diff options
Diffstat (limited to 'crypto/secp256k1/libsecp256k1/src/scalar_4x64_impl.h')
-rw-r--r-- | crypto/secp256k1/libsecp256k1/src/scalar_4x64_impl.h | 949 |
1 files changed, 949 insertions, 0 deletions
diff --git a/crypto/secp256k1/libsecp256k1/src/scalar_4x64_impl.h b/crypto/secp256k1/libsecp256k1/src/scalar_4x64_impl.h new file mode 100644 index 000000000..56e7bd82a --- /dev/null +++ b/crypto/secp256k1/libsecp256k1/src/scalar_4x64_impl.h @@ -0,0 +1,949 @@ +/********************************************************************** + * Copyright (c) 2013, 2014 Pieter Wuille * + * Distributed under the MIT software license, see the accompanying * + * file COPYING or http://www.opensource.org/licenses/mit-license.php.* + **********************************************************************/ + +#ifndef _SECP256K1_SCALAR_REPR_IMPL_H_ +#define _SECP256K1_SCALAR_REPR_IMPL_H_ + +/* Limbs of the secp256k1 order. */ +#define SECP256K1_N_0 ((uint64_t)0xBFD25E8CD0364141ULL) +#define SECP256K1_N_1 ((uint64_t)0xBAAEDCE6AF48A03BULL) +#define SECP256K1_N_2 ((uint64_t)0xFFFFFFFFFFFFFFFEULL) +#define SECP256K1_N_3 ((uint64_t)0xFFFFFFFFFFFFFFFFULL) + +/* Limbs of 2^256 minus the secp256k1 order. */ +#define SECP256K1_N_C_0 (~SECP256K1_N_0 + 1) +#define SECP256K1_N_C_1 (~SECP256K1_N_1) +#define SECP256K1_N_C_2 (1) + +/* Limbs of half the secp256k1 order. */ +#define SECP256K1_N_H_0 ((uint64_t)0xDFE92F46681B20A0ULL) +#define SECP256K1_N_H_1 ((uint64_t)0x5D576E7357A4501DULL) +#define SECP256K1_N_H_2 ((uint64_t)0xFFFFFFFFFFFFFFFFULL) +#define SECP256K1_N_H_3 ((uint64_t)0x7FFFFFFFFFFFFFFFULL) + +SECP256K1_INLINE static void secp256k1_scalar_clear(secp256k1_scalar *r) { + r->d[0] = 0; + r->d[1] = 0; + r->d[2] = 0; + r->d[3] = 0; +} + +SECP256K1_INLINE static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsigned int v) { + r->d[0] = v; + r->d[1] = 0; + r->d[2] = 0; + r->d[3] = 0; +} + +SECP256K1_INLINE static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count) { + VERIFY_CHECK((offset + count - 1) >> 6 == offset >> 6); + return (a->d[offset >> 6] >> (offset & 0x3F)) & ((((uint64_t)1) << count) - 1); +} + +SECP256K1_INLINE static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count) { + VERIFY_CHECK(count < 32); + VERIFY_CHECK(offset + count <= 256); + if ((offset + count - 1) >> 6 == offset >> 6) { + return secp256k1_scalar_get_bits(a, offset, count); + } else { + VERIFY_CHECK((offset >> 6) + 1 < 4); + return ((a->d[offset >> 6] >> (offset & 0x3F)) | (a->d[(offset >> 6) + 1] << (64 - (offset & 0x3F)))) & ((((uint64_t)1) << count) - 1); + } +} + +SECP256K1_INLINE static int secp256k1_scalar_check_overflow(const secp256k1_scalar *a) { + int yes = 0; + int no = 0; + no |= (a->d[3] < SECP256K1_N_3); /* No need for a > check. */ + no |= (a->d[2] < SECP256K1_N_2); + yes |= (a->d[2] > SECP256K1_N_2) & ~no; + no |= (a->d[1] < SECP256K1_N_1); + yes |= (a->d[1] > SECP256K1_N_1) & ~no; + yes |= (a->d[0] >= SECP256K1_N_0) & ~no; + return yes; +} + +SECP256K1_INLINE static int secp256k1_scalar_reduce(secp256k1_scalar *r, unsigned int overflow) { + uint128_t t; + VERIFY_CHECK(overflow <= 1); + t = (uint128_t)r->d[0] + overflow * SECP256K1_N_C_0; + r->d[0] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)r->d[1] + overflow * SECP256K1_N_C_1; + r->d[1] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)r->d[2] + overflow * SECP256K1_N_C_2; + r->d[2] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint64_t)r->d[3]; + r->d[3] = t & 0xFFFFFFFFFFFFFFFFULL; + return overflow; +} + +static int secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b) { + int overflow; + uint128_t t = (uint128_t)a->d[0] + b->d[0]; + r->d[0] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)a->d[1] + b->d[1]; + r->d[1] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)a->d[2] + b->d[2]; + r->d[2] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)a->d[3] + b->d[3]; + r->d[3] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + overflow = t + secp256k1_scalar_check_overflow(r); + VERIFY_CHECK(overflow == 0 || overflow == 1); + secp256k1_scalar_reduce(r, overflow); + return overflow; +} + +static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag) { + uint128_t t; + VERIFY_CHECK(bit < 256); + bit += ((uint32_t) flag - 1) & 0x100; /* forcing (bit >> 6) > 3 makes this a noop */ + t = (uint128_t)r->d[0] + (((uint64_t)((bit >> 6) == 0)) << (bit & 0x3F)); + r->d[0] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)r->d[1] + (((uint64_t)((bit >> 6) == 1)) << (bit & 0x3F)); + r->d[1] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)r->d[2] + (((uint64_t)((bit >> 6) == 2)) << (bit & 0x3F)); + r->d[2] = t & 0xFFFFFFFFFFFFFFFFULL; t >>= 64; + t += (uint128_t)r->d[3] + (((uint64_t)((bit >> 6) == 3)) << (bit & 0x3F)); + r->d[3] = t & 0xFFFFFFFFFFFFFFFFULL; +#ifdef VERIFY + VERIFY_CHECK((t >> 64) == 0); + VERIFY_CHECK(secp256k1_scalar_check_overflow(r) == 0); +#endif +} + +static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *b32, int *overflow) { + int over; + r->d[0] = (uint64_t)b32[31] | (uint64_t)b32[30] << 8 | (uint64_t)b32[29] << 16 | (uint64_t)b32[28] << 24 | (uint64_t)b32[27] << 32 | (uint64_t)b32[26] << 40 | (uint64_t)b32[25] << 48 | (uint64_t)b32[24] << 56; + r->d[1] = (uint64_t)b32[23] | (uint64_t)b32[22] << 8 | (uint64_t)b32[21] << 16 | (uint64_t)b32[20] << 24 | (uint64_t)b32[19] << 32 | (uint64_t)b32[18] << 40 | (uint64_t)b32[17] << 48 | (uint64_t)b32[16] << 56; + r->d[2] = (uint64_t)b32[15] | (uint64_t)b32[14] << 8 | (uint64_t)b32[13] << 16 | (uint64_t)b32[12] << 24 | (uint64_t)b32[11] << 32 | (uint64_t)b32[10] << 40 | (uint64_t)b32[9] << 48 | (uint64_t)b32[8] << 56; + r->d[3] = (uint64_t)b32[7] | (uint64_t)b32[6] << 8 | (uint64_t)b32[5] << 16 | (uint64_t)b32[4] << 24 | (uint64_t)b32[3] << 32 | (uint64_t)b32[2] << 40 | (uint64_t)b32[1] << 48 | (uint64_t)b32[0] << 56; + over = secp256k1_scalar_reduce(r, secp256k1_scalar_check_overflow(r)); + if (overflow) { + *overflow = over; + } +} + +static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar* a) { + bin[0] = a->d[3] >> 56; bin[1] = a->d[3] >> 48; bin[2] = a->d[3] >> 40; bin[3] = a->d[3] >> 32; bin[4] = a->d[3] >> 24; bin[5] = a->d[3] >> 16; bin[6] = a->d[3] >> 8; bin[7] = a->d[3]; + bin[8] = a->d[2] >> 56; bin[9] = a->d[2] >> 48; bin[10] = a->d[2] >> 40; bin[11] = a->d[2] >> 32; bin[12] = a->d[2] >> 24; bin[13] = a->d[2] >> 16; bin[14] = a->d[2] >> 8; bin[15] = a->d[2]; + bin[16] = a->d[1] >> 56; bin[17] = a->d[1] >> 48; bin[18] = a->d[1] >> 40; bin[19] = a->d[1] >> 32; bin[20] = a->d[1] >> 24; bin[21] = a->d[1] >> 16; bin[22] = a->d[1] >> 8; bin[23] = a->d[1]; + bin[24] = a->d[0] >> 56; bin[25] = a->d[0] >> 48; bin[26] = a->d[0] >> 40; bin[27] = a->d[0] >> 32; bin[28] = a->d[0] >> 