-/*!
+/**
* \file
* <!--
- * Copyright (C) 2003,2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright (C) 2001 Bernardo Innocenti <bernie@develer.com>
- * All Rights Reserved.
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2001 Bernardo Innocenti <bernie@develer.com>
+ *
* -->
*
* \version $Id$
*
* \brief General pourpose FIFO buffer implemented with a ring buffer
*
- * \li \c begin punta al primo elemento del buffer,
- * \li \c end punta all'ultimo elemento,
- * \li \c head punta al prossimo elemento che verra' estratto,
- * \li \c tail punta alla posizione successiva all'ultimo elemento inserito.
- * \li quando uno dei due puntatori raggiunge @c end, viene resettato a @c begin.
+ * \li \c begin points to the first buffer element;
+ * \li \c end points to the last buffer element (unlike the STL convention);
+ * \li \c head points to the element to be extracted next;
+ * \li \c tail points to the location following the last insertion;
+ * \li when any of the pointers advances beyond \c end, it is reset
+ * back to \c begin.
*
- * <pre>
+ * \code
*
* +-----------------------------------+
- * | vuoto | dati validi | vuoto |
+ * | empty | valid data | empty |
* +-----------------------------------+
* ^ ^ ^ ^
* begin head tail end
*
- * </pre>
+ * \endcode
*
- * Il buffer e' VUOTO quando head e tail coincidono:
+ * The buffer is EMPTY when \c head and \c tail point to the same location:
* \code head == tail \endcode
*
- * Il buffer e' PIENO quando tail si trova immediatamente dietro a head:
+ * The buffer is FULL when \c tail points to the location immediately
+ * after \c head:
* \code tail == head - 1 \endcode
*
- * Il buffer e' PIENO anche quando tail e' posizionato
- * sull'ultima posizione del buffer e head sulla prima:
+ * The buffer is also FULL when \c tail points to the last buffer
+ * location and head points to the first one:
* \code head == begin && tail == end \endcode
*/
-/*
- * $Log$
- * Revision 1.1 2004/05/23 15:43:16 bernie
- * Import mware modules.
- *
- * Revision 1.3 2004/05/22 17:55:58 rasky
- * \samp non esiste in doxygen
- *
- * Revision 1.2 2004/04/27 11:13:29 rasky
- * Spostate tutte le definizioni CPU-specific da compiler.h nel nuovo file cpu.h
- *
- * Revision 1.1 2004/04/21 17:38:25 rasky
- * New application
- *
- * Revision 1.4 2004/03/24 15:37:03 bernie
- * Remove Copyright messages from Doxygen output
- *
- * Revision 1.3 2004/03/18 18:11:07 bernie
- * Add thread-safe FIFO handling macros
- *
- * Revision 1.2 2004/03/01 08:00:36 bernie
- * Fixes for Doxygen
- *
- * Revision 1.1 2003/12/07 04:04:20 bernie
- * Initial project_ks framework.
- *
- * Revision 1.1 2003/11/21 16:36:17 aleph
- * Rename from fifo to fifobuf to avoid conflict with BSP fifo.h header
- *
- * Revision 1.1 2003/11/20 22:17:41 aleph
- * Add fifo buffer used by serial
- *
- */
-
#ifndef MWARE_FIFO_H
#define MWARE_FIFO_H
-#include "cpu.h"
-#ifndef COMPILER_H
-#include "compiler.h"
-#endif
+#include <cpu/types.h>
+#include <cpu/irq.h>
+#include <cfg/debug.h>
typedef struct FIFOBuffer
{
- unsigned char *head;
- unsigned char *tail;
+ unsigned char * volatile head;
+ unsigned char * volatile tail;
unsigned char *begin;
unsigned char *end;
} FIFOBuffer;
-/* Public function prototypes */
-void fifo_init(volatile FIFOBuffer *fb, unsigned char *buf, size_t size);
-#pragma interrupt called
-void fifo_push(volatile FIFOBuffer *fb, unsigned char c);
+#define ASSERT_VALID_FIFO(fifo) \
+ ATOMIC( \
+ ASSERT((fifo)->head >= (fifo)->begin); \
+ ASSERT((fifo)->head <= (fifo)->end); \
+ ASSERT((fifo)->tail >= (fifo)->begin); \
+ ASSERT((fifo)->tail <= (fifo)->end); \
+ )
-#pragma interrupt called
-unsigned char fifo_pop(volatile FIFOBuffer *fb);
-
-/*!
