1 /* SPDX-License-Identifier: GPL-2.0-or-later * 1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* mpi-inline.h - Internal to the Multi Prec 2 /* mpi-inline.h - Internal to the Multi Precision Integers
3 * Copyright (C) 1994, 1996, 1998, 1999 F 3 * Copyright (C) 1994, 1996, 1998, 1999 Free Software Foundation, Inc.
4 * 4 *
5 * This file is part of GnuPG. 5 * This file is part of GnuPG.
6 * 6 *
7 * Note: This code is heavily based on the GNU 7 * Note: This code is heavily based on the GNU MP Library.
8 * Actually it's the same code with only 8 * Actually it's the same code with only minor changes in the
9 * way the data is stored; this is to su 9 * way the data is stored; this is to support the abstraction
10 * of an optional secure memory allocati 10 * of an optional secure memory allocation which may be used
11 * to avoid revealing of sensitive data 11 * to avoid revealing of sensitive data due to paging etc.
12 * The GNU MP Library itself is publishe 12 * The GNU MP Library itself is published under the LGPL;
13 * however I decided to publish this cod 13 * however I decided to publish this code under the plain GPL.
14 */ 14 */
15 15
16 #ifndef G10_MPI_INLINE_H 16 #ifndef G10_MPI_INLINE_H
17 #define G10_MPI_INLINE_H 17 #define G10_MPI_INLINE_H
18 18
19 #ifndef G10_MPI_INLINE_DECL 19 #ifndef G10_MPI_INLINE_DECL
20 #define G10_MPI_INLINE_DECL static inline 20 #define G10_MPI_INLINE_DECL static inline
21 #endif 21 #endif
22 22
23 G10_MPI_INLINE_DECL mpi_limb_t 23 G10_MPI_INLINE_DECL mpi_limb_t
24 mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ 24 mpihelp_add_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
25 mpi_size_t s1_size, mpi_limb_t s 25 mpi_size_t s1_size, mpi_limb_t s2_limb)
26 { 26 {
27 mpi_limb_t x; 27 mpi_limb_t x;
28 28
29 x = *s1_ptr++; 29 x = *s1_ptr++;
30 s2_limb += x; 30 s2_limb += x;
31 *res_ptr++ = s2_limb; 31 *res_ptr++ = s2_limb;
32 if (s2_limb < x) { /* sum is less 32 if (s2_limb < x) { /* sum is less than the left operand: handle carry */
33 while (--s1_size) { 33 while (--s1_size) {
34 x = *s1_ptr++ + 1; 34 x = *s1_ptr++ + 1; /* add carry */
35 *res_ptr++ = x; /* and 35 *res_ptr++ = x; /* and store */
36 if (x) /* not 0 (no o 36 if (x) /* not 0 (no overflow): we can stop */
37 goto leave; 37 goto leave;
38 } 38 }
39 return 1; /* return carr 39 return 1; /* return carry (size of s1 to small) */
40 } 40 }
41 41
42 leave: 42 leave:
43 if (res_ptr != s1_ptr) { /* not 43 if (res_ptr != s1_ptr) { /* not the same variable */
44 mpi_size_t i; /* copy the re 44 mpi_size_t i; /* copy the rest */
45 for (i = 0; i < s1_size - 1; i 45 for (i = 0; i < s1_size - 1; i++)
46 res_ptr[i] = s1_ptr[i] 46 res_ptr[i] = s1_ptr[i];
47 } 47 }
48 return 0; /* no carry */ 48 return 0; /* no carry */
49 } 49 }
50 50
51 G10_MPI_INLINE_DECL mpi_limb_t 51 G10_MPI_INLINE_DECL mpi_limb_t
52 mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_pt 52 mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
53 mpi_ptr_t s2_ptr, mpi_size_t s2_si 53 mpi_ptr_t s2_ptr, mpi_size_t s2_size)
54 { 54 {
55 mpi_limb_t cy = 0; 55 mpi_limb_t cy = 0;
56 56
57 if (s2_size) 57 if (s2_size)
58 cy = mpihelp_add_n(res_ptr, s1 58 cy = mpihelp_add_n(res_ptr, s1_ptr, s2_ptr, s2_size);
59 59
60 if (s1_size - s2_size) 60 if (s1_size - s2_size)
61 cy = mpihelp_add_1(res_ptr + s 61 cy = mpihelp_add_1(res_ptr + s2_size, s1_ptr + s2_size,
62 s1_size - s 62 s1_size - s2_size, cy);
63 return cy; 63 return cy;
64 } 64 }
65 65
66 G10_MPI_INLINE_DECL mpi_limb_t 66 G10_MPI_INLINE_DECL mpi_limb_t
67 mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ 67 mpihelp_sub_1(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
68 mpi_size_t s1_size, mpi_limb_t s 68 mpi_size_t s1_size, mpi_limb_t s2_limb)
69 { 69 {
70 mpi_limb_t x; 70 mpi_limb_t x;
71 71
72 x = *s1_ptr++; 72 x = *s1_ptr++;
73 s2_limb = x - s2_limb; 73 s2_limb = x - s2_limb;
74 *res_ptr++ = s2_limb; 74 *res_ptr++ = s2_limb;
75 if (s2_limb > x) { 75 if (s2_limb > x) {
76 while (--s1_size) { 76 while (--s1_size) {
77 x = *s1_ptr++; 77 x = *s1_ptr++;
78 *res_ptr++ = x - 1; 78 *res_ptr++ = x - 1;
79 if (x) 79 if (x)
80 goto leave; 80 goto leave;
81 } 81 }
82 return 1; 82 return 1;
83 } 83 }
84 84
85 leave: 85 leave:
86 if (res_ptr != s1_ptr) { 86 if (res_ptr != s1_ptr) {
87 mpi_size_t i; 87 mpi_size_t i;
88 for (i = 0; i < s1_size - 1; i 88 for (i = 0; i < s1_size - 1; i++)
89 res_ptr[i] = s1_ptr[i] 89 res_ptr[i] = s1_ptr[i];
90 } 90 }
91 return 0; 91 return 0;
92 } 92 }
93 93
94 G10_MPI_INLINE_DECL mpi_limb_t 94 G10_MPI_INLINE_DECL mpi_limb_t
95 mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_pt 95 mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr, mpi_size_t s1_size,
96 mpi_ptr_t s2_ptr, mpi_size_t s2_si 96 mpi_ptr_t s2_ptr, mpi_size_t s2_size)
97 { 97 {
98 mpi_limb_t cy = 0; 98 mpi_limb_t cy = 0;
99 99
100 if (s2_size) 100 if (s2_size)
101 cy = mpihelp_sub_n(res_ptr, s1 101 cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);
102 102
103 if (s1_size - s2_size) 103 if (s1_size - s2_size)
104 cy = mpihelp_sub_1(res_ptr + s 104 cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
105 s1_size - s 105 s1_size - s2_size, cy);
106 return cy; 106 return cy;
107 } 107 }
108 108
109 #endif /*G10_MPI_INLINE_H */ 109 #endif /*G10_MPI_INLINE_H */
110 110
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