176 lines
3.0 KiB
ArmAsm
176 lines
3.0 KiB
ArmAsm
/* noekeon_omac.S */
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/*
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This file is part of the Crypto-avr-lib/microcrypt-lib.
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Copyright (C) 2008 Daniel Otte (daniel.otte@rub.de)
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* \author Daniel Otte
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* \email daniel.otte@rub.de
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* \date 2008-08-06
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* \license GPLv3 or later
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*
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*
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*
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*/
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#include <avr/io.h>
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#include "avr-asm-macros.S"
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push_r18_r27_func:
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pop r31
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pop r30
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push_range 18, 27
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ijmp
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pop_r18_r27_func:
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pop r31
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pop r30
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pop_range 18, 27
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ijmp
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.extern noekeon_enc
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/*
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* void noekeon_omac(void* dest, const void* msg, uint16_t msglength_b,
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* const void* key, uint8_t t)
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*/
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/* param dest is passed in r24:r25
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* param msg is passed in r22:r23
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* param msglength_b is passed in r20:r21
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* param key is passed in r18:r19
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* param t is passed in r16
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*/
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.global noekeon_omac
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noekeon_omac:
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stack_alloc 48
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adiw r30, 1
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ldi r17, 48
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1:
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st Z+, r1
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dec r17
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brne 1b
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sbiw r30, 48
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movw r26, r22
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movw r22, r18
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movw r18, r24
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movw r24, r30
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cpi r16, 0xff
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breq 2f
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st Z, r16
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rcall push_r18_r27_func
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rcall noekeon_enc
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rcall pop_r18_r27_func
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movw r30, r24
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2:
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tst r21
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brne fullblock
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cpi r20, 128+1
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brlo lastblock
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fullblock:
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/* copy block to stack buffer */
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ldi r16, 16
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1:
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ld r0, X+
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ld r17, Z
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eor r0, r17
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st Z+, r0
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dec r16
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brne 1b
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rcall push_r18_r27_func
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rcall noekeon_enc
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rcall pop_r18_r27_func
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movw r30, r24
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subi r20, 128
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sbci r21, 0
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rjmp 2
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lastblock:
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adiw r24, 16
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rcall push_r18_r27_func
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rcall noekeon_enc
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rcall pop_r18_r27_func
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bst r20, 6 /* set t bit if msglength_b%128==0*/
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2:
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ldi r16, 16
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clc
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movw r30, r24 /* z points to encrypted null vector (L) */
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1:
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ld r0, Z
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rol r0
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st Z+, r0
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dec r16
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brne 1b
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brtc 2f
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clt
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rjmp 2b
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2: /* B/P has been calculated */
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ldi r16, 16
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sbiw r30, 32
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3:
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ld r0, Z
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ldd r17, Z+16
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eor r0, r17
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st Z+, r0
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dec r16
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brne 3b
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/* B/P has been xored into stack buffer */
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/* now we have to xor-in the remaining message */
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mov r16, r20
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subi r16, -7
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lsr r16
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lsr r16
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lsr r16 /* r 1*/
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sbiw r30, 16
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4:
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ld r0, X+
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ld r17, Z
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eor r0, r17
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st Z+, r0
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dec r16
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brne 4b
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/* now we have only to insert the 1 at the end of message if msglength_b%128 != 0 */
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sbiw r30, 1
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andi r20, 0x07
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breq 7f
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ldi r17, 1
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5:
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dec r20
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breq 6f
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lsl r17
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rjmp 5b
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6:
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ld r0, Z
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eor r0, r17
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st Z, r0
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7:
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call noekeon_enc
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stack_free 48
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ret
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