diff options
| -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 14a7c70..1391cb4 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 |