for my code
import pyrtl

main_memory = pyrtl.MemBlock(bitwidth=32, addrwidth=32, name="main_mem", asynchronous= True)

virtual_addr_i        = pyrtl.Input(bitwidth=32, name="virtual_addr_i")
new_req_i             = pyrtl.Input(bitwidth=1,  name="new_req_i")
reset_i               = pyrtl.Input(bitwidth=1,  name="reset_i")
req_type_i            = pyrtl.Input(bitwidth=1,  name="req_type_i")

physical_addr_o       = pyrtl.Output(bitwidth=32,name="physical_addr_o")
dirty_o               = pyrtl.Output(bitwidth=1, name="dirty_o")
valid_o               = pyrtl.Output(bitwidth=1, name="valid_o")
ref_o                 = pyrtl.Output(bitwidth=1, name="ref_o")
error_code_o          = pyrtl.Output(bitwidth=3, name="error_code_o")
finished_walk_o       = pyrtl.Output(bitwidth=1, name="finished_walk_o")

page_fault          = pyrtl.WireVector(bitwidth=1, name="page_fault")
state               = pyrtl.Register(bitwidth=2, name="state")
base_register       = pyrtl.Const(0x3FFBFF, bitwidth=22)

# Step 1 : Split input into the three offsets
writable_o = pyrtl.WireVector(bitwidth=1, name="writable_o")
readable_o = pyrtl.WireVector(bitwidth=1, name="readable_o")
saved_entry1 = pyrtl.Register(bitwidth=32, name="saved_entry1")
saved_entry2 = pyrtl.Register(bitwidth=32, name="saved_entry2")
mem_read_addr = pyrtl.WireVector(bitwidth=32, name = "read_addr")

offset3 = virtual_addr_i[0:12] # physical address
offset2 = virtual_addr_i[12:22] # second walk
offset1 = virtual_addr_i[22:32] # first walk

levelOneAddress = pyrtl.concat(base_register, offset1)
levelTwoBase = saved_entry1[0:22]
levelTwoAddress = pyrtl.concat(levelTwoBase, offset2)

with pyrtl.conditional_assignment:
    with state == 1:
        mem_read_addr |= levelOneAddress
    with state == 2:
        mem_read_addr |= levelTwoAddress
    with pyrtl.otherwise:
        mem_read_addr |= 0

current_entry = main_memory[mem_read_addr]

# Step 2 : UPDATE STATE according to state diagram in instructions
with pyrtl.conditional_assignment:
    with state == 1:
        page_fault |= ~current_entry[31]
    with state == 2:
        page_fault |= ~current_entry[31]

with pyrtl.conditional_assignment:
    with state == 0:
        with new_req_i:
            state.next |= 1
        with reset_i:
            state.next |= 0
    with state == 1:
        with page_fault:
            state.next |= 0
        with ~page_fault:
            saved_entry1.next |= current_entry
            state.next |= 2
        with reset_i:
            state.next |= 0
    with state == 2:
        with page_fault:
            state.next |= 0
        with ~page_fault:
            saved_entry2.next |= current_entry
            state.next |= 0
        with reset_i:
            state.next |= 0

# Step 3 : Determine physical address by walking the page table structure
physicalBase = current_entry[0:20]
physicalAddress = pyrtl.concat(physicalBase, offset3)

# Step 4 : Determine the outputs based on the last level of the page table walk
with pyrtl.conditional_assignment:
    with state == 0:
        physical_addr_o |= 0
        dirty_o |= current_entry[30]
        valid_o |= current_entry[31]
        ref_o |= current_entry[29]
        error_code_o |= 0
        finished_walk_o |= 0
    with state == 1:
        with page_fault:
            finished_walk_o |= 1
            error_code_o |= pyrtl.Const(0b001)
        with ~page_fault:
            physical_addr_o |= 0
            dirty_o |= current_entry[30]
            valid_o |= current_entry[31]
            ref_o |= current_entry[29]
            error_code_o |= 0
            finished_walk_o |= 0
    with state == 2:
        dirty_o |= current_entry[30]
        valid_o |= current_entry[31]
        ref_o |= current_entry[29]
        physical_addr_o |= pyrtl.concat(current_entry[0:20], offset3)
        writable_o |= current_entry[28]
        readable_o |= current_entry[27]
        with page_fault:
            finished_walk_o |= 1
            error_code_o |= pyrtl.Const(0b001)
        with ~page_fault:
            with req_type_i == 0:
                with ~readable_o:
                    finished_walk_o |= 1
                    error_code_o |= pyrtl.Const(0b100)
                with pyrtl.otherwise:
                    finished_walk_o |= 1
                    error_code_o |= 0
            with req_type_i == 1:
                with ~writable_o:
                    finished_walk_o |= 1
                    error_code_o |= pyrtl.Const(0b010)
                with pyrtl.otherwise:
                    finished_walk_o |= 1
                    error_code_o |= 0 
write me a testcase to test page faults in state1 and state 2 in the below format
if __name__ == "__main__":

    """
    These memory addresses correspond to the test that we walk through in the instructions
    This just does a basic walk from the first level to the last level where no errors should occur
    """
    memory = {
        4293918528: 0xC43FFC6B,
        4294029192: 0xAC061D26,
        1641180595: 0xDEADBEEF
    }

    sim_trace = pyrtl.SimulationTrace()
    sim = pyrtl.Simulation(tracer=sim_trace, memory_value_map={main_memory: memory})

    for i in range(3):
        sim.step({
            new_req_i: 1,
            reset_i: 0,
            virtual_addr_i: 0xD0388DB3,
            req_type_i: 0
    })

    sim_trace.render_trace(symbol_len=20)

    assert (sim_trace.trace["physical_addr_o"][-1] == 0x61d26db3)
    assert (sim_trace.trace["error_code_o"][-1] == 0x0)
    assert (sim_trace.trace["dirty_o"][-1] == 0x0)
    assert (sim_trace.trace["readable_o"][-1] == 0x1)