EMualtor im

tests/test_emulator_fast_paths.py

@@ -0,0 +1,87 @@
+import unittest
+
+from h8536.emulator.fast_paths import (
+    LOC_C08B_P9_WRITE_BYTE,
+    LOC_C0DB_P9_READ_BYTE,
+    P9FastPath,
+    P9FastPathConfig,
+)
+from h8536.emulator.runner import H8536Emulator
+
+
+def rom_with_reset(*, reset: int = 0x1000, size: int = 0xD000) -> bytearray:
+    rom = bytearray([0xFF] * size)
+    rom[0:2] = reset.to_bytes(2, "big")
+    return rom
+
+
+class P9FastPathTest(unittest.TestCase):
+    def test_disabled_fast_path_does_not_handle_known_pc(self):
+        emulator = H8536Emulator(bytes(rom_with_reset()))
+        emulator.cpu.pc = LOC_C08B_P9_WRITE_BYTE
+
+        fast_path = P9FastPath()
+
+        self.assertFalse(fast_path.try_handle(emulator))
+        self.assertEqual(emulator.cpu.pc, LOC_C08B_P9_WRITE_BYTE)
+
+    def test_c08b_write_byte_logs_r0_sets_success_and_returns_to_caller(self):
+        emulator = H8536Emulator(bytes(rom_with_reset()))
+        emulator.cpu.pc = LOC_C08B_P9_WRITE_BYTE
+        emulator.cpu.regs[0] = 0x12A5
+        emulator.cpu.regs[7] = 0xFE7E
+        emulator.cpu.c = True
+        emulator.cpu.v = True
+        emulator.memory.write16(0xFE7E, 0x3456)
+
+        fast_path = P9FastPath(P9FastPathConfig(enabled=True))
+
+        self.assertTrue(fast_path.try_handle(emulator))
+        self.assertEqual(fast_path.output_bytes, [0xA5])
+        self.assertEqual(fast_path.events[-1].kind, "write_byte")
+        self.assertEqual(fast_path.events[-1].value, 0xA5)
+        self.assertEqual(emulator.cpu.regs[0], 1)
+        self.assertEqual(emulator.cpu.pc, 0x3456)
+        self.assertEqual(emulator.cpu.regs[7], 0xFE80)
+        self.assertFalse(emulator.cpu.z)
+        self.assertFalse(emulator.cpu.n)
+        self.assertFalse(emulator.cpu.v)
+        self.assertTrue(emulator.cpu.c)
+        self.assertEqual(emulator.cpu.steps, 1)
+
+    def test_c0db_read_byte_puts_queued_byte_in_r5_low_and_returns(self):
+        emulator = H8536Emulator(bytes(rom_with_reset()))
+        emulator.cpu.pc = LOC_C0DB_P9_READ_BYTE
+        emulator.cpu.regs[5] = 0xBE00
+        emulator.cpu.regs[7] = 0xFE7C
+        emulator.memory.write16(0xFE7C, 0x4567)
+
+        fast_path = P9FastPath(P9FastPathConfig(enabled=True), input_bytes=[0x3C])
+
+        self.assertTrue(fast_path.try_handle(emulator))
+        self.assertEqual(emulator.cpu.regs[5], 0xBE3C)
+        self.assertEqual(emulator.cpu.pc, 0x4567)
+        self.assertEqual(emulator.cpu.regs[7], 0xFE7E)
+        self.assertEqual(fast_path.events[-1].kind, "read_byte")
+        self.assertEqual(fast_path.events[-1].value, 0x3C)
+        self.assertFalse(emulator.cpu.z)
+        self.assertFalse(emulator.cpu.n)
+        self.assertFalse(emulator.cpu.v)
+
+    def test_c0db_read_byte_uses_default_when_queue_is_empty(self):
+        emulator = H8536Emulator(bytes(rom_with_reset()))
+        emulator.cpu.pc = LOC_C0DB_P9_READ_BYTE
+        emulator.cpu.regs[7] = 0xFE80
+        emulator.memory.write16(0xFE80, 0x5678)
+
+        fast_path = P9FastPath(P9FastPathConfig(enabled=True, default_input_byte=0x81))
+
+        self.assertTrue(fast_path.try_handle(emulator))
+        self.assertEqual(emulator.cpu.regs[5], 0x0081)
+        self.assertEqual(emulator.cpu.pc, 0x5678)
+        self.assertFalse(emulator.cpu.z)
+        self.assertTrue(emulator.cpu.n)
+
+
+if __name__ == "__main__":
+    unittest.main()