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
29 static inline void
bn_subw(BN_ULONG a,BN_ULONG b,BN_ULONG * out_borrow,BN_ULONG * out_r0)30 bn_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
49 static inline void
bn_subw_subw(BN_ULONG a,BN_ULONG b,BN_ULONG c,BN_ULONG * out_borrow,BN_ULONG * out_r0)50 bn_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