1 files changed, 43 insertions, 0 deletions
diff --git a/test/e2e/emulation_speed/test_emulation_speed.py b/test/e2e/emulation_speed/test_emulation_speed.py
new file mode 100644
index 0000000..f2bcd22
--- /dev/null
+++ b/test/e2e/emulation_speed/test_emulation_speed.py
@@ -0,0 +1,43 @@
+import time
+from atk16_asm import assemble
+from atk16_emu import Machine
+from test.utils import pad_bytearray
+
+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)"