/*

 * Copyright (c) 2013-2017, Intel Corporation

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *  * Neither the name of Intel Corporation nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#include "pt_retstack.h"

#include "intel-pt.h"

void pt_retstack_init(struct pt_retstack *retstack)

{

	if (!retstack)

		return;

	retstack->top = 0;

	retstack->bottom = 0;

}

int pt_retstack_is_empty(const struct pt_retstack *retstack)

{

	if (!retstack)

		return -pte_invalid;

	return (retstack->top == retstack->bottom ? 1 : 0);

}

int pt_retstack_pop(struct pt_retstack *retstack, uint64_t *ip)

{

	uint8_t top;

	if (!retstack)

		return -pte_invalid;

	top = retstack->top;

	if (top == retstack->bottom)

		return -pte_retstack_empty;

	top = (!top ? pt_retstack_size : top - 1);

	retstack->top = top;

	if (ip)

		*ip = retstack->stack[top];

	return 0;

}

int pt_retstack_push(struct pt_retstack *retstack, uint64_t ip)

{

	uint8_t top, bottom;

	if (!retstack)

		return -pte_invalid;

	top = retstack->top;

	bottom = retstack->bottom;

	retstack->stack[top] = ip;

	top = (top == pt_retstack_size ? 0 : top + 1);

	if (bottom == top)

		bottom = (bottom == pt_retstack_size ? 0 : bottom + 1);

	retstack->top = top;

	retstack->bottom = bottom;

	return 0;

}