Minor

src/include/barrett_field.h:

- Requires review: corrected failure to cast to (mask_t) prior to negation. (Or, if this is wrong; should cast to needed bitwidth explicitly.)
- Changed type of nwords_out to uint32_t to agree with header.

src/include/intrinsics.h:

- Fixed up various preprocessor statements to check for definition rather than value of built-ins.
- Added macro to use Clang’s __builtin_readcyclecounter on platforms on which it’s available. (Which is most platforms these days.)

src/include/magic.h: Preprocessor “if” versus “if defined”.

src/include/word.h: Fixed ifdefs; enabled support for memset_s on Darwin. Added explicit cast to mask_t.

Added void to function definitions and declarations in the following files (not including void is okay in modern C++, but not modern C, IIRC):

include/goldilocks.h, src/crandom.c, src/goldilocks.c, src/include/api.h, src/include/intrinsics.h, test/bench.c, test/test.c, test/test.h, test/test_arithmetic.c, test/test_goldilocks.c, test/test_pointops.c, test/test_scalarmul.c, test/test_sha512.c

include/goldilocks.h

@@ -100,7 +100,7 @@ static const int GOLDI_EALREADYINIT  = 44805;
  * @retval Nonzero An error occurred.
  */
 int
-goldilocks_init ()
+goldilocks_init (void)
 __attribute__((warn_unused_result,visibility ("default")));
 
 

src/crandom.c

@@ -14,7 +14,7 @@
 
 volatile unsigned int crandom_features = 0;
 
-unsigned int crandom_detect_features() {
+unsigned int crandom_detect_features(void) {
   unsigned int out = GEN;
   
 # if (defined(__i386__) || defined(__x86_64__))

src/goldilocks.c

@@ -57,7 +57,7 @@ static struct {
 } goldilocks_global;
 
 static inline mask_t
-goldilocks_check_init() {
+goldilocks_check_init(void) {
     if (likely(goldilocks_global.state == G_INITED)) {
         return MASK_SUCCESS;
     } else {
@@ -66,7 +66,7 @@ goldilocks_check_init() {
 }
 
 int
-goldilocks_init () {
+goldilocks_init (void) {
     const char *res = compare_and_swap(&goldilocks_global.state, NULL, G_INITING);
     if (res == G_INITED) return GOLDI_EALREADYINIT;
     else if (res) {

src/include/api.h

@@ -43,9 +43,9 @@
 #endif
 */
 
-static inline int timingattacks() { return 0; }
-static inline int copyrightclaims() { return 0; }
-static inline int patentclaims() {
+static inline int timingattacks(void) { return 0; }
+static inline int copyrightclaims(void) { return 0; }
+static inline int patentclaims(void) {
     /* Until the end of July 2014, point compression
      * is patented. */
     return 20;

src/include/barrett_field.h

@@ -37,7 +37,7 @@ extern const struct barrett_prime_t curve_prime_order;
 /**
  * Reduce a number (with optional high carry word) mod p.
  *
- * @param [inout] a The value to be reduced.
+ * @param [in,out] a The value to be reduced.
  * @param [in] nwords_a The number of words in a.
  * @param [in] a_carry A high word to be carried into the computation.
  * @param [in] prime The Barrett prime.
@@ -132,7 +132,7 @@ barrett_mul_or_mac(
 static inline void
 barrett_mul(
     word_t *out,
-    int nwords_out,
+    uint32_t nwords_out,
 
     const word_t *a,
     uint32_t nwords_a,
@@ -158,7 +158,7 @@ barrett_mac(
 
     const struct barrett_prime_t *prime
 ) {
-    barrett_mul_or_mac(out,nwords_out,a,nwords_a,b,nwords_b,prime,-1);
+    barrett_mul_or_mac(out,nwords_out,a,nwords_a,b,nwords_b,prime,-(mask_t)1);
 }
 
 mask_t

src/include/intrinsics.h

@@ -13,13 +13,13 @@
 #include <sys/types.h>
 #include "config.h"
 
