Stage 3

XSM Machine Organisation XSM Instruction Set Virtual Machine Model

When the XSM Machine is started up, the ROM Code that resides at page 0 is executed. It is hard-coded into the machine. The ROM code is called "Boot ROM".

1) Loads block 0 of the disk to page 1 of the memory 2) After loading the block to memory, it sets the value of register IP to 512 so that next instruction is fetched from location 512.

Load the OS Startup code to Block 0 and use XSM Simulator to run the machine

What happens when Interrupt is called

1) IP+2 pushed into the User Stack 2) Searches the IVT and IP is set to the handler's first instruction