-/* threefish256_enc_asm.S */
-/*
- This file is part of the AVR-Crypto-Lib.
- Copyright (C) 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 <http://www.gnu.org/licenses/>.
-*/
-/*
- * \author Daniel Otte
- * \email daniel.otte@rub.de
- * \date 2009-03-16
- * \license GPLv3 or later
- */
-
-#include "avr-asm-macros.S"
-
-/******************************************************************************/
-/*
-void permute_4(void* data){
- uint64_t t;
- t = X(1);
- X(1) = X(3);
- X(3) = t;
-}
-void add_key_4(void* data, const threefish256_ctx_t* ctx, uint8_t s){
- X(0) -= ctx->k[(s+0)%5];
- X(1) -= ctx->k[(s+1)%5] + ctx->t[s%3];
- X(2) -= ctx->k[(s+2)%5] + ctx->t[(s+1)%3];
- X(3) -= ctx->k[(s+3)%5] + s;
-}
-void threefish256_dec(void* data, const threefish256_ctx_t* ctx){
- uint8_t i=0,s=18;
- uint8_t r0[8] = {0x73, 0x13, 0x7b, 0x32, 0x72, 0x2b, 0x44, 0x1b};
- uint8_t r1[8] = {0x62, 0x52, 0x43, 0x24, 0x54, 0x6a, 0x34, 0x70};
- do{
- if(i%4==0){
- add_key_4(data, ctx, s);
- --s;
- }
- permute_4(data);
- threefish_invmix(data, r0[i%8]);
- threefish_invmix((uint8_t*)data + 16, r1[i%8]);
- ++i;
- }while(i!=72);
- add_key_4(data, ctx, s);
-}
-*/
-I = 2
-S = 3
-DATA0 = 4
-DATA1 = 5
-CTX0 = 6
-CTX1 = 7
-IDX0 = 8
-IDX1 = 9
-IDX2 = 10
-IDX3 = 11
-/*
- * param data: r24:r25
- * param ctx: r22:r23
- */
-.global threefish256_dec
-threefish256_dec:
- push r28
- push r29
- push_range 2, 17
- movw DATA0, r24
- movw CTX0, r22
- clr I
- ldi r26, 18
- mov S, r26
-1:
- mov r30, I
- andi r30, 0x03
- breq 2f
- rjmp 4f
-2:
- ldi r30, lo8(threefish256_slut5)
- ldi r31, hi8(threefish256_slut5)
- add r30, S
- adc r31, r1
- lpm IDX0, Z+
- lpm IDX1, Z+
- lpm IDX2, Z+
- lpm IDX3, Z
- movw r30, CTX0
- movw r26, DATA0
- add r30, IDX0
- adc r31, r1
- rcall sub_z_from_x8
- movw r30, CTX0
- add r30, IDX1
- adc r31, r1
- rcall sub_z_from_x8
- movw r30, CTX0
- add r30, IDX2
- adc r31, r1
- rcall sub_z_from_x8
- movw r30, CTX0
- add r30, IDX3
- adc r31, r1
- rcall sub_z_from_x8
-
- /* now the remaining key */
- sbiw r26, 3*8
- ldi r30, lo8(threefish256_slut3)
- ldi r31, hi8(threefish256_slut3)
- add r30, S
- adc r31, r1
- lpm IDX0, Z+
- lpm IDX1, Z
- movw r30, CTX0
- adiw r30, 5*8
- movw IDX2, r30
- add r30, IDX0
- adc r31, r1
- rcall sub_z_from_x8
- movw r30, IDX2
- add r30, IDX1
- adc r31, r1
- rcall sub_z_from_x8
- ld r0, X
- sub r0, S
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- ld r0, X
- sbc r0, r1
- st X+, r0
- tst S
- brne 3f
-exit:
- pop_range 2, 17
- pop r29
- pop r28
- ret
-3:
- dec S
-4:
- /* now the permutation */
- movw r26, DATA0
- adiw r26, 8
- movw r30, r26
- adiw r30, 16
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- ld IDX0, X
- ld IDX1, Z
- st X+, IDX1
- st Z+, IDX0
- /* call mix */
- ldi r30, lo8(threefish256_rc0)
- ldi r31, hi8(threefish256_rc0)
- mov r26, I
- andi r26, 0x07
- add r30, r26
- adc r31, r1
- lpm r22, Z
- adiw r30, 8
- lpm IDX0, Z
- movw r24, DATA0
- call threefish_invmix_asm /* no rcall? */
- movw r24, DATA0
- adiw r24, 16
- mov r22, IDX0
- call threefish_invmix_asm /* no rcall? */
- inc I
- rjmp 1b
-
-threefish256_slut5:
- .byte 0x00, 0x08, 0x10, 0x18, 0x20, 0x00, 0x08, 0x10
- .byte 0x18, 0x20, 0x00, 0x08, 0x10, 0x18, 0x20, 0x00
- .byte 0x08, 0x10, 0x18, 0x20, 0x00, 0x08, 0x10
-threefish256_slut3:
- .byte 0x00, 0x08, 0x10, 0x00, 0x08, 0x10, 0x00, 0x08
- .byte 0x10, 0x00, 0x08, 0x10, 0x00, 0x08, 0x10, 0x00
- .byte 0x08, 0x10, 0x00, 0x08, 0x10, 0x00, 0x08
-
-threefish256_rc0: .byte 0x73, 0x13, 0x7b, 0x32, 0x72, 0x2b, 0x44, 0x1b
-threefish256_rc1: .byte 0x62, 0x52, 0x43, 0x24, 0x54, 0x6a, 0x34, 0x70
-
-sub_z_from_x8:
- ld r0, Z+
- ld r1, X
- sub r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- ld r0, Z+
- ld r1, X
- sbc r1, r0
- st X+, r1
- clr r1
- ret
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