diff options
| author | Hubert Kario <hkario@redhat.com> | 2023-02-08 14:13:24 +0100 |
|---|---|---|
| committer | Tomas Mraz <tomas@openssl.org> | 2023-02-11 14:56:27 +0100 |
| commit | c062097bf3e305c9c3b90c0941bb58b8cd7baf88 (patch) | |
| tree | 4eb4f23053b999779482f488147f6fd818040d54 /crypto | |
| parent | 9b4015eccca93d401f9a7ee2d88244872983dcc6 (diff) | |
rsa: add msvc intrinsic for non x64 platforms
_umul128() is x86_64 (x64) only, while __umulh() works everywhere, but
doesn't generate optimal code on x64
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20244)
(cherry picked from commit 075652f224479dad2e64b92e791b296177af8705)
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/bn/rsa_sup_mul.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/crypto/bn/rsa_sup_mul.c b/crypto/bn/rsa_sup_mul.c index 0e0d02e194..3b57161b45 100644 --- a/crypto/bn/rsa_sup_mul.c +++ b/crypto/bn/rsa_sup_mul.c @@ -110,12 +110,34 @@ static ossl_inline void _mul_limb(limb_t *hi, limb_t *lo, limb_t a, limb_t b) *lo = (limb_t)t; } #elif (BN_BYTES == 8) && (defined _MSC_VER) -/* https://learn.microsoft.com/en-us/cpp/intrinsics/umul128?view=msvc-170 */ +# if defined(_M_X64) +/* + * on x86_64 (x64) we can use the _umul128 intrinsic to get one `mul` + * instruction to get both high and low 64 bits of the multiplication. + * https://learn.microsoft.com/en-us/cpp/intrinsics/umul128?view=msvc-140 + */ +#include <intrin.h> #pragma intrinsic(_umul128) static ossl_inline void _mul_limb(limb_t *hi, limb_t *lo, limb_t a, limb_t b) { *lo = _umul128(a, b, hi); } +# elif defined(_M_ARM64) || defined (_M_IA64) +/* + * We can't use the __umulh() on x86_64 as then msvc generates two `mul` + * instructions; so use this more portable intrinsic on platforms that + * don't support _umul128 (like aarch64 (ARM64) or ia64) + * https://learn.microsoft.com/en-us/cpp/intrinsics/umulh?view=msvc-140 + */ +#include <intrin.h> +static ossl_inline void _mul_limb(limb_t *hi, limb_t *lo, limb_t a, limb_t b) +{ + *lo = a * b; + *hi = __umulh(a, b); +} +# else +# error Only x64, ARM64 and IA64 supported. +# endif /* defined(_M_X64) */ #else /* * if the compiler doesn't have either a 128bit data type nor a "return |