diff --git a/.flake8 b/.flake8
index b7c933b..565d47b 100644
--- a/.flake8
+++ b/.flake8
@@ -13,6 +13,7 @@ exclude =
     build,
     dist,
     .conda,
+    .venv,
     tests/autogenerated_*
 
 # Enable specific plugins or options
diff --git a/src/copapy/__init__.py b/src/copapy/__init__.py
index 1e283ba..492442b 100644
--- a/src/copapy/__init__.py
+++ b/src/copapy/__init__.py
@@ -3,22 +3,25 @@ from typing import Generator, Iterable, Any
 from . import binwrite as binw
 from .stencil_db import stencil_database
 
-Operand =  type['Net'] | float | int
+Operand = type['Net'] | float | int
+
 
 def get_var_name(var: Any, scope: dict[str, Any] = globals()) -> list[str]:
     return [name for name, value in scope.items() if value is var]
 
 # _ccode = pkgutil.get_data(__name__, 'stencils.c')
 # assert _ccode is not None
+
+
 sdb = stencil_database('src/copapy/obj/stencils_x86_64_O3.o')
 
 
 class Node:
-    def __init__(self):
+    def __init__(self) -> None:
         self.args: list[Net] = []
         self.name: str = ''
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         #return f"Node:{self.name}({', '.join(str(a) for a in self.args) if self.args else self.value})"
         return f"Node:{self.name}({', '.join(str(a) for a in self.args) if self.args else (self.value if isinstance(self, Const) else '')})"
 
@@ -37,26 +40,26 @@ class Net:
 
     def __rmul__(self, other: Any) -> 'Net':
         return _add_op('mul', [self, other], True)
-    
+
     def __add__(self, other: Any) -> 'Net':
         return _add_op('add', [self, other], True)
 
     def __radd__(self, other: Any) -> 'Net':
         return _add_op('add', [self, other], True)
 
-    def __sub__ (self, other: Any) -> 'Net':
+    def __sub__(self, other: Any) -> 'Net':
         return _add_op('sub', [self, other])
 
-    def __rsub__ (self, other: Any) -> 'Net':
+    def __rsub__(self, other: Any) -> 'Net':
         return _add_op('sub', [other, self])
 
-    def __truediv__ (self, other: Any) -> 'Net':
+    def __truediv__(self, other: Any) -> 'Net':
         return _add_op('div', [self, other])
 
-    def __rtruediv__ (self, other: Any) -> 'Net':
+    def __rtruediv__(self, other: Any) -> 'Net':
         return _add_op('div', [other, self])
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         names = get_var_name(self)
         return f"{'name:' + names[0] if names else 'id:' + str(id(self))[-5:]}"
 
@@ -94,7 +97,7 @@ def _add_op(op: str, args: list[Any], commutative: bool = False) -> Net:
     if commutative:
         arg_nets = sorted(arg_nets, key=lambda a: a.dtype)
 
-    typed_op =  '_'.join([op] + [a.dtype for a in arg_nets])
+    typed_op = '_'.join([op] + [a.dtype for a in arg_nets])
 
     if typed_op not in sdb.function_definitions:
         raise ValueError(f"Unsupported operand type(s) for {op}: {' and '.join([a.dtype for a in arg_nets])}")
@@ -141,24 +144,6 @@ def const_vector3d(x: float, y: float, z: float) -> vec3d:
     return vec3d((const(x), const(y), const(z)))
 
 
-def get_multiuse_nets(root: list[Node]) -> set[Net]:
-    """Finds all nets that get accessed more than one time. Therefore
-    storage on the heap might be better.
-    """
-    known_nets: set[Net] = set()
-
-    def recursive_node_search(net_list: Iterable[Net]) -> Generator[Net, None, None]:
-        for net in net_list:
-            #print(net)
-            if net in known_nets:
-                yield net
-            else:
-                known_nets.add(net)
-                yield from recursive_node_search(net.source.args)
-
-    return set(recursive_node_search(op.args[0] for op in root))
-
-
 def get_path_segments(root: Iterable[Node]) -> Generator[list[Node], None, None]:
     """List of all possible paths. Ops in order of execution (output at the end)
     """
@@ -190,7 +175,7 @@ def get_ordered_ops(path_segments: list[list[Node]]) -> Generator[Node, None, No
     """Merge in all tree branches at branch position into the path segments
     """
     finished_paths: set[int] = set()
-    
+
     for i, path in enumerate(path_segments):
         if i not in finished_paths:
             for op in path:
@@ -205,10 +190,10 @@ def get_ordered_ops(path_segments: list[list[Node]]) -> Generator[Node, None, No
                 yield op
             finished_paths.add(i)
 
