[ECOS] Initialization of an ARM - File "vector.S"

[Tristan CORCELLE]

Hi all,

I'm working on a processor based on an ARM7TDMI. To initialize my board, I
have to write the file "hal_board_setup.h".
So, I'm trying to understand the file "vector.S" included in
"hal/arm/arch/src/" but I have problems.

1) What does mean :

#define PTR(name)               \
.##name: .word  name

What is the result when I write PTR(undefined_instruction) ?


2) The exception handlers are put at 0x00000000 but I don't understand what
are the "vectors" next to them (at 0x20). What is the idea?


3) When there is :

        .global __exception_handlers
__exception_handlers:
                ......

 What is the difference between these three lines?

    ldr     r1,__exception_handlers
    ldr     r1,.__exception_handlers
    ldr     r1,=__exception_handlers

(I didn't find anything like that in the ARM web site)


     Thanks in advance
       Regards
           Tristan



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