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
29 static inline void
bn_addw(BN_ULONG a,BN_ULONG b,BN_ULONG * out_r1,BN_ULONG * out_r0)30 bn_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
46 static inline void
bn_mulw(BN_ULONG a,BN_ULONG b,BN_ULONG * out_r1,BN_ULONG * out_r0)47 bn_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
68 static inline void
bn_subw(BN_ULONG a,BN_ULONG b,BN_ULONG * out_borrow,BN_ULONG * out_r0)69 bn_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