Bitcoin Core  24.99.0
P2P Digital Currency
precompute_ecmult.c
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1 /*****************************************************************************************************
2  * Copyright (c) 2013, 2014, 2017, 2021 Pieter Wuille, Andrew Poelstra, Jonas Nick, Russell O'Connor *
3  * Distributed under the MIT software license, see the accompanying *
4  * file COPYING or https://www.opensource.org/licenses/mit-license.php. *
5  *****************************************************************************************************/
6 
7 #include <inttypes.h>
8 #include <stdio.h>
9 
10 /* Autotools creates libsecp256k1-config.h, of which ECMULT_WINDOW_SIZE is needed.
11  ifndef guard so downstream users can define their own if they do not use autotools. */
12 #if !defined(ECMULT_WINDOW_SIZE)
13 #include "libsecp256k1-config.h"
14 #endif
15 
16 #include "../include/secp256k1.h"
17 #include "assumptions.h"
18 #include "util.h"
19 #include "field_impl.h"
20 #include "group_impl.h"
21 #include "ecmult.h"
23 
24 static void print_table(FILE *fp, const char *name, int window_g, const secp256k1_ge_storage* table) {
25  int j;
26  int i;
27 
28  fprintf(fp, "const secp256k1_ge_storage %s[ECMULT_TABLE_SIZE(WINDOW_G)] = {\n", name);
29  fprintf(fp, " S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
30  ",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")\n",
32 
33  j = 1;
34  for(i = 3; i <= window_g; ++i) {
35  fprintf(fp, "#if WINDOW_G > %d\n", i-1);
36  for(;j < ECMULT_TABLE_SIZE(i); ++j) {
37  fprintf(fp, ",S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
38  ",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")\n",
40  }
41  fprintf(fp, "#endif\n");
42  }
43  fprintf(fp, "};\n");
44 }
45 
46 static void print_two_tables(FILE *fp, int window_g) {
47  secp256k1_ge_storage* table = malloc(ECMULT_TABLE_SIZE(window_g) * sizeof(secp256k1_ge_storage));
48  secp256k1_ge_storage* table_128 = malloc(ECMULT_TABLE_SIZE(window_g) * sizeof(secp256k1_ge_storage));
49 
50  secp256k1_ecmult_compute_two_tables(table, table_128, window_g, &secp256k1_ge_const_g);
51 
52  print_table(fp, "secp256k1_pre_g", window_g, table);
53  print_table(fp, "secp256k1_pre_g_128", window_g, table_128);
54 
55  free(table);
56  free(table_128);
57 }
58 
59 int main(void) {
60  /* Always compute all tables for window sizes up to 15. */
61  int window_g = (ECMULT_WINDOW_SIZE < 15) ? 15 : ECMULT_WINDOW_SIZE;
62  FILE* fp;
63 
64  fp = fopen("src/precomputed_ecmult.c","w");
65  if (fp == NULL) {
66  fprintf(stderr, "Could not open src/precomputed_ecmult.h for writing!\n");
67  return -1;
68  }
69 
70  fprintf(fp, "/* This file was automatically generated by precompute_ecmult. */\n");
71  fprintf(fp, "/* This file contains an array secp256k1_pre_g with odd multiples of the base point G and\n");
72  fprintf(fp, " * an array secp256k1_pre_g_128 with odd multiples of 2^128*G for accelerating the computation of a*P + b*G.\n");
73  fprintf(fp, " */\n");
74  fprintf(fp, "#if defined HAVE_CONFIG_H\n");
75  fprintf(fp, "# include \"libsecp256k1-config.h\"\n");
76  fprintf(fp, "#endif\n");
77  fprintf(fp, "#include \"../include/secp256k1.h\"\n");
78  fprintf(fp, "#include \"group.h\"\n");
79  fprintf(fp, "#include \"ecmult.h\"\n");
80  fprintf(fp, "#include \"precomputed_ecmult.h\"\n");
81  fprintf(fp, "#define S(a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p) SECP256K1_GE_STORAGE_CONST(0x##a##u,0x##b##u,0x##c##u,0x##d##u,0x##e##u,0x##f##u,0x##g##u,0x##h##u,0x##i##u,0x##j##u,0x##k##u,0x##l##u,0x##m##u,0x##n##u,0x##o##u,0x##p##u)\n");
82  fprintf(fp, "#if ECMULT_WINDOW_SIZE > %d\n", window_g);
83  fprintf(fp, " #error configuration mismatch, invalid ECMULT_WINDOW_SIZE. Try deleting precomputed_ecmult.c before the build.\n");
84  fprintf(fp, "#endif\n");
85  fprintf(fp, "#ifdef EXHAUSTIVE_TEST_ORDER\n");
86  fprintf(fp, "# error Cannot compile precomputed_ecmult.c in exhaustive test mode\n");
87  fprintf(fp, "#endif /* EXHAUSTIVE_TEST_ORDER */\n");
88  fprintf(fp, "#define WINDOW_G ECMULT_WINDOW_SIZE\n");
89 
90  print_two_tables(fp, window_g);
91 
92  fprintf(fp, "#undef S\n");
93  fclose(fp);
94 
95  return 0;
96 }
#define ECMULT_TABLE_SIZE(w)
The number of entries a table with precomputed multiples needs to have.
Definition: ecmult.h:30
static void secp256k1_ecmult_compute_two_tables(secp256k1_ge_storage *table, secp256k1_ge_storage *table_128, int window_g, const secp256k1_ge *gen)
#define SECP256K1_GE_STORAGE_CONST_GET(t)
Definition: group.h:45
static const secp256k1_ge secp256k1_ge_const_g
Definition: group_impl.h:62
#define ECMULT_WINDOW_SIZE
FILE * fopen(const fs::path &p, const char *mode)
Definition: fs.cpp:25
static void print_two_tables(FILE *fp, int window_g)
int main(void)
static void print_table(FILE *fp, const char *name, int window_g, const secp256k1_ge_storage *table)
const char * name
Definition: rest.cpp:46