-#if __i386__ || __x86_64__
+#if defined(__i386__) || defined(__x86_64__)
 #include <immintrin.h>
 #endif
 
 /** @brief Macro to make a function static, forcibly inlined and possibly unused. */
 #define INTRINSIC \
-  static __inline__ __attribute__((__gnu_inline__, __always_inline__, unused))
+  static inline __attribute__((__gnu_inline__, __always_inline__))
 
 #define GEN    1     /**< @brief Intrinsics field has been generated. */
 #define SSE2   2     /**< @brief Machine supports SSE2 */
@@ -33,13 +33,20 @@
 /**
  * @brief If on x86, read the timestamp counter.  Otherwise, return 0.
  */
-INTRINSIC u_int64_t rdtsc() {
+#ifndef __has_builtin
+#define __has_builtin(X) 0
+#endif
+#if defined(__clang__) && __has_builtin(__builtin_readcyclecounter)
+#define rdtsc __builtin_readcyclecounter
+#else
+INTRINSIC u_int64_t rdtsc(void) {
   u_int64_t out = 0;
 # if (defined(__i386__) || defined(__x86_64__))
     __asm__ __volatile__ ("rdtsc" : "=A"(out));
 # endif
   return out;
 }
+#endif
 
 /**
  * Return x unchanged, but confuse the compiler.

src/include/magic.h

@@ -76,7 +76,7 @@ extern const word_t SCALARMUL_FIXED_WINDOW_ADJUSTMENT[2*SCALAR_WORDS];
  * @brief If true, use wider tables for the precomputed combs.
  */
 #ifndef USE_BIG_COMBS
-#if __ARM_NEON__
+#if defined(__ARM_NEON__)
 #define USE_BIG_COMBS 1
 #else
 #define USE_BIG_COMBS (WORD_BITS==64)

src/include/word.h

@@ -20,13 +20,16 @@
 #include <sys/types.h>
 #include <inttypes.h>
 
-#if __ARM_NEON__
+#if defined(__ARM_NEON__)
 #include <arm_neon.h>
-#elif __SSE2__
+#elif defined(__SSE2__)
 #include <immintrin.h>
 #endif
 
-#if (__SIZEOF_INT128__ == 16 && __SIZEOF_SIZE_T__ == 8 && (__SIZEOF_LONG__==8 || __POINTER_WIDTH__==64) && !GOLDI_FORCE_32_BIT)
+#if (__SIZEOF_INT128__ == 16 \
+        && __SIZEOF_SIZE_T__ == 8 \
+        && (__SIZEOF_LONG__==8 || __POINTER_WIDTH__==64) \
+        && !defined(GOLDI_FORCE_32_BIT))
 /* It's a 64-bit machine if:
  * __uint128_t exists
  * size_t is 64 bits
@@ -67,7 +70,7 @@ typedef int64_t dsword_t;
 #define WORDS_FOR_BITS(_x) (DIV_CEIL((_x),WORD_BITS))
 
 typedef word_t mask_t;
-static const mask_t MASK_FAILURE = 0, MASK_SUCCESS = -1;
+static const mask_t MASK_FAILURE = 0, MASK_SUCCESS = -(mask_t)1;
 
 
 
@@ -106,7 +109,7 @@ typedef word_t vecmask_t __attribute__((vector_size(32)));
 
     static __inline__ big_register_t
     br_set_to_mask(mask_t x) {
-        uint32_t y = x;
+        uint32_t y = (uint32_t)x;
         big_register_t ret = {y,y,y,y,y,y,y,y};
         return ret;
     }
@@ -193,10 +196,22 @@ letoh64 (uint64_t x) { return x; }
  * @param c The char to set it to (probably zero).
  * @param s The size of the object.
  */
-#ifdef __STDC_LIB_EXT1__ /* which it won't be, because we're -std=c99 */
+#if (defined(__DARWIN_C_LEVEL) \
+    || (defined(__STDC_WANT_LIB_EXT1__) && __STDC_WANT_LIB_EXT1__ == 1))
+#define HAS_MEMSET_S
+#endif
+
+#if !defined(__STDC_WANT_LIB_EXT1__) || __STDC_WANT_LIB_EXT1__ != 1
+#define NEED_MEMSET_S_EXTERN
+#endif
+
+#ifdef HAS_MEMSET_S
+#ifdef NEED_MEMSET_S_EXTERN
+extern int memset_s(void *, size_t, int, size_t);
+#endif
 static __inline__ void
 really_memset(void *p, char c, size_t s) {
-    memset_s(p,s,c,s);
+    memset_s(p, s, c, s);
 }
 #else
 static __inline__ void __attribute__((always_inline,unused))