-                               
+
 def get_consts(op_list: list[Node]) -> list[tuple[str, Net, float | int]]:
     """Get all const nodes in the op list
-    
+
     Returns:
         List of tuples of (name, net, value)"""
     net_lookup = {net.source: net for op in op_list for net in op.args}
@@ -218,7 +203,7 @@ def get_consts(op_list: list[Node]) -> list[tuple[str, Net, float | int]]:
 def add_read_ops(node_list: list[Node]) -> Generator[tuple[Net | None, Node], None, None]:
     """Add read operation before each op where arguments are not already positioned
     correctly in the registers
-    
+
     Returns:
         Yields tuples of a net and a operation. The net is only provided
         for new added read operations. Otherwise None is returned in the tuple."""
@@ -226,7 +211,7 @@ def add_read_ops(node_list: list[Node]) -> Generator[tuple[Net | None, Node], No
 
     # Generate result net lookup table
     net_lookup = {net.source: net for node in node_list for net in node.args}
-    
+
     for node in node_list:
         if not node.name.startswith('const_'):
             for i, net in enumerate(node.args):
@@ -238,9 +223,9 @@ def add_read_ops(node_list: list[Node]) -> Generator[tuple[Net | None, Node], No
                     new_node = Op(f"read_{net.dtype}_reg{i}_" + '_'.join(type_list), [])
                     yield net, new_node
                     registers[i] = net
-    
+
             if node in net_lookup:
-                yield None , node
+                yield None, node
                 registers[0] = net_lookup[node]
             else:
                 print('--->', node)
@@ -283,7 +268,7 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
     if isinstance(end_nodes, Node):
         node_list = [end_nodes]
     else:
-        node_list = end_nodes
+        node_list = list(end_nodes)
 
     path_segments = list(get_path_segments(node_list))
     ordered_ops = list(get_ordered_ops(path_segments))
@@ -297,10 +282,8 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
     # Get all nets associated with heap memory
     variable_list = get_nets(const_list, extended_output_ops)
 
-
     dw = binw.data_writer(sdb.byteorder)
 
-
     def variable_mem_layout(variable_list: list[Net]) -> tuple[list[tuple[Net, int, int]], int]:
         offset: int = 0
         object_list: list[tuple[Net, int, int]] = []
@@ -312,14 +295,14 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
 
         return object_list, offset
 
-
     object_list, data_section_lengths = variable_mem_layout(variable_list)
 
-    #data_section_lengths = object_list[-1][1] + object_list[-1][2]
+    # Write data
     dw.write_com(binw.Command.ALLOCATE_DATA)
     dw.write_int(data_section_lengths)
 
     for net, out_offs, lengths in object_list:
+        dw.add_variable(net, out_offs, lengths, net.dtype)
         if isinstance(net.source, Const):
             dw.write_com(binw.Command.COPY_DATA)
             dw.write_int(out_offs)
@@ -330,7 +313,7 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
     # write auxiliary_functions
     # TODO
 
-    # Prepare program data and relocations
+    # Prepare program code and relocations
     object_addr_lookp = {net: out_offs for net, out_offs, _ in object_list}
     data_list: list[bytes] = []
     patch_list: list[tuple[int, int, int]] = []
@@ -347,7 +330,7 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
         data = sdb.get_func_data(node.name)
         data_list.append(data)
         print(f"* {node.name} ({offset}) " + ' '.join(f'{d:02X}' for d in data))
-        
+
         for patch in sdb.get_patch_positions(node.name):
             assert result_net, f"Relocation found but no net defined for operation {node.name}"
             object_addr = object_addr_lookp[result_net]
@@ -383,7 +366,12 @@ def compile_to_instruction_list(end_nodes: Iterable[Node] | Node) -> binw.data_w
     dw.write_com(binw.Command.SET_ENTR_POINT)
     dw.write_int(0)
 
