diff --git a/asm/ffi.py b/asm/ffi.py
index cb30ce9..39d9800 100644
--- a/asm/ffi.py
+++ b/asm/ffi.py
@@ -45,7 +45,7 @@ class CEnv(Structure):
 		("prglen", c_size_t)
 	]
 
-class ExecutionEnvironment:
+class Environment:
 	def __init__(self, reglen=32, lablen=32, stklen=4096, prglen=4096):
 		cenv = CEnv()
 		cenv.reglen = reglen
diff --git a/asm/test.py b/asm/test.py
index 640f3bf..ba6d125 100644
--- a/asm/test.py
+++ b/asm/test.py
@@ -58,7 +58,7 @@ class PushTest(unittest.TestCase):
 		p.parse_asm_line("PUSH 6")
 		b = p()
 
-		ex = ffi.ExecutionEnvironment()
+		ex = ffi.Environment()
 		self.assertEqual(ex.load(b), ffi.CompileRet.OK)
 		self.assertEqual(ex.cenv.prgend, 2)
 
@@ -78,6 +78,60 @@ class PushTest(unittest.TestCase):
 		self.assertEqual(ex.cenv.prg[1].w[1], 0)
 		self.assertEqual(ex.cenv.prg[1].w[2], 0)
 
+class PopTest(unittest.TestCase):
+	def test_compile_pop_reg(self):
+		p = Program()
+		p.parse_asm_line("pop r9")
+		b = p()
+		self.assertEqual(b, b'\x02\xC2\x89\x00')
+		ex = ffi.Environment()
+		self.assertEqual(ex.load(b), ffi.CompileRet.OK)
+		self.assertEqual(ex.cenv.prgend, 1)
+
+		self.assertEqual(ex.cenv.prg[0].opcode, 2)
+		self.assertEqual(ex.cenv.prg[0].w_flags[0], 1)
+		self.assertEqual(ex.cenv.prg[0].w_flags[1], 0)
+		self.assertEqual(ex.cenv.prg[0].w_flags[2], 0)
+		self.assertEqual(ex.cenv.prg[0].w[0], 9)
+		self.assertEqual(ex.cenv.prg[0].w[1], 0)
+		self.assertEqual(ex.cenv.prg[0].w[2], 0)
+
+	def test_compile_throw_pop_literal(self):
+		p = Program()
+		ex = ffi.Environment()
+		with self.assertRaises(TypecheckException) as cm:
+			p.parse_asm_line("pop 6")
+		self.assertEqual(cm.exception.argtype, ArgType.REG)
+		self.assertEqual(cm.exception.sarg, '6')
+		self.assertEqual(cm.exception.i, 0)
+		self.assertEqual(cm.exception.opcode, 2)
+
+	def test_compile_throw_pop_label(self):
+		p = Program()
+		ex = ffi.Environment()
+		with self.assertRaises(TypecheckException) as cm:
+			p.parse_asm_line("pop l9")
+		self.assertEqual(cm.exception.argtype, ArgType.REG)
+		self.assertEqual(cm.exception.sarg, 'l9')
+		self.assertEqual(cm.exception.i, 0)
+		self.assertEqual(cm.exception.opcode, 2)
+
+	def test_compile_throw_argument_overflow(self):
+		p = Program()
+		with self.assertRaises(TypecheckLenException) as cm:
+			p.parse_asm_line("push r1 r2")
+		self.assertEqual(cm.exception.opcode, 1)
+		self.assertEqual(cm.exception.insargs, ["r1", "r2"])
+		self.assertEqual(cm.exception.argtypelen, 1)
+
+	def test_catch_typecheck_argument_underflow(self):
+		p = Program()
+		with self.assertRaises(TypecheckLenException) as cm:
+			p.parse_asm_line("push")
+		self.assertEqual(cm.exception.opcode, 2)
+		self.assertEqual(cm.exception.insargs, [])
+		self.assertEqual(cm.exception.argtypelen, 1)
+
 class ProgramTest(unittest.TestCase):
 	def test_two(self):
 		p = Program()