Split off .c file from precomputed_ecmult.h

Author: sipa

.gitattributes

@@ -1,2 +1,2 @@
-src/precomputed_ecmult.h linguist-generated
+src/precomputed_ecmult.c linguist-generated
 src/precomputed_ecmult_gen.c linguist-generated

Makefile.am

@@ -44,6 +44,7 @@ noinst_HEADERS += src/modinv32.h
 noinst_HEADERS += src/modinv32_impl.h
 noinst_HEADERS += src/modinv64.h
 noinst_HEADERS += src/modinv64_impl.h
+noinst_HEADERS += src/precomputed_ecmult.h
 noinst_HEADERS += src/precomputed_ecmult_gen.h
 noinst_HEADERS += src/assumptions.h
 noinst_HEADERS += src/util.h
@@ -65,7 +66,7 @@ noinst_HEADERS += contrib/lax_der_privatekey_parsing.c
 
 PRECOMPUTED_LIB = libsecp256k1_precomputed.la
 noinst_LTLIBRARIES = $(PRECOMPUTED_LIB)
-libsecp256k1_precomputed_la_SOURCES = src/precomputed_ecmult_gen.c
+libsecp256k1_precomputed_la_SOURCES =  src/precomputed_ecmult.c src/precomputed_ecmult_gen.c
 libsecp256k1_precomputed_la_CPPFLAGS = $(SECP_INCLUDES)
 
 if USE_EXTERNAL_ASM
@@ -156,15 +157,14 @@ precompute_ecmult_gen_LDADD = $(SECP_LIBS) $(COMMON_LIB)
 # build by a normal user) depends on mtimes, and thus is very fragile.
 # This means that rebuilds of the prebuilt files always need to be
 # forced by deleting them, e.g., by invoking `make clean-precomp`.
-src/precomputed_ecmult.h:
+src/precomputed_ecmult.c:
 	$(MAKE) $(AM_MAKEFLAGS) precompute_ecmult$(EXEEXT)
 	./precompute_ecmult$(EXEEXT)
 src/precomputed_ecmult_gen.c:
 	$(MAKE) $(AM_MAKEFLAGS) precompute_ecmult_gen$(EXEEXT)
 	./precompute_ecmult_gen$(EXEEXT)
 
-PRECOMP = src/precomputed_ecmult_gen.c
-noinst_HEADERS += src/precomputed_ecmult.h
+PRECOMP = src/precomputed_ecmult_gen.c src/precomputed_ecmult.c
 precomp: $(PRECOMP)
 
 # Ensure the prebuilt files will be build first (only if they don't exist,

configure.ac

@@ -152,7 +152,7 @@ AC_ARG_WITH([ecmult-window], [AS_HELP_STRING([--with-ecmult-window=SIZE|auto],
 [window size for ecmult precomputation for verification, specified as integer in range [2..24].]
 [Larger values result in possibly better performance at the cost of an exponentially larger precomputed table.]
 [The table will store 2^(SIZE-1) * 64 bytes of data but can be larger in memory due to platform-specific padding and alignment.]
-[A window size larger than 15 will require you delete the prebuilt precomputed_ecmult.h file so that it can be rebuilt.]
+[A window size larger than 15 will require you delete the prebuilt precomputed_ecmult.c file so that it can be rebuilt.]
 [For very large window sizes, use "make -j 1" to reduce memory use during compilation.]
 ["auto" is a reasonable setting for desktop machines (currently 15). [default=auto]]
 )],

src/ecmult_impl.h

@@ -103,7 +103,7 @@ static void secp256k1_ecmult_odd_multiples_table(int n, secp256k1_gej *prej, sec
  *  It only operates on tables sized for WINDOW_A wnaf multiples.
  *
  *  To compute a*P + b*G, we compute a table for P using this function,
- *  and use the precomputed table in <precomputed_ecmult.h> for G.
+ *  and use the precomputed table in <precomputed_ecmult.c> for G.
  */
 static void secp256k1_ecmult_odd_multiples_table_globalz_windowa(secp256k1_ge *pre, secp256k1_fe *globalz, const secp256k1_gej *a) {
     secp256k1_gej prej[ECMULT_TABLE_SIZE(WINDOW_A)];

src/precompute_ecmult.c

@@ -25,7 +25,7 @@ static void print_table(FILE *fp, const char *name, int window_g, const secp256k
     int j;
     int i;
 
