On 9/26/07, Andy Fleming afleming@gmail.com wrote:
On 9/26/07, robert lazarski robertlazarski@gmail.com wrote:
Hi all,
Starting with the basics: R1 has a 4K stack from 0xfffff000-0xffffffff and the stack grows down?
It better not. r1 will eventually have a stack somewhere. Initially, we put it in unmapped memory space which allows us to use the cache as memory. 0xfffff000-0xffffffff is the last page in memory, and that is a) in Flash, and b) the boot page. Until you execute the code you're having a problem with below, that last page will be the only page mapped.
Can I get clarification on one point in particular here please? Before the TLB's get processed, IVPR is set to the TEXT_BASE - 0xfff80000 - and then IVOR15 is set to 0x0f00, ie 'Debug' interrupt type is mapped to 0xfff80f00 . If that is correct, isn't 0xfff80f00 unmapped, since only the last page 0xfffff000-0xffffffff is mapped?
I ask because for bdi, debugging works only if the Debug Interrupt (IVOR15) points to a valid, mapped and therefore executable opcode. If not then the core crashes. I ask because I may have a TLB issue and I'm having a hard finding it. Or maybe the bdi core is crashing simply because IVOR15 is not an executable opcode ?
Thanks all, I hope I'm asking valid questions that are of general interest, Robert