diff options
Diffstat (limited to 'src/util.h')
| -rw-r--r-- | src/util.h | 58 |
1 files changed, 51 insertions, 7 deletions
diff --git a/src/util.h b/src/util.h index 8289e23e0c..a5cbe03ef5 100644 --- a/src/util.h +++ b/src/util.h @@ -170,13 +170,35 @@ static SECP256K1_INLINE void *manual_alloc(void** prealloc_ptr, size_t alloc_siz # define I64uFORMAT "llu" #endif -#if defined(HAVE___INT128) -# if defined(__GNUC__) -# define SECP256K1_GNUC_EXT __extension__ -# else -# define SECP256K1_GNUC_EXT +#if defined(__GNUC__) +# define SECP256K1_GNUC_EXT __extension__ +#else +# define SECP256K1_GNUC_EXT +#endif + +/* If SECP256K1_{LITTLE,BIG}_ENDIAN is not explicitly provided, infer from various other system macros. */ +#if !defined(SECP256K1_LITTLE_ENDIAN) && !defined(SECP256K1_BIG_ENDIAN) +/* Inspired by https://github.com/rofl0r/endianness.h/blob/9853923246b065a3b52d2c43835f3819a62c7199/endianness.h#L52L73 */ +# if (defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) || \ + defined(_X86_) || defined(__x86_64__) || defined(__i386__) || \ + defined(__i486__) || defined(__i586__) || defined(__i686__) || \ + defined(__MIPSEL) || defined(_MIPSEL) || defined(MIPSEL) || \ + defined(__ARMEL__) || defined(__AARCH64EL__) || \ + (defined(__LITTLE_ENDIAN__) && __LITTLE_ENDIAN__ == 1) || \ + (defined(_LITTLE_ENDIAN) && _LITTLE_ENDIAN == 1) || \ + defined(_M_IX86) || defined(_M_AMD64) || defined(_M_ARM) /* MSVC */ +# define SECP256K1_LITTLE_ENDIAN # endif -SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; +# if (defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) || \ + defined(__MIPSEB) || defined(_MIPSEB) || defined(MIPSEB) || \ + defined(__MICROBLAZEEB__) || defined(__ARMEB__) || defined(__AARCH64EB__) || \ + (defined(__BIG_ENDIAN__) && __BIG_ENDIAN__ == 1) || \ + (defined(_BIG_ENDIAN) && _BIG_ENDIAN == 1) +# define SECP256K1_BIG_ENDIAN +# endif +#endif +#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. #endif /* Zero memory if flag == 1. Flag must be 0 or 1. Constant time. */ @@ -197,10 +219,15 @@ static SECP256K1_INLINE void memczero(void *s, size_t len, int flag) { /** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. Both *r and *a must be initialized and non-negative.*/ static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) { unsigned int mask0, mask1, r_masked, a_masked; + /* Access flag with a volatile-qualified lvalue. + This prevents clang from figuring out (after inlining) that flag can + take only be 0 or 1, which leads to variable time code. */ + volatile int vflag = flag; + /* Casting a negative int to unsigned and back to int is implementation defined behavior */ VERIFY_CHECK(*r >= 0 && *a >= 0); - mask0 = (unsigned int)flag + ~0u; + mask0 = (unsigned int)vflag + ~0u; mask1 = ~mask0; r_masked = ((unsigned int)*r & mask0); a_masked = ((unsigned int)*a & mask1); @@ -208,4 +235,21 @@ static SECP256K1_INLINE void secp256k1_int_cmov(int *r, const int *a, int flag) *r = (int)(r_masked | a_masked); } +/* If USE_FORCE_WIDEMUL_{INT128,INT64} is set, use that wide multiplication implementation. + * Otherwise use the presence of __SIZEOF_INT128__ to decide. + */ +#if defined(USE_FORCE_WIDEMUL_INT128) +# define SECP256K1_WIDEMUL_INT128 1 +#elif defined(USE_FORCE_WIDEMUL_INT64) +# define SECP256K1_WIDEMUL_INT64 1 +#elif defined(__SIZEOF_INT128__) +# define SECP256K1_WIDEMUL_INT128 1 +#else +# define SECP256K1_WIDEMUL_INT64 1 +#endif +#if defined(SECP256K1_WIDEMUL_INT128) +SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t; +SECP256K1_GNUC_EXT typedef __int128 int128_t; +#endif + #endif /* SECP256K1_UTIL_H */ |