0x9E3779B9;
- for(i=0; i<32; i++) {
- v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
- sum -= delta;
- v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
- }
- dest[0]=v0; dest[1]=v1;
-}
-*/
+ brne 10b
+
+/* store back */
+xtea_enc_exit:
+ pop r27
+ pop r26
+ st X+, V00
+ st X+, V01
+ st X+, V02
+ st X+, V03
+ st X+, V10
+ st X+, V11
+ st X+, V12
+ st X+, V13
+
+ clr r27
+ ldi r26, 18
+ ldi r24, 14
+10:
+ pop r0
+ st -X, r0
+ dec r24
+ brne 10b
+ ret
+
+
+/******************************************************************************/
+/******************************************************************************/
+/******************************************************************************/
+/******************************************************************************/
+.global xtea_dec
xtea_dec:
- /* prolog */
- push r2
- push r3
- push r4
- push r5
- push r6
- push r7
- push r8
- push r9
- push r14
- push r15
- push r16
- push r17
- push r28
- /* load the block */
- movw r26, r22 /* Z points to block */
- movw r30, r20 /* X points to key */
- ld V01, X+
- ld V02, X+
- ld V03, X+
- ld V04, X+
- ld V11, X+
- ld V12, X+
- ld V13, X+
- ld V14, X+
- movw r26, r24 /* Z points to destination */
-
- ldi Sum1, 32
- mov r0, Sum1 /* r1 is cycle-counter */
- ldi Sum1, 0x20 /* sum = 0xC6EF3720 */
- ldi Sum2, 0x37
- ldi Sum3, 0xEF
- ldi Sum4, 0xC6
clt
+ rjmp xtea_intro
+xtea_dec_start:
+ ldi S0, 0x20 /* sum = 0xC6EF3720 */
+ ldi S1, 0x37
+ ldi S2, 0xEF
+ ldi S3, 0xC6
+
+10:
+ rcall main2
+ subi S0, 0xB9
+ sbci S1, 0x79
+ sbci S2, 0x37
+ sbci S3, 0x9E
+ rcall main1
-1:
- movw Accu1, V01
- movw Accu3, V03
- ldi C, 4
-2: lsl Accu1
- rol Accu2
- rol Accu3
- rol Accu4
- dec C
- brne 2b /* Accu == V0 << 4 */
-
- movw Func1, V01
- movw Func3, V03
- ldi C, 5
-3: lsr Func4
- ror Func3
- ror Func2
- ror Func1
- dec C
- brne 3b /* Func == V0 >> 5 */
-
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4
- add Accu1, V01
- adc Accu2, V02
- adc Accu3, V03
- adc Accu4, V04 /* Accu == ( (V0<<4)^(V0>>5) ) + V0 */
-
- brts 4f
- mov C, Sum2
- lsr C
- andi C,(0x03 <<2)
- set
- rjmp 5f
-4:
- mov C, Sum1 /* calc key offset */
- andi C, 0x03
- lsl C
- lsl C
- clt
-
-5:
- add r30, C
- adc r31, r1
- ld Func1, Z
- ldd Func2, Z+1
- ldd Func3, Z+2
- ldd Func4, Z+3 /* Func = key[sum & 3] */
- sub r30, C
- sbci r31, 0
- add Func1, Sum1
- adc Func2, Sum2
- adc Func3, Sum3
- adc Func4, Sum4
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4 /* Accu = ((V0<<4 ^ V0>>5) + V0) ^ (sum + key[sum&3]) */
- sub V11, Accu1
- sbc V12, Accu2
- sbc V13, Accu3
- sbc V14, Accu4
-
- movw Accu1, V01
- movw Accu3, V03
- movw V01, V11
- movw V03, V13
- movw V11, Accu1
- movw V13, Accu3
-
- /* sum += delta */ /* delta == 0x9E3779B9 */
- brtc 6f
- subi Sum1, 0xB9
- sbci Sum2, 0x79
- sbci Sum3, 0x37
- sbci Sum4, 0x9E
- rjmp 1b
-
-6:
dec r0
- breq 7f
- rjmp 1b
-
-7:
- /* write block back */
- st X+, V01
- st X+, V02
- st X+, V03
- st X+, V04
- st X+, V11
- st X+, V12
- st X+, V13
- st X+, V14
-
- /* epilog */
- pop r28
- pop r17
- pop r16
- pop r15
- pop r14
- pop r9
- pop r8
- pop r7
- pop r6
- pop r5
- pop r4
- pop r3
- pop r2
- ret
-
- /* #endif */
-
-;####################################################################
-
- #ifdef TWO_IN_ONE
- /* now we use the same base-structure for enc- and decryption
- to indicate operation mode we use the highest bit of param3 (16 bit pointer to key),
- this is ok, since even the larges atmel today has "only" 8k of ram,
- but you shouldn't use this feature while using external ram.
