Re: Data to fill into unused program space on ARM7.

In article <hoCdnYM27N58SqLVnZ2dnUVZ_uqdnZ2d@xxxxxxxxxxxx>,
DanishGuy <mij@xxxxxxxxx> wrote:
One problem with most of the solutions is that I'm using ARM and THUMB
instructions. A THUMB jump to the reset vector might mean something else in
ARM. The best solution would be to find some data that is illegal in both
ARM and THUMB. If for instance 0xDEAD is illegal for THUMB, and 0xDEADDEAD
is illegal for ARM, them my problem would be solved.

Does anybody have a suggestion?

Looking at the ARM manual, the pattern 0xEFFF might work. In Thumb mode,
it's an undefined instruction (BLX with the LSB=1). In 32-bit mode, it's
a software interrupt (SWI #0xFFEFFF). Either one ought to land the processor
in an ISR and you can recover from there. I haven't actually tried this. :)

--
Wim Lewis <wiml@xxxxxxxx>, Seattle, WA, USA. PGP keyID 27F772C1
.

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