+++ /dev/null
-/*!
- * \file
- * <!--
- * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 2001 Bernardo Innocenti <bernie@develer.com>
- * This file is part of DevLib - See devlib/README for information.
- * -->
- *
- * \version $Id$
- *
- * \author Bernardo Innocenti <bernie@develer.com>
- *
- * \brief General pourpose FIFO buffer implemented with a ring buffer
- *
- * \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.
- *
- * \code
- *
- * +-----------------------------------+
- * | empty | valid data | empty |
- * +-----------------------------------+
- * ^ ^ ^ ^
- * begin head tail end
- *
- * \endcode
- *
- * The buffer is EMPTY when \c head and \c tail point to the same location:
- * \code head == tail \endcode
- *
- * The buffer is FULL when \c tail points to the location immediately
- * after \c head:
- * \code tail == head - 1 \endcode
- *
- * 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 1.12 2004/08/02 20:20:29 aleph
- * Merge from project_ks
- *
- * Revision 1.11 2004/07/30 14:15:53 rasky
- * Nuovo supporto unificato per detect della CPU
- *
- * Revision 1.10 2004/07/29 22:57:09 bernie
- * Doxygen fix.
- *
- * Revision 1.9 2004/07/20 23:54:27 bernie
- * fifo_flush_locked(): New function;
- * Revamp documentation.
- *
- * Revision 1.8 2004/07/20 23:47:39 bernie
- * Finally remove redundant protos.
- *
- * Revision 1.7 2004/07/20 23:46:29 bernie
- * Finally remove redundant protos.
- *
- * Revision 1.6 2004/06/06 17:18:04 bernie
- * Remove redundant declaration of fifo_isempty_locked().
- *
- * Revision 1.5 2004/06/06 16:50:35 bernie
- * Import fixes for race conditions from project_ks.
- *
- * Revision 1.4 2004/06/06 16:11:17 bernie
- * Protect MetroWerks specific pragmas with #ifdef's
- */
-
-#ifndef MWARE_FIFO_H
-#define MWARE_FIFO_H
-
-#include "cpu.h"
-
-typedef struct FIFOBuffer
-{
- unsigned char * volatile head;
- unsigned char * volatile tail;
- unsigned char *begin;
- unsigned char *end;
-} FIFOBuffer;
-
-
-/*!
- * 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
- * (which the AVR and other 8-bit processors can't do).
- *
- * \sa fifo_isempty_locked
- */
-INLINE bool fifo_isempty(const FIFOBuffer *fb)
-{
- return fb->head == fb->tail;
-}
-
-
-/*!
- * Check whether the fifo is full
- *
- * \note Calling fifo_isfull() is safe while a concurrent
- * execution context is calling fifo_pop() and the
- * CPU can update a pointer atomically.
- * It is NOT safe when the other context calls
- * fifo_push().
- * This limitation is not usually problematic in a
- * consumer/producer scenario because the
- * fifo_isfull() and fifo_push() are usually called
- * in the producer context.
- */
-INLINE bool fifo_isfull(const FIFOBuffer *fb)
-{
- return
- ((fb->head == fb->begin) && (fb->tail == fb->end))
- || (fb->tail == fb->head - 1);
-}
-
-
-/*!
- * Pop a character from 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
- /* Write at tail position */
- *(fb->tail) = c;
-
- if (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
- if (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.
- */
-INLINE void fifo_flush(FIFOBuffer *fb)
-{
- fb->head = fb->tail;
-}
-
-
-#if !CPU_AVR
-
- /* No tricks needed on 16/32bit CPUs */
-# define fifo_isempty_locked(fb) fifo_isempty((fb))
-# define fifo_push_locked(fb, c) fifo_push((fb), (c))
-# define fifo_flush_locked(fb) fifo_flush((fb))
-
-#else /* !CPU_AVR */
-
- /*!
- * 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;
-
- 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)
- {
- cpuflags_t flags;
- DISABLE_IRQSAVE(flags);
- fifo_push(fb, c);
- ENABLE_IRQRESTORE(flags);
- }
-
- /*!
- * 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)
- {
- cpuflags_t flags;
- DISABLE_IRQSAVE(flags);
- fifo_flush(fb);
- ENABLE_IRQRESTORE(flags);
- }
-
-#endif /* !CPU_AVR */
-
-
-/*!
- * Thread safe version of fifo_isfull()
- */
-INLINE bool fifo_isfull_locked(const FIFOBuffer *_fb)
-{
- bool _result;
- cpuflags_t _flags;
-
- DISABLE_IRQSAVE(_flags);
- _result = fifo_isfull(_fb);
- ENABLE_IRQRESTORE(_flags);
-
- return _result;
-}
-
-
-/*!
- * FIFO Initialization.
- */
-INLINE void fifo_init(FIFOBuffer *fb, unsigned char *buf, size_t size)
-{
- fb->head = fb->tail = fb->begin = buf;
- fb->end = buf + size - 1;
-}
-
-
-#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 */
-
projects / bertos.git / blobdiff