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/* twofish-aarch64.S - ARMv8/AArch64 assembly implementation of Twofish cipher
*
* Copyright (C) 2016 Jussi Kivilinna <jussi.kivilinna@iki.fi>
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
*/
#include "asm-common-aarch64.h"
#if defined(__AARCH64EL__)
#ifdef HAVE_COMPATIBLE_GCC_AARCH64_PLATFORM_AS
.text
/* structure of TWOFISH_context: */
#define s0 0
#define s1 ((s0) + 4 * 256)
#define s2 ((s1) + 4 * 256)
#define s3 ((s2) + 4 * 256)
#define w ((s3) + 4 * 256)
#define k ((w) + 4 * 8)
/* register macros */
#define CTX x0
#define RDST x1
#define RSRC x2
#define CTXs0 CTX
#define CTXs1 x3
#define CTXs2 x4
#define CTXs3 x5
#define CTXw x17
#define RA w6
#define RB w7
#define RC w8
#define RD w9
#define RX w10
#define RY w11
#define xRX x10
#define xRY x11
#define RMASK w12
#define RT0 w13
#define RT1 w14
#define RT2 w15
#define RT3 w16
#define xRT0 x13
#define xRT1 x14
#define xRT2 x15
#define xRT3 x16
/* helper macros */
#ifndef __AARCH64EL__
/* bswap on big-endian */
#define host_to_le(reg) \
rev reg, reg;
#define le_to_host(reg) \
rev reg, reg;
#else
/* nop on little-endian */
#define host_to_le(reg) /*_*/
#define le_to_host(reg) /*_*/
#endif
#define ldr_input_aligned_le(rin, a, b, c, d) \
ldr a, [rin, #0]; \
ldr b, [rin, #4]; \
le_to_host(a); \
ldr c, [rin, #8]; \
le_to_host(b); \
ldr d, [rin, #12]; \
le_to_host(c); \
le_to_host(d);
#define str_output_aligned_le(rout, a, b, c, d) \
le_to_host(a); \
le_to_host(b); \
str a, [rout, #0]; \
le_to_host(c); \
str b, [rout, #4]; \
le_to_host(d); \
str c, [rout, #8]; \
str d, [rout, #12];
/* unaligned word reads/writes allowed */
#define ldr_input_le(rin, ra, rb, rc, rd, rtmp) \
ldr_input_aligned_le(rin, ra, rb, rc, rd)
#define str_output_le(rout, ra, rb, rc, rd, rtmp0, rtmp1) \
str_output_aligned_le(rout, ra, rb, rc, rd)
/**********************************************************************
1-way twofish
**********************************************************************/
#define encrypt_round(a, b, rc, rd, n, ror_a, adj_a) \
and RT0, RMASK, b, lsr#(8 - 2); \
and RY, RMASK, b, lsr#(16 - 2); \
and RT1, RMASK, b, lsr#(24 - 2); \
ldr RY, [CTXs3, xRY]; \
and RT2, RMASK, b, lsl#(2); \
ldr RT0, [CTXs2, xRT0]; \
and RT3, RMASK, a, lsr#(16 - 2 + (adj_a)); \
ldr RT1, [CTXs0, xRT1]; \
and RX, RMASK, a, lsr#(8 - 2 + (adj_a)); \
ldr RT2, [CTXs1, xRT2]; \
ldr RX, [CTXs1, xRX]; \
ror_a(a); \
\
eor RY, RY, RT0; \
ldr RT3, [CTXs2, xRT3]; \
and RT0, RMASK, a, lsl#(2); \
eor RY, RY, RT1; \
and RT1, RMASK, a, lsr#(24 - 2); \
eor RY, RY, RT2; \
ldr RT0, [CTXs0, xRT0]; \
eor RX, RX, RT3; \
ldr RT1, [CTXs3, xRT1]; \
eor RX, RX, RT0; \
\
ldr RT3, [CTXs3, #(k - s3 + 8 * (n) + 4)]; \
eor RX, RX, RT1; \
ldr RT2, [CTXs3, #(k - s3 + 8 * (n))]; \
\
add RT0, RX, RY, lsl #1; \
add RX, RX, RY; \
add RT0, RT0, RT3; \
add RX, RX, RT2; \
eor rd, RT0, rd, ror #31; \
eor rc, rc, RX;
#define dummy(x) /*_*/
#define ror1(r) \
ror r, r, #1;
#define decrypt_round(a, b, rc, rd, n, ror_b, adj_b) \
and RT3, RMASK, b, lsl#(2 - (adj_b)); \
and RT1, RMASK, b, lsr#(8 - 2 + (adj_b)); \
ror_b(b); \
and RT2, RMASK, a, lsl#(2); \
and RT0, RMASK, a, lsr#(8 - 2); \
\
ldr RY, [CTXs1, xRT3]; \
ldr RX, [CTXs0, xRT2]; \
and RT3, RMASK, b, lsr#(16 - 2); \
ldr RT1, [CTXs2, xRT1]; \
and RT2, RMASK, a, lsr#(16 - 2); \
ldr RT0, [CTXs1, xRT0]; \
\
ldr RT3, [CTXs3, xRT3]; \