24; bin[29] = a->d[0] >> 16; bin[30] = a->d[0] >> 8; bin[31] = a->d[0]; +} + +SECP256K1_INLINE static int secp256k1_scalar_is_zero(const secp256k1_scalar *a) { + return (a->d[0] | a->d[1] | a->d[2] | a->d[3]) == 0; +} + +static void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar *a) { + uint64_t nonzero = 0xFFFFFFFFFFFFFFFFULL * (secp256k1_scalar_is_zero(a) == 0); + uint128_t t = (uint128_t)(~a->d[0]) + SECP256K1_N_0 + 1; + r->d[0] = t & nonzero; t >>= 64; + t += (uint128_t)(~a->d[1]) + SECP256K1_N_1; + r->d[1] = t & nonzero; t >>= 64; + t += (uint128_t)(~a->d[2]) + SECP256K1_N_2; + r->d[2] = t & nonzero; t >>= 64; + t += (uint128_t)(~a->d[3]) + SECP256K1_N_3; + r->d[3] = t & nonzero; +} + +SECP256K1_INLINE static int secp256k1_scalar_is_one(const secp256k1_scalar *a) { + return ((a->d[0] ^ 1) | a->d[1] | a->d[2] | a->d[3]) == 0; +} + +static int secp256k1_scalar_is_high(const secp256k1_scalar *a) { + int yes = 0; + int no = 0; + no |= (a->d[3] < SECP256K1_N_H_3); + yes |= (a->d[3] > SECP256K1_N_H_3) & ~no; + no |= (a->d[2] < SECP256K1_N_H_2) & ~yes; /* No need for a > check. */ + no |= (a->d[1] < SECP256K1_N_H_1) & ~yes; + yes |= (a->d[1] > SECP256K1_N_H_1) & ~no; + yes |= (a->d[0] > SECP256K1_N_H_0) & ~no; + return yes; +} + +static int secp256k1_scalar_cond_negate(secp256k1_scalar *r, int flag) { + /* If we are flag = 0, mask = 00...00 and this is a no-op; + * if we are flag = 1, mask = 11...11 and this is identical to secp256k1_scalar_negate */ + uint64_t mask = !flag - 1; + uint64_t nonzero = (secp256k1_scalar_is_zero(r) != 0) - 1; + uint128_t t = (uint128_t)(r->d[0] ^ mask) + ((SECP256K1_N_0 + 1) & mask); + r->d[0] = t & nonzero; t >>= 64; + t += (uint128_t)(r->d[1] ^ mask) + (SECP256K1_N_1 & mask); + r->d[1] = t & nonzero; t >>= 64; + t += (uint128_t)(r->d[2] ^ mask) + (SECP256K1_N_2 & mask); + r->d[2] = t & nonzero; t >>= 64; + t += (uint128_t)(r->d[3] ^ mask) + (SECP256K1_N_3 & mask); + r->d[3] = t & nonzero; + return 2 * (mask == 0) - 1; +} + +/* Inspired by the macros in OpenSSL's crypto/bn/asm/x86_64-gcc.c. */ + +/** Add a*b to the number defined by (c0,c1,c2). c2 must never overflow. */ +#define muladd(a,b) { \ + uint64_t tl, th; \ + { \ + uint128_t t = (uint128_t)a * b; \ + th = t >> 64; /* at most 0xFFFFFFFFFFFFFFFE */ \ + tl = t; \ + } \ + c0 += tl; /* overflow is handled on the next line */ \ + th += (c0 < tl) ? 1 : 0; /* at most 0xFFFFFFFFFFFFFFFF */ \ + c1 += th; /* overflow is handled on the next line */ \ + c2 += (c1 < th) ? 1 : 0; /* never overflows by contract (verified in the next line) */ \ + VERIFY_CHECK((c1 >= th) || (c2 != 0)); \ +} + +/** Add a*b to the number defined by (c0,c1). c1 must never overflow. */ +#define muladd_fast(a,b) { \ + uint64_t tl, th; \ + { \ + uint128_t t = (uint128_t)a * b; \ + th = t >> 64; /* at most 0xFFFFFFFFFFFFFFFE */ \ + tl = t; \ + } \ + c0 += tl; /* overflow is handled on the next line */ \ + th += (c0 < tl) ? 1 : 0; /* at most 0xFFFFFFFFFFFFFFFF */ \ + c1 += th; /* never overflows by contract (verified in the next line) */ \ + VERIFY_CHECK(c1 >= th); \ +} + +/** Add 2*a*b to the number defined by (c0,c1,c2). c2 must never overflow. */ +#define muladd2(a,b) { \ + uint64_t tl, th, th2, tl2; \ + { \ + uint128_t t = (uint128_t)a * b; \ + th = t >> 64; /* at most 0xFFFFFFFFFFFFFFFE */ \ + tl = t; \ + } \ + th2 = th + th; /* at most 0xFFFFFFFFFFFFFFFE (in case th was 0x7FFFFFFFFFFFFFFF) */ \ + c2 += (th2 < th) ? 