bfifo.c

Jan 04, 2007 1. Add SPI support, see spi.h and spi.c 2. Add driver.h 3. Modified keyboard modu

/**
 * Copyright (c) 2006-2008 iWESUN (ShenZhen) Inf.
 * All rights reserved. 
 * 
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * This file is part of the AvrcX MTOS
 * 
 * Author: Winter Hu  <[e-mail]>
 * Create: Nov 26, 2006
 *
 */

#include "bfifo.h"

/**
 * Test whether the fifo is fully
 *
 * @param ByteFifo*, The pointer to the ByteFifo
 * @return unsigned char, 1: fully, 0: not fully
 */
unsigned char is_fully(ByteFifo* pFifo){
  return (pFifo->status & FIFO_IS_FULLY) ? TRUE : FALSE;

}

/**
 * Test whether the fifo is empty
 *
 * @param ByteFifo*, The pointer to the ByteFifo
 * @return unsigned char, 1: empty, 0: not empty
 */
unsigned char is_empty(ByteFifo* pFifo){
  return (pFifo->status & FIFO_IS_EMPTY) ? TRUE : FALSE;
}

/**
 * Gets the first byte from the fifo front
 * This method could be blocked if fifo is empty in user mode.
 *
 * @param ByteFifo*, The pointer to the ByteFifo
 * @retrun unsigned char, the byte pop from fifo front
 */ 
unsigned char get_byte(ByteFifo* pFifo){
  
  P(&(pFifo->sync->not_empty));
  
  P(&(pFifo->sync->mutex));

  unsigned char b = fifo_getbyte(pFifo);

  V(&(pFifo->sync->mutex));

  V(&(pFifo->sync->not_fully));

  return b;
}

/**
 * Puts a byte to the fifo tail
 * This method could be blocked if fifo is fully in user mode.
 * 
 * @param ByteFifo*, The pointer to the ByteFifo
 * @param unsigned char, The byte need puts into the queue
 */
void put_byte(ByteFifo* pFifo, unsigned char b){

  P(&(pFifo->sync->not_fully));

  P(&(pFifo->sync->mutex));
  
  fifo_putbyte(pFifo, b);

  V(&(pFifo->sync->mutex));

  V(&(pFifo->sync->not_empty));

}

/**
 * Get a byte from byte fifo
 * Return -1 if fifo is empty
 *
 * @param ByteFifo*, The pointer to the fifo
 * @return int, the data. -1 means fifo is empty
 */
int fifo_getbyte(ByteFifo* pFifo){

  if (pFifo->status & FIFO_IS_EMPTY) return -1;

  int b = *(pFifo->buffer+pFifo->readps);
  
  pFifo->readps++;
  pFifo->readps = (pFifo->readps >= pFifo->mxsize) ? 0 : pFifo->readps;

  if (pFifo->readps == pFifo->writps){
    pFifo->status |= FIFO_IS_EMPTY;
  }else{
    pFifo->status &= ~FIFO_IS_FULLY;
  }
  
  return b;
}

/**
 * Put a byte to byte fifo
 * Return -1 if fifo is fully
 *
 * @param ByteFifo*, The pointer to the fifo
 * @param unsigned char, the byte need to put
 * @return int, the byte had put into fifo, -1 means fifo is fully
 */
int fifo_putbyte(ByteFifo* pFifo, unsigned char b){

  if (pFifo->status & FIFO_IS_FULLY) return -1;

  *(pFifo->buffer+pFifo->writps) = b;

  pFifo->writps++;
  pFifo->writps = (pFifo->writps >= pFifo->mxsize) ? 0 : pFifo->writps;

  if (pFifo->writps == pFifo->readps){
    pFifo->status |= FIFO_IS_FULLY;
  }else{
    pFifo->status &= ~FIFO_IS_EMPTY;
  }

  return (int) b;
}