[ECOS] ARM vectors.S question

Grant Edwards grante@visi.com
Tue Oct 26 13:44:00 GMT 1999

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

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