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problem in absolute variable location

ERIC WHITESELL

I would appreciate your help to fix this problem:
--------------------------------------------------
<main.c>

// include files
#include "main.h"

// main
int
main(void)
{ //test code for problem in h file

while (reg1) { // wait }
}

// end

<main.h>

volatile unsigned char reg1 __at 0x40004000; //see the semicolon?

// end

<build>

Build target 'Target 1'

compiling main.c...

main.h(1): error: #65: expected a ";"

Target not created

-----------------------------------
Eric

  • 0

    It's always worth doing a search first...

    This very question was answered only the day before yesterday:

    http://www.keil.com/forum/docs/thread9897.asp

    and then was already on the forum:

    http://www.keil.com/forum/docs/thread8677.asp

  • 0 in reply to Andy Neil

    I copied the absacc.h file from ARM/RV30/INC into my project folder and tried this:

    Realview Compiler
    -------------------
    main.c
    -------------------
    #include "absacc.h"
    #include "main.h"

    int
    main(void)
    { int portA; //test code for problem in h file portA = gpio_pins;
    } --------------------
    absacc.h
    --------------------
    /* absacc.h: header file that allows absolute variable location at C level */
    /* Copyright 2006 ARM Limited. All rights reserved. */
    /* version 0.01 */

    #ifndef __at
    #define __at(_addr) __attribute__ \
    ((section (".ARM.__AT_" #_addr)))

    #endif
    ---------------------
    main.h
    ---------------------
    volatile unsigned long gpio_pins __at(0x40004000);
    ---------------------
    Build target 'Target 1'

    compiling main.c...

    main.c(7): warning: #550-D: variable "portA" was set but never used

    linking...

    debug.axf: error: L6938E: Invalid value for --ro-base.

    Target not created

  • 0 in reply to ERIC WHITESELL

    After looking over many posts on this subject, (most of which did not work or were way too messy), this finally took care of the problem:

    #include <absacc.h>
    or copy it from ARM/RV30/INC or from here into your project folder and use
    #include "absacc.h"

    Realview Compiler

    Project
    Options for target (target)
    Linker folder tab
    upper right hand corner
    R/O Base: 0x40000000 (lowest read-only addr)
    R/W Base: 0x40004000 (lowest R/W addr)

    -------------------
    main.c
    -------------------
    #include "absacc.h"
    #include "main.h"

    int
    main(void)
    {

    int test;

    /* test code */

    test = gpio_pins;

    gpio_pins = test;

    }

    --------------------
    absacc.h
    --------------------
    /* absacc.h: header file that allows absolute variable location at C level */
    /* Copyright 2006 ARM Limited. All rights reserved. */
    /* version 0.01 */

    #ifndef __at
    #define __at(_addr) __attribute__ \
    ((section (".ARM.__AT_" #_addr)))

    #endif
    ---------------------
    main.h
    ---------------------
    /* assign variable to absolute location */
    /* use __at with 2 underscores in front and left paren in back */

    volatile unsigned long gpio_pins __at(0x40004000);
    ---------------------
    Build!
    ---------------------
    Build target 'Target 1'
    compiling main.c...
    linking...
    "debug.axf" - 0 Error(s), 0 Warning(s).