test/bench.c

@@ -22,7 +22,7 @@ ignore_result ( int result ) {
     (void)result;
 }
 
-static double now() {
+static double now(void) {
   struct timeval tv;
   gettimeofday(&tv, NULL);
   

test/test.c

@@ -9,7 +9,7 @@
 
 int failed_tests, n_tests, failed_this_test, running_a_test;
 
-static void end_test() {
+static void end_test(void) {
     if (!failed_this_test) {
         printf("[PASS]\n");
     }
@@ -25,7 +25,7 @@ static void begin_test(const char *name) {
     running_a_test = 1;
 }
 
-void youfail() {
+void youfail(void) {
     if (failed_this_test) return;
     failed_this_test = 1;
     failed_tests ++;

test/test.h

@@ -29,20 +29,20 @@ void scalar_print (
     int nwords
 );
 
-void youfail();
+void youfail(void);
 
-int test_sha512_monte_carlo();
+int test_sha512_monte_carlo(void);
 
-int test_linear_combo ();
+int test_linear_combo (void);
 
-int test_scalarmul_compatibility ();
+int test_scalarmul_compatibility (void);
 
-int test_scalarmul_commutativity ();
+int test_scalarmul_commutativity (void);
 
-int test_arithmetic ();
+int test_arithmetic (void);
 
-int test_goldilocks ();
+int test_goldilocks (void);
 
-int test_pointops ();
+int test_pointops (void);
 
 #endif // __GOLDILOCKS_TEST_H__

test/test_arithmetic.c

@@ -148,7 +148,7 @@ static mask_t test_mul_sqr (
     return succ;
 }
 
-int test_arithmetic () {
+int test_arithmetic (void) {
     int j, ntests = 100000;
     
     gmp_randstate_t state;

test/test_goldilocks.c

@@ -4,7 +4,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-int test_goldilocks () {
+int test_goldilocks (void) {
     const char *message1 = "hello world";
     const char *message2 = "Jello world";
     

test/test_pointops.c

@@ -249,7 +249,7 @@ single_twisting_test (
     return succ ? 0 : -1;
 }
 
-int test_pointops () {
+int test_pointops (void) {
     struct affine_t base, pbase;
     struct p448_t ser448;
     

test/test_scalarmul.c

@@ -274,7 +274,7 @@ single_scalarmul_commutativity_test (
     }
 }
 
-int test_scalarmul_commutativity () {
+int test_scalarmul_commutativity (void) {
     int i,j,k,got;
     
     struct crandom_state_t crand;
@@ -312,7 +312,7 @@ int test_scalarmul_commutativity () {
     return 0;
 }
 
-int test_linear_combo () {
+int test_linear_combo (void) {
     int i,j,k,got;
     
     struct crandom_state_t crand;
@@ -355,7 +355,7 @@ int test_linear_combo () {
     return 0;
 }
 
-int test_scalarmul_compatibility () {
+int test_scalarmul_compatibility (void) {
     int i,j,k,got;
     
     struct crandom_state_t crand;

test/test_sha512.c

@@ -59,7 +59,7 @@ static int sha512_monte_carlo_core (
     return 0;
 }
 
-int test_sha512_monte_carlo() {
+int test_sha512_monte_carlo(void) {
     const char *seed =
         "5c337de5caf35d18ed90b5cddfce001ca1b8ee8602f367e7c24ccca6f893802f"
         "b1aca7a3dae32dcd60800a59959bc540d63237876b799229ae71a2526fbc52cd";