+/**
* Check whether the fifo is empty
*
* \note Calling fifo_isempty() is safe while a concurrent
* execution context is calling fifo_push() or fifo_pop()
- * only if the CPU can atomically update a pointer.
+ * only if the CPU can atomically update a pointer
+ * (which the AVR and other 8-bit processors can't do).
+ *
+ * \sa fifo_isempty_locked
*/
-#define fifo_isempty(fb) ((fb)->head == (fb)->tail)
+INLINE bool fifo_isempty(const FIFOBuffer *fb)
+{
+ //ASSERT_VALID_FIFO(fb);
+ return fb->head == fb->tail;
+}
+
-/*!
+/**
* Check whether the fifo is full
*
* \note Calling fifo_isfull() is safe while a concurrent
* fifo_isfull() and fifo_push() are usually called
* in the producer context.
*/
-#define fifo_isfull(fb) \
- ((((fb)->head == (fb)->begin) && ((fb)->tail == (fb)->end)) \
- || ((fb)->tail == (fb)->head - 1))
+INLINE bool fifo_isfull(const FIFOBuffer *fb)
+{
+ //ASSERT_VALID_FIFO(fb);
+ return
+ ((fb->head == fb->begin) && (fb->tail == fb->end))
+ || (fb->tail == fb->head - 1);
+}
+
+
+/**
+ * Push a character on the fifo buffer.
+ *
+ * \note Calling \c fifo_push() on a full buffer is undefined.
+ * The caller must make sure the buffer has at least
+ * one free slot before calling this function.
+ *
+ * \note It is safe to call fifo_pop() and fifo_push() from
+ * concurrent contexts, unless the CPU can't update
+ * a pointer atomically (which the AVR and other 8-bit
+ * processors can't do).
+ *
+ * \sa fifo_push_locked
+ */
+INLINE void fifo_push(FIFOBuffer *fb, unsigned char c)
+{
+#ifdef __MWERKS__
+#pragma interrupt called
+#endif
+ //ASSERT_VALID_FIFO(fb);
+
+ /* Write at tail position */
+ *(fb->tail) = c;
+
+ if (UNLIKELY(fb->tail == fb->end))
+ /* wrap tail around */
+ fb->tail = fb->begin;
+ else
+ /* Move tail forward */
+ fb->tail++;
+}
+
+
+/**
+ * Pop a character from the fifo buffer.
+ *
+ * \note Calling \c fifo_pop() on an empty buffer is undefined.
+ * The caller must make sure the buffer contains at least
+ * one character before calling this function.
+ *
+ * \note It is safe to call fifo_pop() and fifo_push() from
+ * concurrent contexts.
+ */
+INLINE unsigned char fifo_pop(FIFOBuffer *fb)
+{
+#ifdef __MWERKS__
+#pragma interrupt called
+#endif
+ //ASSERT_VALID_FIFO(fb);
+
+ if (UNLIKELY(fb->head == fb->end))
+ {
+ /* wrap head around */
+ fb->head = fb->begin;
+ return *(fb->end);
+ }
+ else
+ /* move head forward */
+ return *(fb->head++);
+}
+
-/*!
+/**
* Make the fifo empty, discarding all its current contents.
*/
-#define fifo_flush(fb) ((fb)->head = (fb)->tail)
+INLINE void fifo_flush(FIFOBuffer *fb)
+{
+ //ASSERT_VALID_FIFO(fb);
+ fb->head = fb->tail;
+}
+
-#if !defined(__AVR__)
+#if CPU_REG_BITS >= CPU_BITS_PER_PTR
- /* No tricks needed on 16/32bit CPUs */
-# define fifo_isempty_locked(fb) fifo_isempty((fb))
+ /*
+ * 16/32bit CPUs that can update a pointer with a single write
+ * operation, no need to disable interrupts.
+ */
+ #define fifo_isempty_locked(fb) fifo_isempty((fb))
+ #define fifo_push_locked(fb, c) fifo_push((fb), (c))
+ #define fifo_pop_locked(fb) fifo_pop((fb))
+ #define fifo_flush_locked(fb) fifo_flush((fb))
-#else /* !__AVR__ */
+#else /* CPU_REG_BITS < CPU_BITS_PER_PTR */
- INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb);
- INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb)
+ /**
+ * Similar to fifo_isempty(), but with stronger guarantees for
+ * concurrent access between user and interrupt code.
