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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/crypto/libecc/src/fp/fp_add.c
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/*

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 *  Copyright (C) 2017 - This file is part of libecc project

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 *

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 *  Authors:

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 *      Ryad BENADJILA <[email protected]>

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 *      Arnaud EBALARD <[email protected]>

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 *      Jean-Pierre FLORI <[email protected]>

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 *

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 *  Contributors:

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 *      Nicolas VIVET <[email protected]>

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 *      Karim KHALFALLAH <[email protected]>

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 *

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 *  This software is licensed under a dual BSD and GPL v2 license.

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 *  See LICENSE file at the root folder of the project.

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 */

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#include <libecc/fp/fp_add.h>

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#include <libecc/nn/nn_add.h>

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/*

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 * Compute out = in1 + in2 mod p. 'out' parameter must have been initialized

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 * by the caller. Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_add(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	int ret, cmp;

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	ret = fp_check_initialized(out); EG(ret, err);

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	ret = fp_check_initialized(in1); EG(ret, err);

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	ret = fp_check_initialized(in2); EG(ret, err);

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	MUST_HAVE(((&(in1->ctx->p)) == (&(in2->ctx->p))), ret, err);

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	MUST_HAVE(((&(in1->ctx->p)) == (&(out->ctx->p))), ret, err);

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	FORCE_USED_VAR(cmp); /* silence warning when macro results in nothing */

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	SHOULD_HAVE(!nn_cmp(&in1->fp_val, &(in1->ctx->p), &cmp) && (cmp < 0), ret, err);

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	SHOULD_HAVE(!nn_cmp(&in2->fp_val, &(in2->ctx->p), &cmp) && (cmp < 0), ret, err);

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	ret = nn_mod_add(&(out->fp_val), &(in1->fp_val),

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			 &(in2->fp_val), &(in1->ctx->p));

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err:

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	return ret;

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}

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/*

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 * Compute out = in + 1 mod p. 'out' parameter must have been initialized

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 * by the caller. Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_inc(fp_t out, fp_src_t in)

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{

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	int ret, cmp;

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	ret = fp_check_initialized(in); EG(ret, err);

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	ret = fp_check_initialized(out); EG(ret, err);

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	MUST_HAVE(((&(in->ctx->p)) == (&(out->ctx->p))), ret, err);

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	FORCE_USED_VAR(cmp); /* silence warning when macro results in nothing */

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	SHOULD_HAVE(!nn_cmp(&in->fp_val, &(in->ctx->p), &cmp) && (cmp < 0), ret, err);

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	ret = nn_mod_inc(&(out->fp_val), &(in->fp_val), &(in->ctx->p));

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err:

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	return ret;

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}

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/*

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 * Compute out = in1 - in2 mod p. 'out' parameter must have been initialized

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 * by the caller. Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_sub(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	int ret, cmp;

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	ret = fp_check_initialized(out); EG(ret, err);

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	ret = fp_check_initialized(in1); EG(ret, err);

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	ret = fp_check_initialized(in2); EG(ret, err);

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	MUST_HAVE(((&(in1->ctx->p)) == (&(in2->ctx->p))), ret, err);

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	MUST_HAVE(((&(in1->ctx->p)) == (&(out->ctx->p))), ret, err);

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	FORCE_USED_VAR(cmp); /* silence warning when macro results in nothing */

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	SHOULD_HAVE(!nn_cmp(&in1->fp_val, &(in1->ctx->p), &cmp) && (cmp < 0), ret, err);

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	SHOULD_HAVE(!nn_cmp(&in2->fp_val, &(in2->ctx->p), &cmp) && (cmp < 0), ret, err);

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	ret = nn_mod_sub(&(out->fp_val), &(in1->fp_val),

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			 &(in2->fp_val), &(in1->ctx->p));

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err:

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	return ret;

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}

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/*

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 * Compute out = in - 1 mod p. 'out' parameter must have been initialized

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 * by the caller. Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_dec(fp_t out, fp_src_t in)

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{

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	int ret, cmp;

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	ret = fp_check_initialized(out); EG(ret, err);

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	ret = fp_check_initialized(in); EG(ret, err);

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	MUST_HAVE(((&(in->ctx->p)) == (&(out->ctx->p))), ret, err);

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	FORCE_USED_VAR(cmp); /* silence warning when macro results in nothing */

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	SHOULD_HAVE(!nn_cmp(&in->fp_val, &(in->ctx->p), &cmp) && (cmp < 0), ret, err);

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	ret = nn_mod_dec(&(out->fp_val), &(in->fp_val), &(in->ctx->p));

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err:

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	return ret;

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}

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/*

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 * Compute out = -in mod p = (p - in) mod p. 'out' parameter must have been

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 * initialized by the caller. Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_neg(fp_t out, fp_src_t in)

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{

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	int ret, cmp;

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	ret = fp_check_initialized(in); EG(ret, err);

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	ret = fp_check_initialized(out); EG(ret, err);

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	MUST_HAVE(((&(in->ctx->p)) == (&(out->ctx->p))), ret, err);

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	FORCE_USED_VAR(cmp); /* silence warning when macro results in nothing */

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	SHOULD_HAVE(!nn_cmp(&in->fp_val, &(in->ctx->p), &cmp) && (cmp < 0), ret, err);

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	ret = nn_sub(&(out->fp_val), &(in->ctx->p), &(in->fp_val));

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err:

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	return ret;

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}

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