1 : 0; /* never overflows by contract (verified the next line) */ \ + VERIFY_CHECK((th2 >= th) || (c2 != 0)); \ + tl2 = tl + tl; /* at most 0xFFFFFFFFFFFFFFFE (in case the lowest 63 bits of tl were 0x7FFFFFFFFFFFFFFF) */ \ + th2 += (tl2 < tl) ? 1 : 0; /* at most 0xFFFFFFFFFFFFFFFF */ \ + c0 += tl2; /* overflow is handled on the next line */ \ + th2 += (c0 < tl2) ? 1 : 0; /* second overflow is handled on the next line */ \ + c2 += (c0 < tl2) & (th2 == 0); /* never overflows by contract (verified the next line) */ \ + VERIFY_CHECK((c0 >= tl2) || (th2 != 0) || (c2 != 0)); \ + c1 += th2; /* overflow is handled on the next line */ \ + c2 += (c1 < th2) ? 1 : 0; /* never overflows by contract (verified the next line) */ \ + VERIFY_CHECK((c1 >= th2) || (c2 != 0)); \ +} + +/** Add a to the number defined by (c0,c1,c2). c2 must never overflow. */ +#define sumadd(a) { \ + unsigned int over; \ + c0 += (a); /* overflow is handled on the next line */ \ + over = (c0 < (a)) ? 1 : 0; \ + c1 += over; /* overflow is handled on the next line */ \ + c2 += (c1 < over) ? 1 : 0; /* never overflows by contract */ \ +} + +/** Add a to the number defined by (c0,c1). c1 must never overflow, c2 must be zero. */ +#define sumadd_fast(a) { \ + c0 += (a); /* overflow is handled on the next line */ \ + c1 += (c0 < (a)) ? 1 : 0; /* never overflows by contract (verified the next line) */ \ + VERIFY_CHECK((c1 != 0) | (c0 >= (a))); \ + VERIFY_CHECK(c2 == 0); \ +} + +/** Extract the lowest 64 bits of (c0,c1,c2) into n, and left shift the number 64 bits. */ +#define extract(n) { \ + (n) = c0; \ + c0 = c1; \ + c1 = c2; \ + c2 = 0; \ +} + +/** Extract the lowest 64 bits of (c0,c1,c2) into n, and left shift the number 64 bits. c2 is required to be zero. */ +#define extract_fast(n) { \ + (n) = c0; \ + c0 = c1; \ + c1 = 0; \ + VERIFY_CHECK(c2 == 0); \ +} + +static void secp256k1_scalar_reduce_512(secp256k1_scalar *r, const uint64_t *l) { +#ifdef USE_ASM_X86_64 + /* Reduce 512 bits into 385. */ + uint64_t m0, m1, m2, m3, m4, m5, m6; + uint64_t p0, p1, p2, p3, p4; + uint64_t c; + + __asm__ __volatile__( + /* Preload. */ + "movq 32(%%rsi), %%r11\n" + "movq 40(%%rsi), %%r12\n" + "movq 48(%%rsi), %%r13\n" + "movq 56(%%rsi), %%r14\n" + /* Initialize r8,r9,r10 */ + "movq 0(%%rsi), %%r8\n" + "xorq %%r9, %%r9\n" + "xorq %%r10, %%r10\n" + /* (r8,r9) += n0 * c0 */ + "movq %8, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + /* extract m0 */ + "movq %%r8, %q0\n" + "xorq %%r8, %%r8\n" + /* (r9,r10) += l1 */ + "addq 8(%%rsi), %%r9\n" + "adcq $0, %%r10\n" + /* (r9,r10,r8) += n1 * c0 */ + "movq %8, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += n0 * c1 */ + "movq %9, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* extract m1 */ + "movq %%r9, %q1\n" + "xorq %%r9, %%r9\n" + /* (r10,r8,r9) += l2 */ + "addq 16(%%rsi), %%r10\n" + "adcq $0, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += n2 * c0 */ + "movq %8, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += n1 * c1 */ + "movq %9, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += n0 */ + "addq %%r11, %%r10\n" + "adcq $0, %%r8\n" + "adcq $0, %%r9\n" + /* extract m2 */ + "movq %%r10, %q2\n" + "xorq %%r10, %%r10\n" + /* (r8,r9,r10) += l3 */ + "addq 24(%%rsi), %%r8\n" + "adcq $0, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += n3 * c0 */ + "movq %8, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += n2 * c1 */ + "movq %9, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += n1 */ + "addq %%r12, %%r8\n" + "adcq $0, %%r9\n" + "adcq $0, %%r10\n" + /* extract m3 */ + "movq %%r8, %q3\n" + "xorq %%r8, %%r8\n" + /* (r9,r10,r8) += n3 * c1 */ + "movq %9, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += n2 */ + "addq %%r13, %%r9\n" + "adcq $0, %%r10\n" + "adcq $0, %%r8\n" + /* extract m4 */ + "movq %%r9, %q4\n" + /* (r10,r8) += n3 */ + "addq %%r14, %%r10\n" + "adcq $0, %%r8\n" + /* extract m5 */ + "movq %%r10, %q5\n" + /* extract m6 */ + "movq %%r8, %q6\n" + : "=g"(m0), "=g"(m1), "=g"(m2), "=g"(m3), "=g"(m4), "=g"(m5), "=g"(m6) + : "S"(l), "n"(SECP256K1_N_C_0), "n"(SECP256K1_N_C_1) + : "rax", "rdx", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "cc"); + + /* Reduce 385 bits into 258. */ + __asm__ __volatile__( + /* Preload */ + "movq %q9, %%r11\n" + "movq %q10, %%r12\n" + "movq %q11, %%r13\n" + /* Initialize (r8,r9,r10) */ + "movq %q5, %%r8\n" + "xorq %%r9, %%r9\n" + "xorq %%r10, %%r10\n" + /* (r8,r9) += m4 * c0 */ + "movq %12, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + /* extract p0 */ + "movq %%r8, %q0\n" + "xorq %%r8, %%r8\n" + /* (r9,r10) += m1 */ + "addq %q6, %%r9\n" + "adcq $0, %%r10\n" + /* (r9,r10,r8) += m5 * c0 */ + "movq %12, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += m4 * c1 */ + "movq %13, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* extract p1 */ + "movq %%r9, %q1\n" + "xorq %%r9, %%r9\n" + /* (r10,r8,r9) += m2 */ + "addq %q7, %%r10\n" + "adcq $0, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += m6 * c0 */ + "movq %12, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += m5 * c1 */ + "movq %13, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += m4 */ + "addq %%r11, %%r10\n" + "adcq $0, %%r8\n" + "adcq $0, %%r9\n" + /* extract p2 */ + "movq %%r10, %q2\n" + /* (r8,r9) += m3 */ + "addq %q8, %%r8\n" + "adcq $0, %%r9\n" + /* (r8,r9) += m6 * c1 */ + "movq %13, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + /* (r8,r9) += m5 */ + "addq %%r12, %%r8\n" + "adcq $0, %%r9\n" + /* extract p3 */ + "movq %%r8, %q3\n" + /* (r9) += m6 */ + "addq %%r13, %%r9\n" + /* extract p4 */ + "movq %%r9, %q4\n" + : "=&g"(p0), "=&g"(p1), "=&g"(p2), "=g"(p3), "=g"(p4) + : "g"(m0), "g"(m1), "g"(m2), "g"(m3), "g"(m4), "g"(m5), "g"(m6), "n"(SECP256K1_N_C_0), "n"(SECP256K1_N_C_1) + : "rax", "rdx", "r8", "r9", "r10", "r11", "r12", "r13", "cc"); + + /* Reduce 258 bits into 256. */ + __asm__ __volatile__( + /* Preload */ + "movq %q5, %%r10\n" + /* (rax,rdx) = p4 * c0 */ + "movq %7, %%rax\n" + "mulq %%r10\n" + /* (rax,rdx) += p0 */ + "addq %q1, %%rax\n" + "adcq $0, %%rdx\n" + /* extract r0 */ + "movq %%rax, 0(%q6)\n" + /* Move to (r8,r9) */ + "movq %%rdx, %%r8\n" + "xorq %%r9, %%r9\n" + /* (r8,r9) += p1 */ + "addq %q2, %%r8\n" + "adcq $0, %%r9\n" + /* (r8,r9) += p4 * c1 */ + "movq %8, %%rax\n" + "mulq %%r10\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + /* Extract r1 */ + "movq %%r8, 8(%q6)\n" + "xorq %%r8, %%r8\n" + /* (r9,r8) += p4 */ + "addq %%r10, %%r9\n" + "adcq $0, %%r8\n" + /* (r9,r8) += p2 */ + "addq %q3, %%r9\n" + "adcq $0, %%r8\n" + /* Extract r2 */ + "movq %%r9, 16(%q6)\n" + "xorq %%r9, %%r9\n" + /* (r8,r9) += p3 */ + "addq %q4, %%r8\n" + "adcq $0, %%r9\n" + /* Extract r3 */ + "movq %%r8, 24(%q6)\n" + /* Extract c */ + "movq %%r9, %q0\n" + : "=g"(c) + : "g"(p0), "g"(p1), "g"(p2), "g"(p3), "g"(p4), "D"(r), "n"(SECP256K1_N_C_0), "n"(SECP256K1_N_C_1) + : "rax", "rdx", "r8", "r9", "r10", "cc", "memory"); +#else + uint128_t c; + uint64_t c0, c1, c2; + uint64_t n0 = l[4], n1 = l[5], n2 = l[6], n3 = l[7]; + uint64_t m0, m1, m2, m3, m4, m5; + uint32_t m6; + uint64_t p0, p1, p2, p3; + uint32_t p4; + + /* Reduce 512 bits into 385. */ + /* m[0..6] = l[0..3] + n[0..3] * SECP256K1_N_C. */ + c0 = l[0]; c1 = 0; c2 = 0; + muladd_fast(n0, SECP256K1_N_C_0); + extract_fast(m0); + sumadd_fast(l[1]); + muladd(n1, SECP256K1_N_C_0); + muladd(n0, SECP256K1_N_C_1); + extract(m1); + sumadd(l[2]); + muladd(n2, SECP256K1_N_C_0); + muladd(n1, SECP256K1_N_C_1); + sumadd(n0); + extract(m2); + sumadd(l[3]); + muladd(n3, SECP256K1_N_C_0); + muladd(n2, SECP256K1_N_C_1); + sumadd(n1); + extract(m3); + muladd(n3, SECP256K1_N_C_1); + sumadd(n2); + extract(m4); + sumadd_fast(n3); + extract_fast(m5); + VERIFY_CHECK(c0 <= 1); + m6 = c0; + + /* Reduce 385 bits into 258. */ + /* p[0..4] = m[0..3] + m[4..6] * SECP256K1_N_C. */ + c0 = m0; c1 = 0; c2 = 0; + muladd_fast(m4, SECP256K1_N_C_0); + extract_fast(p0); + sumadd_fast(m1); + muladd(m5, SECP256K1_N_C_0); + muladd(m4, SECP256K1_N_C_1); + extract(p1); + sumadd(m2); + muladd(m6, SECP256K1_N_C_0); + muladd(m5, SECP256K1_N_C_1); + sumadd(m4); + extract(p2); + sumadd_fast(m3); + muladd_fast(m6, SECP256K1_N_C_1); + sumadd_fast(m5); + extract_fast(p3); + p4 = c0 + m6; + VERIFY_CHECK(p4 <= 2); + + /* Reduce 258 bits into 256. */ + /* r[0..3] = p[0..3] + p[4] * SECP256K1_N_C. */ + c = p0 + (uint128_t)SECP256K1_N_C_0 * p4; + r->d[0] = c & 0xFFFFFFFFFFFFFFFFULL; c >>= 64; + c += p1 + (uint128_t)SECP256K1_N_C_1 * p4; + r->d[1] = c & 0xFFFFFFFFFFFFFFFFULL; c >>= 64; + c += p2 + (uint128_t)p4; + r->d[2] = c & 0xFFFFFFFFFFFFFFFFULL; c >>= 64; + c += p3; + r->d[3] = c & 0xFFFFFFFFFFFFFFFFULL; c >>= 64; +#endif + + /* Final reduction of r. */ + secp256k1_scalar_reduce(r, c + secp256k1_scalar_check_overflow(r)); +} + +static void secp256k1_scalar_mul_512(uint64_t l[8], const secp256k1_scalar *a, const secp256k1_scalar *b) { +#ifdef USE_ASM_X86_64 + const uint64_t *pb = b->d; + __asm__ __volatile__( + /* Preload */ + "movq 0(%%rdi), %%r15\n" + "movq 8(%%rdi), %%rbx\n" + "movq 16(%%rdi), %%rcx\n" + "movq 0(%%rdx), %%r11\n" + "movq 8(%%rdx), %%r12\n" + "movq 16(%%rdx), %%r13\n" + "movq 24(%%rdx), %%r14\n" + /* (rax,rdx) = a0 * b0 */ + "movq %%r15, %%rax\n" + "mulq %%r11\n" + /* Extract l0 */ + "movq %%rax, 0(%%rsi)\n" + /* (r8,r9,r10) = (rdx) */ + "movq %%rdx, %%r8\n" + "xorq %%r9, %%r9\n" + "xorq %%r10, %%r10\n" + /* (r8,r9,r10) += a0 * b1 */ + "movq %%r15, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += a1 * b0 */ + "movq %%rbx, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* Extract l1 */ + "movq %%r8, 8(%%rsi)\n" + "xorq %%r8, %%r8\n" + /* (r9,r10,r8) += a0 * b2 */ + "movq %%r15, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += a1 * b1 */ + "movq %%rbx, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += a2 * b0 */ + "movq %%rcx, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* Extract l2 */ + "movq %%r9, 16(%%rsi)\n" + "xorq %%r9, %%r9\n" + /* (r10,r8,r9) += a0 * b3 */ + "movq %%r15, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* Preload a3 */ + "movq 