vector table and the linker with M52235EVB

[vale]

Hallo,

I experienced a behaviour of the CodeWarrior linker on my M52235EVB I can't understand.

I wrote down an ISR for my UART1 and I wanted to insert its identifier in the vector table at the proper entry.

Find below my first attempt in file MCF52235_vectors.s:

/*
 * File: vectors.s
 * Purpose: MCF52235 vector table
 */

#ifdef __GNUC__ /* { */
#define sr %sr
#define _ethernet_handler ethernet_handler
#define _irq_handler      irq_handler
#define _timer_handler    timer_handler

#endif /* } __GNUC__ */

 .global VECTOR_TABLE
 .global _VECTOR_TABLE
 .global start

 .extern ___SP_INIT
 .extern _asm_startmeup
 .extern _asm_exception_handler
 .extern _irq_handler
 .extern _ethernet_handler
 .extern _timer_handler
 .extern _ephy_handler
 .extern _irq1_handler
 .extern _irq4_handler
 .extern _irq7_handler
 .extern _irq11_handler
 .extern rd_uart1_isr
 .text

... etc....etc

vector4C: .long _irq_handler
vector4D: .long _irq_handler
/*vector4E: .long _irq_handler*/
vector4E: .long rd_uart1_isr       /* UART1 ISR */
vector4F: .long _irq_handler
vector50: .long _irq_handler

...etc...etc

When I try to compile, I get this message back:

Link Error   : Undefined : "rd_uart1_isr"
Referenced from "start" in mcf52235_vectors.s

Link failed.

I next tried this different solution:

/*
 * File: vectors.s
 * Purpose: MCF52235 vector table
 */

#ifdef __GNUC__ /* { */
#define sr %sr
#define _ethernet_handler ethernet_handler
#define _irq_handler      irq_handler
#define _timer_handler    timer_handler
#define _rd_uart1_isr   rd_uart1_isr

#endif /* } __GNUC__ */

 .global VECTOR_TABLE
 .global _VECTOR_TABLE
 .global start

 .extern ___SP_INIT
 .extern _asm_startmeup
 .extern _asm_exception_handler
 .extern _irq_handler
 .extern _ethernet_handler
 .extern _timer_handler
 .extern _ephy_handler
 .extern _irq1_handler
 .extern _irq4_handler
 .extern _irq7_handler
 .extern _irq11_handler
 .extern _rd_uart1_isr
 .text

...etc...etc

vector48: .long _irq_handler
vector49: .long _irq_handler
vector4A: .long _irq_handler
vector4B: .long _irq_handler
vector4C: .long _irq_handler
vector4D: .long _irq_handler
/*vector4E: .long _irq_handler*/
vector4E: .long _rd_uart1_isr /* UART1 ISR */
vector4F: .long _irq_handler
vector50: .long _irq_handler
vector51: .long _irq_handler

and it worked.

I don't understand this behaviour....the preprocessor should do his work before linking....

what happens different this time with respect to the previous time?

Thank you for any help.

Vale

[CrasyCat]

Hello

I assume rd_uart1_isr is implemented in a C source file. Am I right?

If  this is the case, make sure the function is not static.

Then the compiler add a _ prefix to the function name internally.

So your assembly source file should look like:

.extern _rd_uart1_isr
 .text
 
... etc....etc
 
vector4C: .long _irq_handler
vector4D: .long _irq_handler
/*vector4E: .long _irq_handler*/
vector4E: .long _rd_uart1_isr       /* UART1 ISR */
vector4F: .long _irq_handler
vector50: .long _irq_handler

CrasyCat

[vale]

You were right,

function rd_uart1_isr is implemented in a C source file and it is not static.

Simply adding a '_' to the name of the function in the vector table and in the .extern declaration

made it work, as you told me.

I didn't find any reference on the fact that the compiler adds the '_' internally to the function name.

Could you indicate me where I can find appropriate documentation?

Thank you,

Valentina

[CrasyCat]

Hello

I do not think this is documented anywhere .

Unfortunately.

CrasyCat