1/* $OpenBSD: bn_arch.h,v 1.7 2023/07/09 10:37:32 jsing Exp $ */ 2/* 3 * Copyright (c) 2023 Joel Sing <jsing@openbsd.org> 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18#include <openssl/bn.h> 19 20#ifndef HEADER_BN_ARCH_H 21#define HEADER_BN_ARCH_H 22 23#ifndef OPENSSL_NO_ASM 24 25#if defined(__GNUC__) 26 27#define HAVE_BN_ADDW 28 29static inline void 30bn_addw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_r1, BN_ULONG *out_r0) 31{ 32 BN_ULONG carry, r0; 33 34 __asm__ ( 35 "add %[r0], %[a], %[b] \n" 36 "sltu %[carry], %[r0], %[a] \n" 37 : [carry]"=r"(carry), [r0]"=&r"(r0) 38 : [a]"r"(a), [b]"r"(b)); 39 40 *out_r1 = carry; 41 *out_r0 = r0; 42} 43 44#define HAVE_BN_MULW 45 46static inline void 47bn_mulw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_r1, BN_ULONG *out_r0) 48{ 49 BN_ULONG r1, r0; 50 51 /* 52 * Unsigned multiplication using a mulh/mul pair. Note that the order 53 * of these instructions is important, as they can potentially be fused 54 * into a single operation. 55 */ 56 __asm__ ( 57 "mulhu %[r1], %[a], %[b] \n" 58 "mul %[r0], %[a], %[b] \n" 59 : [r1]"=&r"(r1), [r0]"=r"(r0) 60 : [a]"r"(a), [b]"r"(b)); 61 62 *out_r1 = r1; 63 *out_r0 = r0; 64} 65 66#define HAVE_BN_SUBW 67 68static inline void 69bn_subw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_borrow, BN_ULONG *out_r0) 70{ 71 BN_ULONG borrow, r0; 72 73 __asm__ ( 74 "sub %[r0], %[a], %[b] \n" 75 "sltu %[borrow], %[a], %[r0] \n" 76 : [borrow]"=r"(borrow), [r0]"=&r"(r0) 77 : [a]"r"(a), [b]"r"(b)); 78 79 *out_borrow = borrow; 80 *out_r0 = r0; 81} 82 83#endif /* __GNUC__ */ 84 85#endif 86#endif 87