-    # run program command
-    dw.write_com(binw.Command.END_PROG)
-
     return dw
+
+
+def read_variable(bw: binw.data_writer, net: Net) -> None:
+    assert net in bw.variables, f"Variable {net} not found in data writer variables"
+    addr, lengths, _ = bw.variables[net]
+    bw.write_com(binw.Command.READ_DATA)
+    bw.write_int(addr)
+    bw.write_int(lengths)
diff --git a/src/copapy/binwrite.py b/src/copapy/binwrite.py
index 708c17f..8db47e4 100644
--- a/src/copapy/binwrite.py
+++ b/src/copapy/binwrite.py
@@ -1,85 +1,41 @@
 from enum import Enum
-from pelfy import elf_symbol
-from typing import Literal
+from typing import Literal, Any
 import struct
 
 
 Command = Enum('Command', [('ALLOCATE_DATA', 1), ('COPY_DATA', 2),
                            ('ALLOCATE_CODE', 3), ('COPY_CODE', 4),
                            ('PATCH_FUNC', 5), ('PATCH_OBJECT', 6),
-                           ('SET_ENTR_POINT', 64), ('END_PROG', 255)])
+                           ('SET_ENTR_POINT', 64), ('READ_DATA', 65),
+                           ('END_PROG', 255)])
 
 
-def get_variable_data(symbols: list[elf_symbol]) -> tuple[list[tuple[elf_symbol, int, int]], int]:
-    object_list: list[tuple[elf_symbol, int, int]] = []
-    out_offs = 0
-    for sym in symbols:
-        assert sym.info == 'STT_OBJECT'
-        lengths = sym.fields['st_size'],
-        object_list.append((sym, out_offs, lengths))
-        out_offs += (lengths + 3) // 4 * 4
-    return object_list, out_offs
-
-
-def get_function_data(symbols: list[elf_symbol]) -> tuple[list[tuple[elf_symbol, int, int, int]], int]:
-    code_list: list[tuple[elf_symbol, int, int, int]] = []
-    out_offs = 0
-    for sym in symbols:
-        assert sym.info == 'STT_FUNC'
-        lengths = sym.fields['st_size']
-
-        #if strip_function:
-        #    assert False, 'Not implemente'
-        # TODO: Strip functions
-        # Symbol, start out_offset in symbol, offset in output file, output lengths
-        # Set in_sym_out_offs and lengths
-        in_sym_offs = 0
-        
-        code_list.append((sym, in_sym_offs, out_offs, lengths))
-        # out_offs += (lengths + 3) // 4 * 4
-        out_offs += lengths  # should be aligned by default?
-    return code_list, out_offs
-
-
-def get_function_data_blob(symbols: list[elf_symbol]) -> tuple[list[tuple[elf_symbol, int, int, int]], int]:
-    code_list: list[tuple[elf_symbol, int, int, int]] = []
-    out_offs = 0
-    for sym in symbols:
-        assert sym.info == 'STT_FUNC'
-        lengths = sym.fields['st_size']
-
-        #if strip_function:
-        #    assert False, 'Not implemente'
-        # TODO: Strip functions
-        # Symbol, start out_offset in symbol, offset in output file, output lengths
-        # Set in_sym_out_offs and lengths
-        in_sym_offs = 0
-        
-        code_list.append((sym, in_sym_offs, out_offs, lengths))
-        out_offs += (lengths + 3) // 4 * 4
-    return code_list, out_offs
-
 class data_writer():
     def __init__(self, byteorder: Literal['little', 'big']):
         self._data: list[tuple[str, bytes, int]] = list()
-        self.byteorder = byteorder
+        self.byteorder: Literal['little', 'big'] = byteorder
+        self.variables: dict[Any, tuple[int, int, str]] = dict()
 
-    def write_int(self, value: int, num_bytes: int = 4, signed: bool = False):
+    def add_variable(self, net: Any, addr: int, lengths: int, var_type: str) -> None:
+        self.variables[net] = (addr, lengths, var_type)
+
+    def write_int(self, value: int, num_bytes: int = 4, signed: bool = False) -> None:
         self._data.append((f"INT {value}", value.to_bytes(length=num_bytes, byteorder=self.byteorder, signed=signed), 0))
 
-    def write_com(self, value: Enum, num_bytes: int = 4):
+    def write_com(self, value: Enum, num_bytes: int = 4) -> None:
         self._data.append((value.name, value.value.to_bytes(length=num_bytes, byteorder=self.byteorder, signed=False), 1))
-    
-    def write_byte(self, value: int):
+
+    def write_byte(self, value: int) -> None:
         self._data.append((f"BYTE {value}", bytes([value]), 0))
 
-    def write_bytes(self, value: bytes):
+    def write_bytes(self, value: bytes) -> None:
         self._data.append((f"BYTES {len(value)}", value, 0))
 
-    def write_value(self, value: int | float, num_bytes: int = 4):
+    def write_value(self, value: int | float, num_bytes: int = 4) -> None:
         if isinstance(value, int):
             self.write_int(value, num_bytes, True)
         else:
+            # 32 bit or 64 bit float
             en = {'little': '<', 'big': '>'}[self.byteorder]
             if num_bytes == 4:
                 data = struct.pack(en + 'f', value)
@@ -97,14 +53,6 @@ class data_writer():
     def get_data(self) -> bytes:
         return b''.join(dat for _, dat, _ in self._data)
 
-    def to_file(self, path: str):
+    def to_file(self, path: str) -> None:
         with open(path, 'wb') as f:
             f.write(self.get_data())
-
-def get_c_consts() -> str:
-    ret: list[str] = []
-    for c in Command:
-        ret.append (f"#define {c.name} {c.value}")
-    for c in PatchType:
-        ret.append(f"#define {c.name} {c.value}")
-    return '\n'.join(ret)
\ No newline at end of file
diff --git a/src/copapy/generate_stencils.py b/src/copapy/generate_stencils.py
index bfa78fe..94d229a 100644
--- a/src/copapy/generate_stencils.py
+++ b/src/copapy/generate_stencils.py
@@ -4,23 +4,27 @@ from typing import Generator
 op_signs = {'add': '+', 'sub': '-', 'mul': '*', 'div': '/'}
 
 
-def get_function_start():
+def get_function_start() -> str:
     return """
-    void function_start(){
+    int function_start(){
         result_int(0);
         asm volatile (".long 0xF27ECAFE");
+        return 1;
     }
     """
 
-def get_function_end():
+
+def get_function_end() -> str:
     return """
-    void function_end(){
+    int function_end(){
         result_int(0);
         asm volatile (".long 0xF17ECAFE");
+        return 1;
     }
     """
 
-def get_op_code(op: str, type1: str, type2: str, type_out: str):
+
+def get_op_code(op: str, type1: str, type2: str, type_out: str) -> str:
     return f"""
     void {op}_{type1}_{type2}({type1} arg1, {type2} arg2) {{
         asm volatile (".long 0xF17ECAFE");
@@ -29,19 +33,20 @@ def get_op_code(op: str, type1: str, type2: str, type_out: str):
     }}
     """
 
-def get_result_stubs1(type1: str):
+
+def get_result_stubs1(type1: str) -> str:
     return f"""
     void result_{type1}({type1} arg1);
     """
 
 
-def get_result_stubs2(type1: str, type2: str):
+def get_result_stubs2(type1: str, type2: str) -> str:
     return f"""
     void result_{type1}_{type2}({type1} arg1, {type2} arg2);
     """
 
 
-def get_read_reg0_code(type1: str, type2: str, type_out: str):
+def get_read_reg0_code(type1: str, type2: str, type_out: str) -> str:
     return f"""
     void read_{type_out}_reg0_{type1}_{type2}({type1} arg1, {type2} arg2) {{
         asm volatile (".long 0xF17ECAFE");
@@ -51,7 +56,7 @@ def get_read_reg0_code(type1: str, type2: str, type_out: str):
     """
 
 
-def get_read_reg1_code(type1: str, type2: str, type_out: str):
+def get_read_reg1_code(type1: str, type2: str, type_out: str) -> str:
     return f"""
     void read_{type_out}_reg1_{type1}_{type2}({type1} arg1, {type2} arg2) {{
         asm volatile (".long 0xF17ECAFE");
@@ -61,7 +66,7 @@ def get_read_reg1_code(type1: str, type2: str, type_out: str):
     """
 
