1 files changed, 81 insertions, 5 deletions
diff --git a/atk16_emu/test/test_opcode_alr.py b/atk16_emu/test/test_opcode_alr.py
index 8561ff6..e7fe1a7 100644
--- a/atk16_emu/test/test_opcode_alr.py
+++ b/atk16_emu/test/test_opcode_alr.py
@@ -1,7 +1,7 @@
 from ..emu import Machine
 from .utils import make_rom
 
-def test_alr_s0_small_unsigned():
+def test_alr_add_small_unsigned():
   machine = Machine()
 
   rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
@@ -20,7 +20,7 @@ def test_alr_s0_small_unsigned():
   assert machine.fr.zero == 0
   assert machine.fr.sign == 0
 
-def test_alr_s0_large_unsigned():
+def test_alr_add_large_unsigned():
   machine = Machine()
 
   rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
@@ -39,7 +39,7 @@ def test_alr_s0_large_unsigned():
   assert machine.fr.zero == 0
   assert machine.fr.sign == 0
 
-def test_alr_s0_small_signed():
+def test_alr_add_small_signed():
   machine = Machine()
 
   rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
@@ -58,7 +58,7 @@ def test_alr_s0_small_signed():
   assert machine.fr.zero == 1
   assert machine.fr.sign == 0
 
-def test_alr_s0_large_signed():
+def test_alr_add_large_signed():
   machine = Machine()
 
   rom_image = make_rom([0b0000_010_000_001_000]) # ALR target=RC left=RA right=RB alu_code=0
@@ -75,4 +75,80 @@ def test_alr_s0_large_signed():
   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
+  assert machine.fr.sign == 1
+
+def test_alr_sub_small_unsigned():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_001]) # ALR target=RC left=RA right=RB alu_code=1
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 10
+  machine.rb.value = 20
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0xFFF6 # -10
+  assert machine.fr.carry == 1
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 1
+
+def test_alr_sub_large_unsigned():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_001]) # ALR target=RC left=RA right=RB alu_code=1
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0xFFFF
+  machine.rb.value = 0xFFFF
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0x0000
+  assert machine.fr.carry == 0
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 1
+  assert machine.fr.sign == 0
+
+def test_alr_sub_small_signed():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_001]) # ALR target=RC left=RA right=RB alu_code=1
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0x0001 # 1
+  machine.rb.value = 0xFFFF # -1
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0x0002
+  assert machine.fr.carry == 1
+  assert machine.fr.overflow == 0
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 0
+
+def test_alr_sub_large_signed():
+  machine = Machine()
+
+  rom_image = make_rom([0b0000_010_000_001_001]) # ALR target=RC left=RA right=RB alu_code=1
+  machine.load_rom_image(rom_image)
+  machine.reset()
+
+  machine.ra.value = 0x7FFF # 32767
+  machine.rb.value = 0xFFFF # -1
+
+  machine.run()
+  machine.step()
+
+  assert machine.rc.value == 0x8000 # -32768
+  assert machine.fr.carry == 1
+  assert machine.fr.overflow == 1
+  assert machine.fr.zero == 0
+  assert machine.fr.sign == 1