Add emu

4 files changed, 121 insertions, 0 deletions

diff --git a/atk16_emu/test/__init__.py b/atk16_emu/test/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/atk16_emu/test/__init__.py
diff --git a/atk16_emu/test/test_opcode_alr.py b/atk16_emu/test/test_opcode_alr.py
new file mode 100644
index 0000000..c54d70e
--- /dev/null
+++ b/atk16_emu/test/test_opcode_alr.py
@@ -0,0 +1,78 @@
+from atk16_emu.emu import Machine
+from atk16_emu.test.utils import make_rom
+
+def test_alr_s0_small_unsigned():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 10
+  machine.rb.value = 20
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 30
+  assert machine.fr.carry == 0
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 0
+
+def test_alr_s0_large_unsigned():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0xFFFF
+  machine.rb.value = 20
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 19
+  assert machine.fr.carry == 1
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 0
+
+def test_alr_s0_small_signed():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0xFFFF # -1
+  machine.rb.value = 0x0001 # 1
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0
+  assert machine.fr.carry == 1
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 1
+  assert machine.fr.sign == 0
+
+def test_alr_s0_large_signed():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0x7FFF # 32767
+  machine.rb.value = 0x0001 # 1
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0x8000 # -32768
+  assert machine.fr.carry == 0
+  assert machine.fr.overflow == 1
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 1
\ No newline at end of file
diff --git a/atk16_emu/test/test_opcode_hlt.py b/atk16_emu/test/test_opcode_hlt.py
new file mode 100644
index 0000000..5cae888
--- /dev/null
+++ b/atk16_emu/test/test_opcode_hlt.py
@@ -0,0 +1,18 @@
+from atk16_emu.emu import Machine
+from atk16_emu.test.utils import make_rom
+
+def test_hlt():
+  machine = Machine()
+
+  rom_image = make_rom([0b1111_0000_0000_0000]) # HLT
+  machine.load_rom_image(rom_image)
+  machine.reset()
+  machine.run()
+
+  assert machine.pc.value == 0
+  assert machine.running == True
+
+  machine.step()
+
+  assert machine.pc.value == 1
+  assert machine.running == False
diff --git a/atk16_emu/test/utils.py b/atk16_emu/test/utils.py
new file mode 100644
index 0000000..0d40d54
--- /dev/null
+++ b/atk16_emu/test/utils.py
@@ -0,0 +1,25 @@
+def pad_bytearray(to_length: int, ba: bytearray) -> bytearray:
+  """
+  Pads a bytearray with zeros until it reaches a specified length.
+
+  :param to_length: Target length in bytes.
+  :param ba: The bytearray to be padded.
+  :return: The padded bytearray.
+  """
+  padding_size = to_length - len(ba)
+  if padding_size > 0:
+    ba.extend(b'\x00' * padding_size)
+  return ba
+
+def make_rom(words: list[int]) -> bytearray:
+  """
+  Constructs a ROM image from a list of 16-bit words.
+
+  :param words: The list of 16-bit words.
+  :return: The ROM image as a bytearray.
+  """
+  bytes = []
+  for word in words:
+    bytes.append((word >> 8) & 0xFF)
+    bytes.append(word & 0xFF)
+  return pad_bytearray(64 * 1024, bytearray(bytes))
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