On Sat, Oct 29, 2005 at 02:27:47AM +1000, Andreas Pfeil wrote: > in the startup code for the ss555 BSP, at the end of the _InitSS555 > function, exception table relocation is activated. > > _CPU_MSR_GET(msr); > msr |= MSR_IP; /* set prefix for exception relocation */ > _CPU_MSR_SET(msr); > > As I understand it, this would make the CPU look for its exception > vector table at 0xFFF00000 to 0xFFF00100. - However, the .vectors > section is linked at address 0x0 to 0x100. In the MPC555, the Burst Buffer Controller can be programmed to remap the exception table into a much smaller space. The CPU thinks it's fetching the first instruction of an interrupt handler from a standard table 0xFFF00000, but the BBC remaps the access to a much smaller table at 0x00000000. See sections 3.11.5 and 4.5 of the MPC555 User's Manual for a description of the mechanism. Regards, David Querbach Real-Time Systems Inc.
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