24(%%rdi), %%r15\n" + /* (r10,r8,r9) += a1 * b2 */ + "movq %%rbx, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += a2 * b1 */ + "movq %%rcx, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += a3 * b0 */ + "movq %%r15, %%rax\n" + "mulq %%r11\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* Extract l3 */ + "movq %%r10, 24(%%rsi)\n" + "xorq %%r10, %%r10\n" + /* (r8,r9,r10) += a1 * b3 */ + "movq %%rbx, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += a2 * b2 */ + "movq %%rcx, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += a3 * b1 */ + "movq %%r15, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* Extract l4 */ + "movq %%r8, 32(%%rsi)\n" + "xorq %%r8, %%r8\n" + /* (r9,r10,r8) += a2 * b3 */ + "movq %%rcx, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += a3 * b2 */ + "movq %%r15, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* Extract l5 */ + "movq %%r9, 40(%%rsi)\n" + /* (r10,r8) += a3 * b3 */ + "movq %%r15, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + /* Extract l6 */ + "movq %%r10, 48(%%rsi)\n" + /* Extract l7 */ + "movq %%r8, 56(%%rsi)\n" + : "+d"(pb) + : "S"(l), "D"(a->d) + : "rax", "rbx", "rcx", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "cc", "memory"); +#else + /* 160 bit accumulator. */ + uint64_t c0 = 0, c1 = 0; + uint32_t c2 = 0; + + /* l[0..7] = a[0..3] * b[0..3]. */ + muladd_fast(a->d[0], b->d[0]); + extract_fast(l[0]); + muladd(a->d[0], b->d[1]); + muladd(a->d[1], b->d[0]); + extract(l[1]); + muladd(a->d[0], b->d[2]); + muladd(a->d[1], b->d[1]); + muladd(a->d[2], b->d[0]); + extract(l[2]); + muladd(a->d[0], b->d[3]); + muladd(a->d[1], b->d[2]); + muladd(a->d[2], b->d[1]); + muladd(a->d[3], b->d[0]); + extract(l[3]); + muladd(a->d[1], b->d[3]); + muladd(a->d[2], b->d[2]); + muladd(a->d[3], b->d[1]); + extract(l[4]); + muladd(a->d[2], b->d[3]); + muladd(a->d[3], b->d[2]); + extract(l[5]); + muladd_fast(a->d[3], b->d[3]); + extract_fast(l[6]); + VERIFY_CHECK(c1 == 0); + l[7] = c0; +#endif +} + +static void secp256k1_scalar_sqr_512(uint64_t l[8], const secp256k1_scalar *a) { +#ifdef USE_ASM_X86_64 + __asm__ __volatile__( + /* Preload */ + "movq 0(%%rdi), %%r11\n" + "movq 8(%%rdi), %%r12\n" + "movq 16(%%rdi), %%r13\n" + "movq 24(%%rdi), %%r14\n" + /* (rax,rdx) = a0 * a0 */ + "movq %%r11, %%rax\n" + "mulq %%r11\n" + /* Extract l0 */ + "movq %%rax, 0(%%rsi)\n" + /* (r8,r9,r10) = (rdx,0) */ + "movq %%rdx, %%r8\n" + "xorq %%r9, %%r9\n" + "xorq %%r10, %%r10\n" + /* (r8,r9,r10) += 2 * a0 * a1 */ + "movq %%r11, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* Extract l1 */ + "movq %%r8, 8(%%rsi)\n" + "xorq %%r8, %%r8\n" + /* (r9,r10,r8) += 2 * a0 * a2 */ + "movq %%r11, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* (r9,r10,r8) += a1 * a1 */ + "movq %%r12, %%rax\n" + "mulq %%r12\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* Extract l2 */ + "movq %%r9, 16(%%rsi)\n" + "xorq %%r9, %%r9\n" + /* (r10,r8,r9) += 2 * a0 * a3 */ + "movq %%r11, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* (r10,r8,r9) += 2 * a1 * a2 */ + "movq %%r12, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + "adcq $0, %%r9\n" + /* Extract l3 */ + "movq %%r10, 24(%%rsi)\n" + "xorq %%r10, %%r10\n" + /* (r8,r9,r10) += 2 * a1 * a3 */ + "movq %%r12, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* (r8,r9,r10) += a2 * a2 */ + "movq %%r13, %%rax\n" + "mulq %%r13\n" + "addq %%rax, %%r8\n" + "adcq %%rdx, %%r9\n" + "adcq $0, %%r10\n" + /* Extract l4 */ + "movq %%r8, 32(%%rsi)\n" + "xorq %%r8, %%r8\n" + /* (r9,r10,r8) += 2 * a2 * a3 */ + "movq %%r13, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + "addq %%rax, %%r9\n" + "adcq %%rdx, %%r10\n" + "adcq $0, %%r8\n" + /* Extract l5 */ + "movq %%r9, 40(%%rsi)\n" + /* (r10,r8) += a3 * a3 */ + "movq %%r14, %%rax\n" + "mulq %%r14\n" + "addq %%rax, %%r10\n" + "adcq %%rdx, %%r8\n" + /* Extract l6 */ + "movq %%r10, 48(%%rsi)\n" + /* Extract l7 */ + "movq %%r8, 56(%%rsi)\n" + : + : "S"(l), "D"(a->d) + : "rax", "rdx", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "cc", "memory"); +#else + /* 160 bit accumulator. */ + uint64_t c0 = 0, c1 = 0; + uint32_t c2 = 0; + + /* l[0..7] = a[0..3] * b[0..3]. */ + muladd_fast(a->d[0], a->d[0]); + extract_fast(l[0]); + muladd2(a->d[0], a->d[1]); + extract(l[1]); + muladd2(a->d[0], a->d[2]); + muladd(a->d[1], a->d[1]); + extract(l[2]); + muladd2(a->d[0], a->d[3]); + muladd2(a->d[1], a->d[2]); + extract(l[3]); + muladd2(a->d[1], a->d[3]); + muladd(a->d[2], a->d[2]); + extract(l[4]); + muladd2(a->d[2], a->d[3]); + extract(l[5]); + muladd_fast(a->d[3], a->d[3]); + extract_fast(l[6]); + VERIFY_CHECK(c1 == 0); + l[7] = c0; +#endif +} + +#undef sumadd +#undef sumadd_fast +#undef muladd +#undef muladd_fast +#undef muladd2 +#undef extract +#undef extract_fast + +static void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b) { + uint64_t l[8]; + secp256k1_scalar_mul_512(l, a, b); + secp256k1_scalar_reduce_512(r, l); +} + +static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n) { + int ret; + VERIFY_CHECK(n > 0); + VERIFY_CHECK(n < 16); + ret = r->d[0] & ((1 << n) - 1); + r->d[0] = (r->d[0] >> n) + (r->d[1] << (64 - n)); + r->d[1] = (r->d[1] >> n) + (r->d[2] << (64 - n)); + r->d[2] = (r->d[2] >> n) + (r->d[3] << (64 - n)); + r->d[3] = (r->d[3] >> n); + return ret; +} + +static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a) { + uint64_t l[8]; + secp256k1_scalar_sqr_512(l, a); + secp256k1_scalar_reduce_512(r, l); +} + +#ifdef USE_ENDOMORPHISM +static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a) { + r1->d[0] = a->d[0]; + r1->d[1] = a->d[1]; + r1->d[2] = 0; + r1->d[3] = 0; + r2->d[0] = a->d[2]; + r2->d[1] = a->d[3]; + r2->d[2] = 0; + r2->d[3] = 0; +} +#endif + +SECP256K1_INLINE static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b) { + return ((a->d[0] ^ b->d[0]) | (a->d[1] ^ b->d[1]) | (a->d[2] ^ b->d[2]) | (a->d[3] ^ b->d[3])) == 0; +} + +SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift) { + uint64_t l[8]; + unsigned int shiftlimbs; + unsigned int shiftlow; + unsigned int shifthigh; + VERIFY_CHECK(shift >= 256); + secp256k1_scalar_mul_512(l, a, b); + shiftlimbs = shift >> 6; + shiftlow = shift & 0x3F; + shifthigh = 64 - shiftlow; + r->d[0] = shift < 512 ? (l[0 + shiftlimbs] >> shiftlow | (shift < 448 && shiftlow ? (l[1 + shiftlimbs] << shifthigh) : 0)) : 0; + r->d[1] = shift < 448 ? (l[1 + shiftlimbs] >> shiftlow | (shift < 384 && shiftlow ? (l[2 + shiftlimbs] << shifthigh) : 0)) : 0; + r->d[2] = shift < 384 ? (l[2 + shiftlimbs] >> shiftlow | (shift < 320 && shiftlow ? (l[3 + shiftlimbs] << shifthigh) : 0)) : 0; + r->d[3] = shift < 320 ? (l[3 + shiftlimbs] >> shiftlow) : 0; + secp256k1_scalar_cadd_bit(r, 0, (l[(shift - 1) >> 6] >> ((shift - 1) & 0x3f)) & 1); +} + +#endif |