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Import definitions/macros

Shayan Farsi

Hello...

Currently I am using a header file that contains imported variables/functions/arrays at specific addressing. This is not ideal but it is the only workaround I have for my project. Now I'm trying to modularize my code therefore I am not able to include this header file in all modules as it will cause linker errors. I am using extern to get around that for var declarations. I was wondering if there is any way to import #define 's other than simply copying them over to each module. The following super rough code is to elaborate what I mean.

/* mem_import.h */
#ifndef MEM_IMPORT_H
#define MEM_IMPORT_H

volatile int flags _at_ 0;
#define flags_array ((uint8_t xdata *)(0x0080))
#define operate_flags() (*(void (code *)(void))(0x00ff))()

#endif

/* main.c */
#include "module_a.h"
#include "module_b.h"
#include "mem_import.h"


/* module_a.c */
// #include "mem_import.h"
extern volatile int flags;

/* module_b.c */
//#include "mem_import.h"
extern volatile int flags;

I would like to be able to use the 'operate_flags()' and 'flag_array' macros in each module. Is there any way to do this that doesn't involve including the mem_imports.h or simply copying it over where ever it's needed. The reason I don't want to copy it over is I will loose the modularization because of the specific addressing.

Thanks for any help in advance and let me know if more clarification is needed.

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  • 0 in reply to Shayan Farsi

    Take a closer look at the instruction set of the processor, and you would see that the processor does not have any great _general_ instructions for indurect addressing.

    That also affects the ability to use a _real_ stack with indirect addressing of parameters and local variables relative to a base pointer. Which makes the C51 compiler convert parameters and local variables into reused global variables. And that optimization requirs the compiler/linker to know exactly what functions that can call other functions - how else would the compiler/linker know which two different local variables that can share the same global memory address?

    The 8051 architecture is extremely hostile for use with high-level languages.

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  • 0 in reply to Shayan Farsi

    Take a closer look at the instruction set of the processor, and you would see that the processor does not have any great _general_ instructions for indurect addressing.

    That also affects the ability to use a _real_ stack with indirect addressing of parameters and local variables relative to a base pointer. Which makes the C51 compiler convert parameters and local variables into reused global variables. And that optimization requirs the compiler/linker to know exactly what functions that can call other functions - how else would the compiler/linker know which two different local variables that can share the same global memory address?

    The 8051 architecture is extremely hostile for use with high-level languages.

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