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import pytest
import time
from atk16_asm import assemble
from atk16_emu import Machine
from test.utils import pad_bytearray
@pytest.mark.skip(reason="no way of currently fixing this")
def test_emulation_speed():
filename = "test/e2e/emulation_speed/long_loop.atk16"
with open(filename, "r") as f:
source = f.read()
obj = assemble(source, filename)
rom_image = pad_bytearray(obj.program)
machine = Machine()
machine.load_rom_image(rom_image)
machine.reset()
start = time.perf_counter_ns()
machine.run_until_halted()
end = time.perf_counter_ns()
machine.print_state_summary()
elapsed = end - start
print("Elapsed time:", elapsed, "ns")
steps_taken = machine.steps_taken
mean_ns_per_instr = elapsed / steps_taken
print("Instructions / second:", steps_taken / (elapsed / 1e9))
print("ns / instruction:", mean_ns_per_instr)
# VGA frequency is 25.175 MHz
# Divided by 16, that's 1.5734375 MHz (main clock)
# Instructions take 3–5 cycles, the average instruction takes around 4 cycles
# 1.5734375 MHz / 4 = 393359.375 Hz
# That is the goal instruction frequency
# TODO limit emulation speed to 393359.375 Hz ~= 2542 ns per instruction
# this is in order to have similar speed as the actual machine
expected = 2542
allowed_range = 0.05 # 0..1
expected_min = expected * (1 - allowed_range)
expected_max = expected * (1 + allowed_range)
percentage = 100 * mean_ns_per_instr / expected
assert expected_min < mean_ns_per_instr, f"Emulator seems to run too fast ({percentage:.2f}% of expected ns per instruction)"
assert mean_ns_per_instr < expected_max, f"Emulator seems to run too slow ({percentage:.2f}% of expected ns per instruction)"
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