1/*	$OpenBSD: bn_arch.h,v 1.2 2023/06/24 15:51:47 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_SUBW
28
29static inline void
30bn_subw(BN_ULONG a, BN_ULONG b, BN_ULONG *out_borrow, BN_ULONG *out_r0)
31{
32	BN_ULONG borrow, r0;
33
34	__asm__ (
35	    "mov  %[borrow], #0 \n"
36	    "subs %[r0], %[a], %[b] \n"
37	    "sbc  %[borrow], %[borrow], #0 \n"
38	    "neg  %[borrow], %[borrow] \n"
39	    : [borrow]"=&r"(borrow), [r0]"=r"(r0)
40	    : [a]"r"(a), [b]"r"(b)
41	    : "cc");
42
43	*out_borrow = borrow;
44	*out_r0 = r0;
45}
46
47#define HAVE_BN_SUBW_SUBW
48
49static inline void
50bn_subw_subw(BN_ULONG a, BN_ULONG b, BN_ULONG c, BN_ULONG *out_borrow,
51    BN_ULONG *out_r0)
52{
53	BN_ULONG borrow, r0;
54
55	__asm__ (
56	    "mov  %[borrow], #0 \n"
57	    "subs %[r0], %[a], %[b] \n"
58	    "sbc  %[borrow], %[borrow], #0 \n"
59	    "subs %[r0], %[r0], %[c] \n"
60	    "sbc  %[borrow], %[borrow], #0 \n"
61	    "neg  %[borrow], %[borrow] \n"
62	    : [borrow]"=&r"(borrow), [r0]"=&r"(r0)
63	    : [a]"r"(a), [b]"r"(b), [c]"r"(c)
64	    : "cc");
65
66	*out_borrow = borrow;
67	*out_r0 = r0;
68}
69
70#endif /* __GNUC__ */
71
72#endif
73#endif
74