- */
-.global xtea_enc
- ori r21, 0x80
-
-.global xtea_dec
-; == xtea_dec ==
-; xtea decrytion function
-; param1: 16-bit pointer to destination for decrypted block
-; given in r25,r24
-; param2: 16-bit pointer to the block (64-bit) which is to derypt
-; given in r23,r22
-; param3: 16-bit pointer to the key (128-bit)
-; given in r21,r20
-;
-/*
-void xtea_dec(uint32_t* dest, uint32_t* v, uint32_t* k) {
- uint32_t v0=v[0], v1=v[1], i;
- uint32_t sum=0xC6EF3720, delta=0x9E3779B9;
- for(i=0; i<32; i++) {
- v1 -= ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
- sum -= delta;
- v0 -= ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
- }
- dest[0]=v0; dest[1]=v1;
-}
-*/
+ brne 10b
+/* store back */
+ rjmp xtea_enc_exit
-xtea_dec:
- /* prolog */
- push r2
- push r3
- push r4
- push r5
- push r6
- push r7
- push r8
- push r9
- push r14
- push r15
- push r16
- push r17
- push r28
- /* set T-bit if we are going to encrypt, clear otherwise */
- bst r21, 7
- andi r21, 0x7f /* fix r21:r22 to a real addr */
- /* load the block */
- movw r26, r22 /* Z points to block */
- movw r30, r20 /* X points to key */
- ld V01, X+
- ld V02, X+
- ld V03, X+
- ld V04, X+
- ld V11, X+
- ld V12, X+
- ld V13, X+
- ld V14, X+
- movw r26, r24 /* Z points to destination */
-
- ldi Sum1, 32
- mov r0, Sum1 /* r1 is cycle-counter */
- ldi Sum1, 0x20 /* sum = 0xC6EF3720 */
- ldi Sum2, 0x37
- ldi Sum3, 0xEF
- ldi Sum4, 0xC6
- clt
-1:
- movw Accu1, V01
- movw Accu3, V03
- ldi C, 4
-2: lsl Accu1
- rol Accu2
- rol Accu3
- rol Accu4
- dec C
- brne 2b /* Accu == V0 << 4 */
-
- movw Func1, V01
- movw Func3, V03
- ldi C, 5
-3: lsr Func4
- ror Func3
- ror Func2
- ror Func1
- dec C
- brne 3b /* Func == V0 >> 5 */
-
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4
- add Accu1, V01
- adc Accu2, V02
- adc Accu3, V03
- adc Accu4, V04 /* Accu == ( (V0<<4)^(V0>>5) ) + V0 */
-
- brts 4f
- mov C, Sum2
- lsr C
- andi C,(0x03 <<2)
- set
- rjmp 5f
-4:
- mov C, Sum1 /* calc key offset */
- andi C, 0x03
- lsl C
- lsl C
- clt
-
-5:
- add r30, C
- adc r31, r1
- ld Func1, Z
- ldd Func2, Z+1
- ldd Func3, Z+2
- ldd Func4, Z+3 /* Func = key[sum & 3] */
- sub r30, C
- sbci r31, 0
- add Func1, Sum1
- adc Func2, Sum2
- adc Func3, Sum3
- adc Func4, Sum4
- eor Accu1, Func1
- eor Accu2, Func2
- eor Accu3, Func3
- eor Accu4, Func4 /* Accu = ((V0<<4 ^ V0>>5) + V0) ^ (sum + key[sum&3]) */
- sub V11, Accu1
- sbc V12, Accu2
- sbc V13, Accu3
- sbc V14, Accu4
-
- movw Accu1, V01
- movw Accu3, V03
- movw V01, V11
- movw V03, V13
- movw V11, Accu1
- movw V13, Accu3
-
- /* sum += delta */ /* delta == 0x9E3779B9 */
- brtc 6f
- subi Sum1, 0xB9
- sbci Sum2, 0x79
- sbci Sum3, 0x37
- sbci Sum4, 0x9E
- rjmp 1b
-
-6:
- dec r0
- breq 7f
- rjmp 1b
-
-7:
- /* write block back */
- st X+, V01
- st X+, V02
- st X+, V03
- st X+, V04
- st X+, V11
- st X+, V12
- st X+, V13
- st X+, V14
-
- /* epilog */
- pop r28
- pop r17
- pop r16
- pop r15
- pop r14
- pop r9
- pop r8
- pop r7
- pop r6
- pop r5
- pop r4
- pop r3
- pop r2
- ret
-
- #endif
projects / avr-crypto-lib.git / blobdiff