Hi, On Fri, Mar 4, 2011 at 8:18 PM, Paul D. DeRocco <pdero...@ix.netcom.com> wrote: >> From: Quanren Xiong >> >> The hardware is KwikByte KB9200 board from eCosCentric, which >> is based on the ARM9 AT91RM9200 processor. But more RAM and >> ROM are added. >> >> I am new to the ARM architecture. Can someone confirm the >> processor does NOT generate exception on dividing by 0? > > ARM does division in software, so it's up to the library routine. When I > worked with ARM/eCos a few years ago, division by zero didn't invoke any > exception; I doubt that has changed. > >> Another odd thing I found is that It does NOT generate bad >> memory alignment exception either. For example, the following >> code will run just fine: >> >> unsigned int addr=0x00040041; >> *(int *)addr=0xFEFEFEFE; >> >> Should it generate a bad alignment exception? > > Alignment faults can be enabled in register CP15. You should download the > data sheet on the processor from Atmel, and the one on the core itself from > ARM, so you can figure this stuff out. So the registers controlling exception handling are not set up correctly during boot-up on my platform. Given that few pepople complain about it, I would assume it is fixed in Ecos 3.0. Can anybody point me to the code in Ecos 3.0 ARM9 (or maybe AT91RM9200) HAL that does the boot-up initialization? I am stuck with Ecos 2.0 and have to backport the fix to 2.0.
Thanks, Quanren > -- > > Ciao, Paul D. DeRocco > Paul mailto:pdero...@ix.netcom.com > > > -- > Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos > and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss > > -- Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss
