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Initialization of an ARM - File "vector.S"
- From: "Tristan CORCELLE" <tco at teamlog dot com>
- To: <ecos-discuss at sources dot redhat dot com>
- Date: Mon, 27 May 2002 14:34:09 +0200
- Subject: [ECOS] Initialization of an ARM - File "vector.S"
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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