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ARM vectors.S question
- To: ecos <ecos-discuss at sourceware dot cygnus dot com>
- Subject: [ECOS] ARM vectors.S question
- From: Grant Edwards <grante at visi dot com>
- Date: Tue, 26 Oct 1999 15:44:48 -0500
I'm in the process of getting eCOS to run on a Samsung SNDS eval board
(ARM7TDMI core w/ a bunch of on-chip Samsung peripherals). The file
ecos-1.2.1/packages/hal/arm/arch/v1_2_1/src/vectors.S claims to be
platform independent, yet it seems to make assumptions about the
memory map that are platform-dependent.
For example, it assumes that there is RAM at address 0 so the
startup code initializes the exception vectors that are at address 0.
After reset, the SNDS board has ROM at address 0, as will any embedded
system (if I understand the processor startup sequence). There are
two ways to deal with this:
1) The SNDS ROM vectors interrupts via a table of addresses that is
in RAM, so user code can install pointers to ISRs in RAM at a
particular address (0x13fffd0, FWIW).
2) The memory configuration can be altered after startup to re-map RAM
to address 0 and ROM to somewhere else.
Either of these would require changes to "platform independent"
sections of eCOS.
Am I missing something?
--
Grant Edwards
grante@visi.com