diff options
| author | Denys Vlasenko <vda.linux@googlemail.com> | 2021-10-06 19:59:39 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2021-10-06 19:59:39 +0200 |
| commit | 87e3f2e9f8a1c99b223b316fbefb5ae49c2a8fe2 (patch) | |
| tree | 0751b9c52ace20c6cff5297fbf1f955b44f30faf | |
| parent | 911344a99889319a7dba8a725a64dc324597f9eb (diff) | |
tls: P256: x86-64 optimized sp_256_sub_8_p256_mod
function old new delta
sp_256_sub_8_p256_mod - 53 +53
sp_256_mont_reduce_8 223 217 -6
sp_256_mont_dbl_8 38 32 -6
sp_256_ecc_mulmod_8 1535 1529 -6
sp_256_proj_point_dbl_8 469 454 -15
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/4 up/down: 53/-33) Total: 20 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | networking/tls_sp_c32.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/networking/tls_sp_c32.c b/networking/tls_sp_c32.c index 14a7c7066..1391cb405 100644 --- a/networking/tls_sp_c32.c +++ b/networking/tls_sp_c32.c @@ -346,8 +346,8 @@ static int sp_256_sub_8(sp_digit* r, const sp_digit* a, const sp_digit* b) #endif } -#if ALLOW_ASM && defined(__GNUC__) && defined(__i386__) /* Sub p256_mod from a into r. (r = a - p256_mod). */ +#if ALLOW_ASM && defined(__GNUC__) && defined(__i386__) static void sp_256_sub_8_p256_mod(sp_digit* r, const sp_digit* a) { sp_digit reg; @@ -390,6 +390,36 @@ static void sp_256_sub_8_p256_mod(sp_digit* r, const sp_digit* a) : "memory" ); } +#elif ALLOW_ASM && defined(__GNUC__) && defined(__x86_64__) +static void sp_256_sub_8_p256_mod(sp_digit* r, const sp_digit* a) +{ + uint64_t reg; + uint64_t ooff; +//p256_mod[3..0] = ffffffff00000001 0000000000000000 00000000ffffffff ffffffffffffffff + asm volatile ( +"\n movq (%0), %3" +"\n addq $1, %3" // adding 1 is the same as subtracting ffffffffffffffff +"\n movq %3, (%1)" // +"\n cmc" // only carry bit needs inverting +"\n" +"\n movq 1*8(%0), %3" +"\n sbbq %2, %3" // %2 holds 00000000ffffffff +"\n movq %3, 1*8(%1)" +"\n" +"\n movq 2*8(%0), %3" +"\n sbbq $0, %3" +"\n movq %3, 2*8(%1)" +"\n" +"\n movq 3*8(%0), %3" +"\n sbbq $0, %3" // adding 00000000ffffffff (in %2) +"\n addq %2, %3" // is the same as subtracting ffffffff00000001 +"\n movq %3, 3*8(%1)" +"\n" + : "=r" (a), "=r" (r), "=r" (ooff), "=r" (reg) + : "0" (a), "1" (r), "2" (0x00000000ffffffff) + : "memory" + ); +} #else # define sp_256_sub_8_p256_mod(r, a) sp_256_sub_8((r), (a), p256_mod) #endif |