eor RY, RY, RT1; \
\
and RT1, RMASK, b, lsr#(24 - 2); \
eor RX, RX, RT0; \
ldr RT2, [CTXs2, xRT2]; \
and RT0, RMASK, a, lsr#(24 - 2); \
\
ldr RT1, [CTXs0, xRT1]; \
\
eor RY, RY, RT3; \
ldr RT0, [CTXs3, xRT0]; \
eor RX, RX, RT2; \
eor RY, RY, RT1; \
\
ldr RT1, [CTXs3, #(k - s3 + 8 * (n) + 4)]; \
eor RX, RX, RT0; \
ldr RT2, [CTXs3, #(k - s3 + 8 * (n))]; \
\
add RT0, RX, RY, lsl #1; \
add RX, RX, RY; \
add RT0, RT0, RT1; \
add RX, RX, RT2; \
eor rd, rd, RT0; \
eor rc, RX, rc, ror #31;
#define first_encrypt_cycle(nc) \
encrypt_round(RA, RB, RC, RD, (nc) * 2, dummy, 0); \
encrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, ror1, 1);
#define encrypt_cycle(nc) \
encrypt_round(RA, RB, RC, RD, (nc) * 2, ror1, 1); \
encrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, ror1, 1);
#define last_encrypt_cycle(nc) \
encrypt_round(RA, RB, RC, RD, (nc) * 2, ror1, 1); \
encrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, ror1, 1); \
ror1(RA);
#define first_decrypt_cycle(nc) \
decrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, dummy, 0); \
decrypt_round(RA, RB, RC, RD, (nc) * 2, ror1, 1);
#define decrypt_cycle(nc) \
decrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, ror1, 1); \
decrypt_round(RA, RB, RC, RD, (nc) * 2, ror1, 1);
#define last_decrypt_cycle(nc) \
decrypt_round(RC, RD, RA, RB, (nc) * 2 + 1, ror1, 1); \
decrypt_round(RA, RB, RC, RD, (nc) * 2, ror1, 1); \
ror1(RD);
.globl _gcry_twofish_arm_encrypt_block
ELF(.type _gcry_twofish_arm_encrypt_block,%function;)
_gcry_twofish_arm_encrypt_block:
/* input:
* x0: ctx
* x1: dst
* x2: src
*/
CFI_STARTPROC();
add CTXw, CTX, #(w);
ldr_input_le(RSRC, RA, RB, RC, RD, RT0);
/* Input whitening */
ldp RT0, RT1, [CTXw, #(0*8)];
ldp RT2, RT3, [CTXw, #(1*8)];
add CTXs3, CTX, #(s3);
add CTXs2, CTX, #(s2);
add CTXs1, CTX, #(s1);
mov RMASK, #(0xff << 2);
eor RA, RA, RT0;
eor RB, RB, RT1;
eor RC, RC, RT2;
eor RD, RD, RT3;
first_encrypt_cycle(0);
encrypt_cycle(1);
encrypt_cycle(2);
encrypt_cycle(3);
encrypt_cycle(4);
encrypt_cycle(5);
encrypt_cycle(6);
last_encrypt_cycle(7);
/* Output whitening */
ldp RT0, RT1, [CTXw, #(2*8)];
ldp RT2, RT3, [CTXw, #(3*8)];
eor RC, RC, RT0;
eor RD, RD, RT1;
eor RA, RA, RT2;
eor RB, RB, RT3;
str_output_le(RDST, RC, RD, RA, RB, RT0, RT1);
ret;
CFI_ENDPROC();
.ltorg
ELF(.size _gcry_twofish_arm_encrypt_block,.-_gcry_twofish_arm_encrypt_block;)
.globl _gcry_twofish_arm_decrypt_block
ELF(.type _gcry_twofish_arm_decrypt_block,%function;)
_gcry_twofish_arm_decrypt_block:
/* input:
* %r0: ctx
* %r1: dst
* %r2: src
*/
CFI_STARTPROC();
add CTXw, CTX, #(w);
ldr_input_le(RSRC, RC, RD, RA, RB, RT0);
/* Input whitening */
ldp RT0, RT1, [CTXw, #(2*8)];
ldp RT2, RT3, [CTXw, #(3*8)];
add CTXs3, CTX, #(s3);
add CTXs2, CTX, #(s2);
add CTXs1, CTX, #(s1);
mov RMASK, #(0xff << 2);
eor RC, RC, RT0;
eor RD, RD, RT1;
eor RA, RA, RT2;
eor RB, RB, RT3;
first_decrypt_cycle(7);
decrypt_cycle(6);
decrypt_cycle(5);
decrypt_cycle(4);
decrypt_cycle(3);
decrypt_cycle(2);
decrypt_cycle(1);
last_decrypt_cycle(0);
/* Output whitening */
ldp RT0, RT1, [CTXw, #(0*8)];
ldp RT2, RT3, [CTXw, #(1*8)];
eor RA, RA, RT0;
eor RB, RB, RT1;
eor RC, RC, RT2;
eor RD, RD, RT3;
str_output_le(RDST, RA, RB, RC, RD, RT0, RT1);
ret;
CFI_ENDPROC();
ELF(.size _gcry_twofish_arm_decrypt_block,.-_gcry_twofish_arm_decrypt_block;)
#endif /*HAVE_COMPATIBLE_GCC_AARCH64_PLATFORM_AS*/
#endif /*__AARCH64EL__*/