Macros for program memory access.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@368 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/mware/pgm.h b/mware/pgm.h
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+/*!
+ * \file
+ * <!--
+ * Copyright 2004, 2005 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2004 Giovanni Bajo
+ * This file is part of DevLib - See README.devlib for information.
+ * -->
+ *
+ * \brief Support for reading program memory on Harvard architectures.
+ *
+ * Support is currently provided for AVR microcontrollers only.
+ *
+ * These macros allow building code twice, with and without
+ * pgm support (e.g.: strcpy() and strcpy_P()).
+ *
+ * Set the _PROGMEM predefine to compile in conditional
+ * program-memory support.
+ *
+ *
+ * \note This module contains code ripped out from avr-libc,
+ *       which is distributed under a 3-clause BSD license.
+ */
+#ifndef MWARE_PGM_H
+#define MWARE_PGM_H
+
+#include <cpu_detect.h>
+
+#if CPU_AVR
+
+       #ifdef __AVR_ENHANCED__
+               #define pgm_read_char(addr) \
+               ({ \
+                       uint16_t __addr16 = (uint16_t)(addr); \
+                       uint8_t __result; \
+                       __asm__ \
+                       ( \
+                               "lpm %0, Z" "\n\t" \
+                               : "=r" (__result) \
+                               : "z" (__addr16) \
+                       ); \
+                       __result; \
+               })
+       #else
+               #define pgm_read_char(addr) \
+               ({ \
+                       uint16_t __addr16 = (uint16_t)(addr); \
+                       uint8_t __result; \
+                       __asm__ \
+                       ( \
+                               "lpm" "\n\t" \
+                               "mov %0, r0" "\n\t" \
+                               : "=r" (__result) \
+                               : "z" (__addr16) \
+                               : "r0" \
+                       ); \
+                       __result; \
+               })
+       #endif
+
+       #define PROGMEM  __attribute__((__progmem__))
+       #define PSTR(s) ({static const char __c[] PROGMEM = (s); __c;})
+
+#elif CPU_HARVARD
+       #error Missing CPU support
+#endif
+
+#ifndef PSTR
+#define PSTR            /* nothing */
+#endif
+
+#ifndef PROGMEM
+#define PROGMEM                /* nothing */
+#endif
+
+/*!
+ * \name Types for variables stored in program memory (harvard processors).
+ * \{
+ */
+typedef PROGMEM char pgm_char;
+typedef PROGMEM int8_t pgm_int8_t;
+typedef PROGMEM uint8_t pgm_uint8_t;
+typedef PROGMEM int16_t pgm_int16_t;
+typedef PROGMEM uint16_t pgm_uint16_t;
+typedef PROGMEM int32_t pgm_int32_t;
+typedef PROGMEM uint32_t pgm_uint32_t;
+/*\}*/
+
+/*!
+ * \def PGM_READ_CHAR
+ * \def PGM_FUNC
+ * \def PGM_ATTR
+ *
+ * These macros enable dual compilation of code for both program
+ * and data memory.
+ *
+ * Such a function may be defined like this:
+ *
+ * \code
+ *     void PGM_FUNC(lcd_puts)(PGM_ATTR const char *str)
+ *     {
+ *             char c;
+ *             while ((c = PGM_READ_CHAR(str++))
+ *                     lcd_putchar(c);
+ *     }
+ * \endcode
+ *
+ * The above code can be compiled twice: once with the _PROGMEM preprocessor
+ * symbol defined, and once without.  The two object modules can then be
+ * linked in the same application for use by client code:
+ *
+ * \code
+ *     lcd_puts("Hello, world!");
+ *     lcd_puts_P(PSTR("Hello, world!"));
+ *
+ *     // To be used when invoking inside other PGM_FUNC functions:
+ *     PGM_FUNC(lcd_puts)(some_string);
+ * \endcode
+ */
+#ifdef _PROGMEM
+       #define PGM_READ_CHAR(s) pgm_read_char(s)
+       #define PGM_FUNC(x)      x ## _P
+       #define PGM_ATTR         PROGMEM
+#else
+       #define PGM_READ_CHAR(s) (*(s))
+       #define PGM_FUNC(x)      x
+       #define PGM_ATTR         /* nothing */
+#endif
+
+
+#endif /* MWARE_PGM_H */