xIFO.h

00001  
00002  /**
00003  * @file    xifo.h
00004  * @brief   xifo circular buffer
00005  * @details xifo supplies object oriented circular buffer with 32 bit size elements. \n
00006  *                     To use either as FIFO (First In First Out) or as FILO (First In Last Out)
00007  *
00008  * @author    Jeroen Lodder
00009  * @date        April 2013
00010  * @version 2
00011  *
00012  * @{
00013  */
00014  
00015  /**
00016  *    Code has been tested on Cortex M0 (LPC1114)
00017  *  Performance table, number of core clocks
00018  *    Measured with a timer before and after
00019  *    r1 = timer->TC
00020  *        test_function 
00021  *  r2 = timer->TC
00022  *
00023  *  Function    Speed        Worst Case
00024  *
00025  *  write            69            71
00026  *  read_mr        59      59
00027  *  read_lr        63      70
00028  *  pop_mr        76      78
00029  *    pop_lr        45      45
00030  *
00031  */
00032 
00033 #ifndef _xifo_H_
00034 #define _xifo_H_
00035 
00036 #include <inttypes.h>
00037 
00038 #if defined(__arm__)  || defined(__DOXYGEN__)
00039 #pragma anon_unions                /**< Allow unnamed unions */
00040 #endif
00041 
00042 /**
00043  * @brief   Circular Buffer object.
00044  * @details This struct holds the object of a circular buffer
00045  */
00046 typedef struct  {
00047 /* Pointers: */
00048         uint32_t *startpool;  /**< @brief First element in pool */
00049         uint32_t *endpool;        /**< @brief Last element in pool */
00050         uint32_t *read;                /**< @brief Read pointer */
00051         uint32_t *write;            /**< @brief Write pointer */
00052 /* Variables: */
00053         uint32_t full;        /**< @brief Flag indicating buffer is full */
00054     uint32_t elementcount;/**< @brief Number of elements used */
00055         uint32_t size;                /**< @brief Size of buffer */
00056 /* Locally used in functions to prevent stack use: */
00057         /**< @brief union to prevent lvalue typecasting */  
00058         union {                         
00059             uint32_t temp;            /**< @brief temp variable and padding for even sized block */
00060             uint32_t *ptemp;         /**< @brief temp variable and padding for even sized block */
00061         };
00062 }xifo_t;
00063 
00064 /**
00065  * @brief   Circular Buffer memory pool type.
00066  */
00067 typedef unsigned int xifo_pool_t;
00068 
00069 #ifdef __cplusplus
00070 extern "C" {
00071 #endif
00072 /* xifo Common */
00073 void xifo_init(xifo_t *c, uint32_t size, uint32_t *startpool);
00074 void xifo_clear(xifo_t *c);
00075 uint32_t xifo_write(xifo_t *c, uint32_t data);
00076 /* FIFO use */
00077 uint32_t xifo_read_lr(xifo_t *c, uint32_t index);
00078 uint32_t xifo_pop_lr(xifo_t *c);
00079 /* LIFO use */
00080 uint32_t xifo_read_mr(xifo_t *c, uint32_t index);
00081 uint32_t xifo_pop_mr(xifo_t *c);
00082 /* Extractors */
00083 uint32_t xifo_get_size(xifo_t *c);
00084 uint32_t xifo_get_used(xifo_t *c);
00085 uint32_t xifo_get_full(xifo_t *c);
00086 uint32_t xifo_get_free(xifo_t *c);
00087 #ifdef __cplusplus
00088 }
00089 #endif
00090 #endif //_xifo_H_
00091 
00092 /** @} */