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Differential D9373 Diff 28101 src/secp256k1/src/util.h

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src/secp256k1/src/util.h

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# define SECP256K1_BIG_ENDIAN # define SECP256K1_BIG_ENDIAN
# endif # endif
#endif #endif
#if defined(SECP256K1_LITTLE_ENDIAN) == defined(SECP256K1_BIG_ENDIAN) #if defined(SECP256K1_LITTLE_ENDIAN) == defined(SECP256K1_BIG_ENDIAN)
# error Please make sure that either SECP256K1_LITTLE_ENDIAN or SECP256K1_BIG_ENDIAN is set, see src/util.h. # error Please make sure that either SECP256K1_LITTLE_ENDIAN or SECP256K1_BIG_ENDIAN is set, see src/util.h.
#endif #endif
/* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */ /* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */
static SECP256K1_INLINE void memczero(void *s, size_t len, int flag) { static SECP256K1_INLINE void secp256k1_memczero(void *s, size_t len, int flag) {
unsigned char *p = (unsigned char *)s; unsigned char *p = (unsigned char *)s;
/* Access flag with a volatile-qualified lvalue. /* Access flag with a volatile-qualified lvalue.
This prevents clang from figuring out (after inlining) that flag can This prevents clang from figuring out (after inlining) that flag can
take only be 0 or 1, which leads to variable time code. */ take only be 0 or 1, which leads to variable time code. */
volatile int vflag = flag; volatile int vflag = flag;
unsigned char mask = -(unsigned char) vflag; unsigned char mask = -(unsigned char) vflag;
while (len) { while (len) {
*p &= ~mask; *p &= ~mask;
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/* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation. /* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation.
* Otherwise use the presence of __SIZEOF_INT128__ to decide. * Otherwise use the presence of __SIZEOF_INT128__ to decide.
*/ */
#if defined(USE_FORCE_WIDEMUL_INT128) #if defined(USE_FORCE_WIDEMUL_INT128)
# define SECP256K1_WIDEMUL_INT128 1 # define SECP256K1_WIDEMUL_INT128 1
#elif defined(USE_FORCE_WIDEMUL_INT64) #elif defined(USE_FORCE_WIDEMUL_INT64)
# define SECP256K1_WIDEMUL_INT64 1 # define SECP256K1_WIDEMUL_INT64 1
#elif defined(__SIZEOF_INT128__) #elif defined(UINT128_MAX) || defined(__SIZEOF_INT128__)
# define SECP256K1_WIDEMUL_INT128 1 # define SECP256K1_WIDEMUL_INT128 1
#else #else
# define SECP256K1_WIDEMUL_INT64 1 # define SECP256K1_WIDEMUL_INT64 1
#endif #endif
#if defined(SECP256K1_WIDEMUL_INT128) #if defined(SECP256K1_WIDEMUL_INT128)
# if !defined(UINT128_MAX) && defined(__SIZEOF_INT128__)
SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t;
SECP256K1_GNUC_EXT typedef __int128 int128_t; SECP256K1_GNUC_EXT typedef __int128 int128_t;
#define UINT128_MAX ((uint128_t)(-1))
#define INT128_MAX ((int128_t)(UINT128_MAX >> 1))
#define INT128_MIN (-INT128_MAX - 1)
/* No (U)INT128_C macros because compilers providing __int128 do not support 128-bit literals. */
# endif
#endif #endif
#endif /* SECP256K1_UTIL_H */ #endif /* SECP256K1_UTIL_H */