/****************************************************************************
 * common/up_irq.c
 *
 *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. Neither the name NuttX 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.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>

#include <nuttx/arch.h>
#include <nuttx/irq.h>

#include "up_internal.h"

/****************************************************************************
 * Private Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: irqsave
 *
 * Description:
 *   Disable all interrupts; return previous interrupt state
 *
 ****************************************************************************/

irqstate_t irqsave(void) __naked
{
  _asm
	ld	a, i		; AF Carry bit holds interrupt state
	di			; Interrupts are disabled
	push	af		; Return AF in HL
	pop	hl		;
	ret			;
  _endasm;
}

/****************************************************************************
 * Name: irqrestore
 *
 * Description:
 *   Restore previous interrupt state
 *
 ****************************************************************************/

void irqrestore(irqstate_t flags) __naked
{
  _asm
	di			; Assume disabled
	pop	hl		; HL = return address
	pop	af		; AF Carry bit hold interrupt state
	jr	nc, statedisable
	ei
statedisable:
	push	af		; Restore stack
	push	hl		;
	ret			; and return
  _endasm;
}