I use paging for virtual memory, which gives each process it's own address space. I have a round-robin scheduler connected to the PIT driver, so every 10ms the PIT fires an interrupt which triggers the scheduler, which selects the next task, saves the current state of the previous task, switches to the new address space, switches the stack, restores registers of the task, then uses the iretq instruction to switch to ring 3 user mode and jump to the instruction pointer.
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I use paging for virtual memory, which gives each process it's own address space. I have a round-robin scheduler connected to the PIT driver, so every 10ms the PIT fires an interrupt which triggers the scheduler, which selects the next task, saves the current state of the previous task, switches to the new address space, switches the stack, restores registers of the task, then uses the iretq instruction to switch to ring 3 user mode and jump to the instruction pointer.