4 * Copyright (C) 2003,2004 Develer S.r.l. (http://www.develer.com/)
5 * Copyright (C) 2001 Bernardo Innocenti <bernie@develer.com>
11 * \author Bernardo Innocenti <bernie@develer.com>
13 * \brief General pourpose FIFO buffer implemented with a ring buffer
15 * \li \c begin punta al primo elemento del buffer,
16 * \li \c end punta all'ultimo elemento,
17 * \li \c head punta al prossimo elemento che verra' estratto,
18 * \li \c tail punta alla posizione successiva all'ultimo elemento inserito.
19 * \li quando uno dei due puntatori raggiunge @c end, viene resettato a @c begin.
23 * +-----------------------------------+
24 * | vuoto | dati validi | vuoto |
25 * +-----------------------------------+
31 * Il buffer e' VUOTO quando head e tail coincidono:
32 * \code head == tail \endcode
34 * Il buffer e' PIENO quando tail si trova immediatamente dietro a head:
35 * \code tail == head - 1 \endcode
37 * Il buffer e' PIENO anche quando tail e' posizionato
38 * sull'ultima posizione del buffer e head sulla prima:
39 * \code head == begin && tail == end \endcode
44 * Revision 1.1 2004/05/23 15:43:16 bernie
45 * Import mware modules.
47 * Revision 1.3 2004/05/22 17:55:58 rasky
48 * \samp non esiste in doxygen
50 * Revision 1.2 2004/04/27 11:13:29 rasky
51 * Spostate tutte le definizioni CPU-specific da compiler.h nel nuovo file cpu.h
53 * Revision 1.1 2004/04/21 17:38:25 rasky
56 * Revision 1.4 2004/03/24 15:37:03 bernie
57 * Remove Copyright messages from Doxygen output
59 * Revision 1.3 2004/03/18 18:11:07 bernie
60 * Add thread-safe FIFO handling macros
62 * Revision 1.2 2004/03/01 08:00:36 bernie
65 * Revision 1.1 2003/12/07 04:04:20 bernie
66 * Initial project_ks framework.
68 * Revision 1.1 2003/11/21 16:36:17 aleph
69 * Rename from fifo to fifobuf to avoid conflict with BSP fifo.h header
71 * Revision 1.1 2003/11/20 22:17:41 aleph
72 * Add fifo buffer used by serial
84 typedef struct FIFOBuffer
92 /* Public function prototypes */
93 void fifo_init(volatile FIFOBuffer *fb, unsigned char *buf, size_t size);
95 #pragma interrupt called
96 void fifo_push(volatile FIFOBuffer *fb, unsigned char c);
98 #pragma interrupt called
99 unsigned char fifo_pop(volatile FIFOBuffer *fb);
103 * Check whether the fifo is empty
105 * \note Calling fifo_isempty() is safe while a concurrent
106 * execution context is calling fifo_push() or fifo_pop()
107 * only if the CPU can atomically update a pointer.
109 #define fifo_isempty(fb) ((fb)->head == (fb)->tail)
112 * Check whether the fifo is full
114 * \note Calling fifo_isfull() is safe while a concurrent
115 * execution context is calling fifo_pop() and the
116 * CPU can update a pointer atomically.
117 * It is NOT safe when the other context calls
119 * This limitation is not usually problematic in a
120 * consumer/producer scenario because the
121 * fifo_isfull() and fifo_push() are usually called
122 * in the producer context.
124 #define fifo_isfull(fb) \
125 ((((fb)->head == (fb)->begin) && ((fb)->tail == (fb)->end)) \
126 || ((fb)->tail == (fb)->head - 1))
129 * Make the fifo empty, discarding all its current contents.
131 #define fifo_flush(fb) ((fb)->head = (fb)->tail)
133 #if !defined(__AVR__)
135 /* No tricks needed on 16/32bit CPUs */
136 # define fifo_isempty_locked(fb) fifo_isempty((fb))
140 INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb);
141 INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb)
146 DISABLE_IRQSAVE(_flags);
147 _result = fifo_isempty(_fb);
148 ENABLE_IRQRESTORE(_flags);
153 #endif /* !__AVR__ */
156 * Thread safe version of fifo_isfull()
158 INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb);
159 INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb)
164 DISABLE_IRQSAVE(_flags);
165 _result = fifo_isfull(_fb);
166 ENABLE_IRQRESTORE(_flags);
171 #endif /* MWARE_FIFOBUF_H */