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Hi I am using spim simulator pcspim and I am trying to set a value at an address using the set value option under the simulator menu.

When I try to set a value which has an msb of 1 for ex. oxb1234567 the value at that address is defaulted to 7fffffff, can anyone explain the reason for this behaviour.

Any help appreciated

koool
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In MIPS, addresses starting with 1 (MSB = 1) indicate kernel memory space. You cannot access kernel space from user space (which has MSB = 0) without using syscalls.

m0skit0
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  • i think u got me wrong .... the msb of my address is not 1 ...... the msb of my value is 1 – koool Sep 29 '11 at 10:23
  • Oh sorry, I read it wrong. Well I don't know why that happens. I might recommend [MARS](http://courses.missouristate.edu/KenVollmar/MARS/) as a better MIPS simulator IMHO. – m0skit0 Sep 29 '11 at 10:30