diff options
| author | Denys Vlasenko <vda.linux@googlemail.com> | 2021-10-06 14:25:10 +0200 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2021-10-06 14:25:54 +0200 |
| commit | 567eefcaf8712b72c3cd5b45aa013ff1eb45d235 (patch) | |
| tree | cd91aa2419c3234026d5de4d102de4f2f849fcba | |
| parent | 00f2cceb6aa194aadcbe70675a0f0a0660aea233 (diff) | |
tls: P256: do not dumplicate sp_256_sub_8()
function old new delta
sp_256_proj_point_dbl_8 359 374 +15
sp_256_ecc_mulmod_8 1159 1171 +12
sp_256_mont_reduce_8 245 250 +5
sp_256_mont_dbl_8 26 31 +5
sp_256_sub_8_p256_mod 43 - -43
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 4/0 up/down: 37/-43) Total: -6 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | networking/tls_sp_c32.c | 26 |
1 files changed, 3 insertions, 23 deletions
diff --git a/networking/tls_sp_c32.c b/networking/tls_sp_c32.c index 6fca2aad8..17fc05f63 100644 --- a/networking/tls_sp_c32.c +++ b/networking/tls_sp_c32.c @@ -291,10 +291,10 @@ 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). */ static void sp_256_sub_8_p256_mod(sp_digit* r, const sp_digit* a) { -#if ALLOW_ASM && defined(__GNUC__) && defined(__i386__) sp_digit reg; //p256_mod[7..0] = ffffffff 00000001 00000000 00000000 00000000 ffffffff ffffffff ffffffff asm volatile ( @@ -334,30 +334,10 @@ static void sp_256_sub_8_p256_mod(sp_digit* r, const sp_digit* a) : "0" (a), "1" (r) : "memory" ); +} #else - const sp_digit* b = p256_mod; - int i; - sp_digit borrow; - - borrow = 0; - for (i = 0; i < 8; i++) { - sp_digit w, v; - w = b[i] + borrow; - v = a[i]; - if (w != 0) { - v = a[i] - w; - borrow = (v > a[i]); - /* hope compiler detects above as "carry flag set" */ - } - /* else: b + borrow == 0, two cases: - * b:ffffffff, borrow:1 - * b:00000000, borrow:0 - * in either case, r[i] = a[i] and borrow remains unchanged - */ - r[i] = v; - } +# define sp_256_sub_8_p256_mod(r, a) sp_256_sub_8((r), (a), p256_mod) #endif -} /* Multiply a and b into r. (r = a * b) */ static void sp_256_mul_8(sp_digit* r, const sp_digit* a, const sp_digit* b) |