+ *
+ * \note This is actually only needed for 8-bit processors.
+ *
+ * \sa fifo_isempty()
+ */
+ INLINE bool fifo_isempty_locked(const FIFOBuffer *fb)
{
- bool _result;
- cpuflags_t _flags;
+ bool result;
+ ATOMIC(result = fifo_isempty(fb));
+ return result;
+ }
- DISABLE_IRQSAVE(_flags);
- _result = fifo_isempty(_fb);
- ENABLE_IRQRESTORE(_flags);
- return _result;
+ /**
+ * Similar to fifo_push(), but with stronger guarantees for
+ * concurrent access between user and interrupt code.
+ *
+ * \note This is actually only needed for 8-bit processors.
+ *
+ * \sa fifo_push()
+ */
+ INLINE void fifo_push_locked(FIFOBuffer *fb, unsigned char c)
+ {
+ ATOMIC(fifo_push(fb, c));
+ }
+
+ /* Probably not really needed, but hard to prove. */
+ INLINE unsigned char fifo_pop_locked(FIFOBuffer *fb)
+ {
+ unsigned char c;
+ ATOMIC(c = fifo_pop(fb));
+ return c;
+ }
+
+ /**
+ * Similar to fifo_flush(), but with stronger guarantees for
+ * concurrent access between user and interrupt code.
+ *
+ * \note This is actually only needed for 8-bit processors.
+ *
+ * \sa fifo_flush()
+ */
+ INLINE void fifo_flush_locked(FIFOBuffer *fb)
+ {
+ ATOMIC(fifo_flush(fb));
}
-#endif /* !__AVR__ */
+#endif /* CPU_REG_BITS < BITS_PER_PTR */
-/*!
+
+/**
* Thread safe version of fifo_isfull()
*/
-INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb);
-INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb)
+INLINE bool fifo_isfull_locked(const FIFOBuffer *_fb)
{
- bool _result;
- cpuflags_t _flags;
+ bool result;
+ ATOMIC(result = fifo_isfull(_fb));
+ return result;
+}
+
- DISABLE_IRQSAVE(_flags);
- _result = fifo_isfull(_fb);
- ENABLE_IRQRESTORE(_flags);
+/**
+ * FIFO Initialization.
+ */
+INLINE void fifo_init(FIFOBuffer *fb, unsigned char *buf, size_t size)
+{
+ /* FIFO buffers have a known bug with 1-byte buffers. */
+ ASSERT(size > 1);
- return _result;
+ fb->head = fb->tail = fb->begin = buf;
+ fb->end = buf + size - 1;
}
-#endif /* MWARE_FIFOBUF_H */
+
+#if 0
+
+/*
+ * UNTESTED: if uncommented, to be moved in fifobuf.c
+ */
+void fifo_pushblock(FIFOBuffer *fb, unsigned char *block, size_t len)
+{
+ size_t freelen;
+
+ /* Se c'e' spazio da tail alla fine del buffer */
+ if (fb->tail >= fb->head)
+ {
+ freelen = fb->end - fb->tail + 1;
+
+ /* C'e' abbastanza spazio per scrivere tutto il blocco? */
+ if (freelen < len)
+ {
+ /* Scrivi quello che entra fino alla fine del buffer */
+ memcpy(fb->tail, block, freelen);
+ block += freelen;
+ len -= freelen;
+ fb->tail = fb->begin;
+ }
+ else
+ {
+ /* Scrivi tutto il blocco */
+ memcpy(fb->tail, block, len);
+ fb->tail += len;
+ return;
+ }
+ }
+
+ for(;;)
+ {
+ while (!(freelen = fb->head - fb->tail - 1))
+ Delay(FIFO_POLLDELAY);
+
+ /* C'e' abbastanza spazio per scrivere tutto il blocco? */
+ if (freelen < len)
+ {
+ /* Scrivi quello che entra fino alla fine del buffer */
+ memcpy(fb->tail, block, freelen);
+ block += freelen;
+ len -= freelen;
+ fb->tail += freelen;
+ }
+ else
+ {
+ /* Scrivi tutto il blocco */
+ memcpy(fb->tail, block, len);
+ fb->tail += len;
+ return;
+ }
+ }
+}
+#endif
+
+#endif /* MWARE_FIFO_H */
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