4 * Copyright 2003,2004 Develer S.r.l. (http://www.develer.com/)
5 * Copyright 2001 Bernardo Innocenti <bernie@develer.com>
6 * This file is part of DevLib - See devlib/README for information.
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 1.2 2004/06/03 11:27:09 bernie
45 * Add dual-license information.
47 * Revision 1.1 2004/05/23 15:43:16 bernie
48 * Import mware modules.
50 * Revision 1.3 2004/05/22 17:55:58 rasky
51 * \samp non esiste in doxygen
53 * Revision 1.2 2004/04/27 11:13:29 rasky
54 * Spostate tutte le definizioni CPU-specific da compiler.h nel nuovo file cpu.h
56 * Revision 1.1 2004/04/21 17:38:25 rasky
59 * Revision 1.4 2004/03/24 15:37:03 bernie
60 * Remove Copyright messages from Doxygen output
62 * Revision 1.3 2004/03/18 18:11:07 bernie
63 * Add thread-safe FIFO handling macros
65 * Revision 1.2 2004/03/01 08:00:36 bernie
68 * Revision 1.1 2003/12/07 04:04:20 bernie
69 * Initial project_ks framework.
71 * Revision 1.1 2003/11/21 16:36:17 aleph
72 * Rename from fifo to fifobuf to avoid conflict with BSP fifo.h header
74 * Revision 1.1 2003/11/20 22:17:41 aleph
75 * Add fifo buffer used by serial
87 typedef struct FIFOBuffer
95 /* Public function prototypes */
96 void fifo_init(volatile FIFOBuffer *fb, unsigned char *buf, size_t size);
98 #pragma interrupt called
99 void fifo_push(volatile FIFOBuffer *fb, unsigned char c);
101 #pragma interrupt called
102 unsigned char fifo_pop(volatile FIFOBuffer *fb);
106 * Check whether the fifo is empty
108 * \note Calling fifo_isempty() is safe while a concurrent
109 * execution context is calling fifo_push() or fifo_pop()
110 * only if the CPU can atomically update a pointer.
112 #define fifo_isempty(fb) ((fb)->head == (fb)->tail)
115 * Check whether the fifo is full
117 * \note Calling fifo_isfull() is safe while a concurrent
118 * execution context is calling fifo_pop() and the
119 * CPU can update a pointer atomically.
120 * It is NOT safe when the other context calls
122 * This limitation is not usually problematic in a
123 * consumer/producer scenario because the
124 * fifo_isfull() and fifo_push() are usually called
125 * in the producer context.
127 #define fifo_isfull(fb) \
128 ((((fb)->head == (fb)->begin) && ((fb)->tail == (fb)->end)) \
129 || ((fb)->tail == (fb)->head - 1))
132 * Make the fifo empty, discarding all its current contents.
134 #define fifo_flush(fb) ((fb)->head = (fb)->tail)
136 #if !defined(__AVR__)
138 /* No tricks needed on 16/32bit CPUs */
139 # define fifo_isempty_locked(fb) fifo_isempty((fb))
143 INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb);
144 INLINE bool fifo_isempty_locked(const volatile FIFOBuffer *_fb)
149 DISABLE_IRQSAVE(_flags);
150 _result = fifo_isempty(_fb);
151 ENABLE_IRQRESTORE(_flags);
156 #endif /* !__AVR__ */
159 * Thread safe version of fifo_isfull()
161 INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb);
162 INLINE bool fifo_isfull_locked(const volatile FIFOBuffer *_fb)
167 DISABLE_IRQSAVE(_flags);
168 _result = fifo_isfull(_fb);
169 ENABLE_IRQRESTORE(_flags);
174 #endif /* MWARE_FIFOBUF_H */