/* Copyright (c) 2018, Google Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

#ifndef OPENSSL_HEADER_HRSS_INTERNAL_H
#define OPENSSL_HEADER_HRSS_INTERNAL_H

#include <openssl/base.h>
#include "../internal.h"
#include "../fipsmodule/cpucap/internal.h"

#if defined(__cplusplus)
extern "C" {
#endif


#define N 701
#define BITS_PER_WORD (sizeof(crypto_word_t) * 8)
#define WORDS_PER_POLY ((N + BITS_PER_WORD - 1) / BITS_PER_WORD)
#define BITS_IN_LAST_WORD (N % BITS_PER_WORD)

struct poly2 {
  crypto_word_t v[WORDS_PER_POLY];
};

struct poly3 {
  struct poly2 s, a;
};

OPENSSL_EXPORT void HRSS_poly3_mul(struct poly3 *out, const struct poly3 *x,
                                   const struct poly3 *y);
OPENSSL_EXPORT void HRSS_poly3_invert(struct poly3 *out,
                                      const struct poly3 *in);

// On x86-64, we can use the AVX2 code from [HRSS]. (The authors have given
// explicit permission for this and signed a CLA.) However it's 57KB of object
// code, so it's not used if |OPENSSL_SMALL| is defined.
#if !defined(OPENSSL_NO_ASM) && !defined(OPENSSL_SMALL) && \
    defined(OPENSSL_X86_64) && defined(OPENSSL_LINUX) && \
    !defined(MY_ASSEMBLER_IS_TOO_OLD_FOR_AVX)
#define POLY_RQ_MUL_ASM
// POLY_MUL_RQ_SCRATCH_SPACE is the number of bytes of scratch space needed
// by the assembly function poly_Rq_mul.
#define POLY_MUL_RQ_SCRATCH_SPACE (6144 + 6144 + 12288 + 512 + 9408 + 32)

// poly_Rq_mul is defined in assembly. Inputs and outputs must be 16-byte-
// aligned.
extern void poly_Rq_mul(
    uint16_t r[N + 3], const uint16_t a[N + 3], const uint16_t b[N + 3],
    // The following should be `scratch[POLY_MUL_RQ_SCRATCH_SPACE]` but
    // GCC 11.1 has a bug with unions that breaks that.
    uint8_t scratch[]);
#endif


#if defined(__cplusplus)
}  // extern "C"
#endif

#endif  // !OPENSSL_HEADER_HRSS_INTERNAL_H