.globl switch



.extern kvar_stack_pma

switch:

    # TODO: Check if we come from kernel mode (use kernel stack)
    # TODO: restore all registers

    mov 96(%rdi), %ax
    mov %ax, %ds
    mov %ax, %es
    mov %ax, %fs
    mov %ax, %gs
   
    mov (%rdi), %rax
    mov %rax, %cr3

    push 96(%rdi)
    push 64(%rdi)
    pushf
    pop %rax
    or $0x200, %rax # Enable interrupt
    mov $0xffffffffbfff, %rbx # NT flag
    and %rbx, %rax
    push %rax
    push 40(%rdi)
    push 48(%rdi)


    # Perform task switching
    iretq