mware/pgm.h

   1 /*!
   2  * \file
   3  * <!--
   4  * Copyright 2004, 2005 Develer S.r.l. (http://www.develer.com/)
   5  * Copyright 2004 Giovanni Bajo
   6  * This file is part of DevLib - See README.devlib for information.
   7  * -->
   8  *
   9  * \brief Support for reading program memory on Harvard architectures.
  10  *
  11  * Support is currently provided for AVR microcontrollers only.
  12  *
  13  * These macros allow building code twice, with and without
  14  * pgm support (e.g.: strcpy() and strcpy_P()).
  15  *
  16  * Set the _PROGMEM predefine to compile in conditional
  17  * program-memory support.
  18  *
  19  *
  20  * \note This module contains code ripped out from avr-libc,
  21  *       which is distributed under a 3-clause BSD license.
  22  */
  23 #ifndef MWARE_PGM_H
  24 #define MWARE_PGM_H
  25
  26 #include <cpu_detect.h>
  27
  28 #if CPU_AVR
  29
  30         #ifdef __AVR_ENHANCED__
  31                 #define pgm_read_char(addr) \
  32                 ({ \
  33                         uint16_t __addr16 = (uint16_t)(addr); \
  34                         uint8_t __result; \
  35                         __asm__ \
  36                         ( \
  37                                 "lpm %0, Z" "\n\t" \
  38                                 : "=r" (__result) \
  39                                 : "z" (__addr16) \
  40                         ); \
  41                         __result; \
  42                 })
  43         #else
  44                 #define pgm_read_char(addr) \
  45                 ({ \
  46                         uint16_t __addr16 = (uint16_t)(addr); \
  47                         uint8_t __result; \
  48                         __asm__ \
  49                         ( \
  50                                 "lpm" "\n\t" \
  51                                 "mov %0, r0" "\n\t" \
  52                                 : "=r" (__result) \
  53                                 : "z" (__addr16) \
  54                                 : "r0" \
  55                         ); \
  56                         __result; \
  57                 })
  58         #endif
  59
  60         #define PROGMEM  __attribute__((__progmem__))
  61         #define PSTR(s) ({static const char __c[] PROGMEM = (s); __c;})
  62
  63 #elif CPU_HARVARD
  64         #error Missing CPU support
  65 #endif
  66
  67 #ifndef PSTR
  68 #define PSTR            /* nothing */
  69 #endif
  70
  71 #ifndef PROGMEM
  72 #define PROGMEM                /* nothing */
  73 #endif
  74
  75 /*!
  76  * \name Types for variables stored in program memory (harvard processors).
  77  * \{
  78  */
  79 typedef PROGMEM char pgm_char;
  80 typedef PROGMEM int8_t pgm_int8_t;
  81 typedef PROGMEM uint8_t pgm_uint8_t;
  82 typedef PROGMEM int16_t pgm_int16_t;
  83 typedef PROGMEM uint16_t pgm_uint16_t;
  84 typedef PROGMEM int32_t pgm_int32_t;
  85 typedef PROGMEM uint32_t pgm_uint32_t;
  86 /*\}*/
  87
  88 /*!
  89  * \def PGM_READ_CHAR
  90  * \def PGM_FUNC
  91  * \def PGM_ATTR
  92  *
  93  * These macros enable dual compilation of code for both program
  94  * and data memory.
  95  *
  96  * Such a function may be defined like this:
  97  *
  98  * \code
  99  *      void PGM_FUNC(lcd_puts)(PGM_ATTR const char *str)
 100  *      {
 101  *              char c;
 102  *              while ((c = PGM_READ_CHAR(str++))
 103  *                      lcd_putchar(c);
 104  *      }
 105  * \endcode
 106  *
 107  * The above code can be compiled twice: once with the _PROGMEM preprocessor
 108  * symbol defined, and once without.  The two object modules can then be
 109  * linked in the same application for use by client code:
 110  *
 111  * \code
 112  *      lcd_puts("Hello, world!");
 113  *      lcd_puts_P(PSTR("Hello, world!"));
 114  *
 115  *      // To be used when invoking inside other PGM_FUNC functions:
 116  *      PGM_FUNC(lcd_puts)(some_string);
 117  * \endcode
 118  */
 119 #ifdef _PROGMEM
 120         #define PGM_READ_CHAR(s) pgm_read_char(s)
 121         #define PGM_FUNC(x)      x ## _P
 122         #define PGM_ATTR         PROGMEM
 123 #else
 124         #define PGM_READ_CHAR(s) (*(s))
 125         #define PGM_FUNC(x)      x
 126         #define PGM_ATTR         /* nothing */
 127 #endif
 128
 129
 130 #endif /* MWARE_PGM_H */