-    fprintf(fp, "static const secp256k1_ge_storage %s[ECMULT_TABLE_SIZE(WINDOW_G)] = {\n", name);
+    fprintf(fp, "const secp256k1_ge_storage %s[ECMULT_TABLE_SIZE(WINDOW_G)] = {\n", name);
     fprintf(fp, " S(%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32
                   ",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32",%"PRIx32")\n",
                 SECP256K1_GE_STORAGE_CONST_GET(table[0]));
@@ -57,11 +57,9 @@ static void print_two_tables(FILE *fp, int window_g) {
 }
 
 int main(void) {
-    const int window_g_13 = 4;
-    const int window_g_199 = 8;
     FILE* fp;
 
-    fp = fopen("src/precomputed_ecmult.h","w");
+    fp = fopen("src/precomputed_ecmult.c","w");
     if (fp == NULL) {
         fprintf(stderr, "Could not open src/precomputed_ecmult.h for writing!\n");
         return -1;
@@ -71,36 +69,24 @@ int main(void) {
     fprintf(fp, "/* This file contains an array secp256k1_pre_g with odd multiples of the base point G and\n");
     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");
     fprintf(fp, " */\n");
-    fprintf(fp, "#ifndef SECP256K1_PRECOMPUTED_ECMULT_H\n");
-    fprintf(fp, "#define SECP256K1_PRECOMPUTED_ECMULT_H\n");
-    fprintf(fp, "#include \"group.h\"\n");
-    fprintf(fp, "#ifdef S\n");
-    fprintf(fp, "   #error macro identifier S already in use.\n");
+    fprintf(fp, "#if defined HAVE_CONFIG_H\n");
+    fprintf(fp, "#include \"libsecp256k1-config.h\"\n");
     fprintf(fp, "#endif\n");
-    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");
+    fprintf(fp, "#include \"../include/secp256k1.h\"\n");
+    fprintf(fp, "#include \"group.h\"\n");
+    fprintf(fp, "#include \"ecmult.h\"\n");
+    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");
     fprintf(fp, "#if ECMULT_TABLE_SIZE(ECMULT_WINDOW_SIZE) > %ld\n", ECMULT_TABLE_SIZE(ECMULT_WINDOW_SIZE));
-    fprintf(fp, "   #error configuration mismatch, invalid ECMULT_WINDOW_SIZE. Try deleting precomputed_ecmult.h before the build.\n");
-    fprintf(fp, "#endif\n");
-    fprintf(fp, "#if defined(EXHAUSTIVE_TEST_ORDER)\n");
-    fprintf(fp, "#if EXHAUSTIVE_TEST_ORDER == 13\n");
-    fprintf(fp, "#define WINDOW_G %d\n", window_g_13);
-    fprintf(fp, "#elif EXHAUSTIVE_TEST_ORDER == 199\n");
-    fprintf(fp, "#define WINDOW_G %d\n", window_g_199);
-    fprintf(fp, "#else\n");
-    fprintf(fp, "   #error No known generator for the specified exhaustive test group order.\n");
+    fprintf(fp, "   #error configuration mismatch, invalid ECMULT_WINDOW_SIZE. Try deleting precomputed_ecmult.c before the build.\n");
     fprintf(fp, "#endif\n");
-    fprintf(fp, "static secp256k1_ge_storage secp256k1_pre_g[ECMULT_TABLE_SIZE(WINDOW_G)];\n");
-    fprintf(fp, "static secp256k1_ge_storage secp256k1_pre_g_128[ECMULT_TABLE_SIZE(WINDOW_G)];\n");
-    fprintf(fp, "#else /* !defined(EXHAUSTIVE_TEST_ORDER) */\n");
+    fprintf(fp, "#ifdef EXHAUSTIVE_TEST_ORDER\n");
+    fprintf(fp, "#error Cannot compile precomputed_ecmult.c in exhaustive test mode\n");
+    fprintf(fp, "#endif /* EXHAUSTIVE_TEST_ORDER */\n");
     fprintf(fp, "#define WINDOW_G ECMULT_WINDOW_SIZE\n");
 
     print_two_tables(fp, ECMULT_WINDOW_SIZE);
 
-    fprintf(fp, "#endif /* defined(EXHAUSTIVE_TEST_ORDER) */\n");
     fprintf(fp, "#undef S\n");
-    fprintf(fp, "#endif /* SECP256K1_PRECOMPUTED_ECMULT_H */\n");
     fclose(fp);
 
     return 0;