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#ifndef TABLES_H
#define TABLES_H
/*
* Macros for dealing with linker-generated tables of fixed-size
* symbols. We make fairly extensive use of these in order to avoid
* ifdef spaghetti and/or linker symbol pollution. For example,
* instead of having code such as
*
* #ifdef CONSOLE_SERIAL
* serial_init();
* #endif
*
* we make serial.c generate an entry in the initialisation function
* table, and then have a function call_init_fns() that simply calls
* all functions present in this table. If and only if serial.o gets
* linked in, then its initialisation function will be called. We
* avoid linker symbol pollution (i.e. always dragging in serial.o
* just because of a call to serial_init()) and we also avoid ifdef
* spaghetti (having to conditionalise every reference to functions in
* serial.c).
*
* The linker script takes care of assembling the tables for us. All
* our table sections have names of the format ".tbl.NAME.NN" where
* NAME designates the data structure stored in the table
* (e.g. "init_fn") and NN is a two-digit decimal number used to
* impose an ordering upon the tables if required. NN=00 is reserved
* for the symbol indicating "table start", and NN=99 is reserved for
* the symbol indicating "table end".
*
* To define an entry in the "xxx" table:
*
* static struct xxx my_xxx __table(xxx,01) = { ... };
*
* To access start and end markers for the "xxx" table:
*
* static struct xxx xxx_start[0] __table_start(xxx);
* static struct xxx xxx_end[0] __table_end(xxx);
*
* See init.h and init.c for an example of how these macros are used
* in practice.
*
*/
#define __table_str(x) #x
#define __table_section(table,idx) \
__section__ ( ".tbl." __table_str(table) "." __table_str(idx) )
#define __table_section_start(table) __table_section(table,00)
#define __table_section_end(table) __table_section(table,99)
#define __table(table,idx) __attribute__ (( __table_section(table,idx) ))
#define __table_start(table) __attribute__ (( __table_section_start(table) ))
#define __table_end(table) __attribute__ (( __table_section_end(table) ))
#endif /* TABLES_H */
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