 
-def get_write_code(type1: str):
+def get_write_code(type1: str) -> str:
     return f"""
     void write_{type1}({type1} arg1) {{
         asm volatile (".long 0xF17ECAFE");
@@ -107,7 +112,7 @@ if __name__ == "__main__":
     for t1, t2, t_out in permutate(types, types, types):
         code += get_read_reg0_code(t1, t2, t_out)
         code += get_read_reg1_code(t1, t2, t_out)
-    
+
     for t1 in types:
         code += get_write_code(t1)
 
diff --git a/src/copapy/ops.c b/src/copapy/ops.c
deleted file mode 100644
index d635d99..0000000
--- a/src/copapy/ops.c
+++ /dev/null
@@ -1,95 +0,0 @@
-//notes:
-
-
-
-
-
-
-
-//Helper functions
-void result_int(int ret1){
-    asm ("");
-}
-
-void result_float(float ret1){
-    asm ("");
-}
-
-void result_float_float(float ret1, float ret2){
-    asm ("");
-}
-
-
-//Operations
-void add_int_int(int arg1, int arg2){
-    result_int(arg1 + arg2);
-}
-
-void add_float_float(float arg1, float arg2){
-    result_float(arg1 + arg2);
-}
-
-void add_float_int(float arg1, float arg2){
-    result_float(arg1 + arg2);
-}
-
-void sub_int_int(int arg1, int arg2){
-    result_int(arg1 - arg2);
-}
-
-void sub_float_float(float arg1, float arg2){
-    result_float(arg1 - arg2);
-}
-
-void sub_float_int(float arg1, int arg2){
-    result_float(arg1 - arg2);
-}
-
-void sub_int_float(int arg1, float arg2){
-    result_float(arg1 - arg2);
-}
-
-void mul_int_int(int arg1, int arg2){
-    result_int(arg1 * arg2);
-}
-
-void mul_float_float(float arg1, float arg2){
-    result_float(arg1 * arg2);
-}
-
-void mul_float_int(float arg1, int arg2){
-    result_float(arg1 + arg2);
-}
-
-void div_int_int(int arg1, int arg2){
-    result_int(arg1 / arg2);
-}
-
-void div_float_float(float arg1, float arg2){
-    result_float(arg1 / arg2);
-}
-
-void div_float_int(float arg1, int arg2){
-    result_float(arg1 / arg2);
-}
-
-void div_int_float(int arg1, float arg2){
-    result_float(arg1 / arg2);
-}
-
-//Read global variables from heap
-int read_int_ret = 1337;
-
-void read_int(){
-    result_int(read_int_ret);
-}
-
-float read_float_ret = 1337;
-
-void read_float(){
-    result_float(read_float_ret);
-}
-
-void read_float_2(float arg1){
-    result_float_float(arg1, read_float_ret);
-}
\ No newline at end of file
diff --git a/src/copapy/stencil_db.py b/src/copapy/stencil_db.py
index 44b2f8d..8c51287 100644
--- a/src/copapy/stencil_db.py
+++ b/src/copapy/stencil_db.py
@@ -13,6 +13,7 @@ LENGTH_CALL_INSTRUCTION = 5  # x86_64
 
 RelocationType = Enum('RelocationType', [('RELOC_RELATIVE_32', 0)])
 
+
 @dataclass
 class patch_entry:
     """
@@ -21,7 +22,7 @@ class patch_entry:
     Attributes:
         addr (int): address of first byte to patch relative to the start of the symbol
         type (RelocationType): relocation type"""
-    
+
     type: RelocationType
     addr: int
     addend: int
@@ -73,13 +74,13 @@ class stencil_database():
 
         self.function_definitions = {s.name: get_ret_function_def(s) for s in self.elf.symbols
                                      if s.info == 'STT_FUNC'}
-    
+
         self.data = {s.name: strip_symbol(s.data, self.elf.byteorder) for s in self.elf.symbols
-                                            if s.info == 'STT_FUNC'}
-        
+                     if s.info == 'STT_FUNC'}
+
         self.var_size = {s.name: s.fields['st_size'] for s in self.elf.symbols
-                                            if s.info == 'STT_OBJECT'}
-        
+                         if s.info == 'STT_OBJECT'}
+
         self.byteorder: Literal['little', 'big'] = self.elf.byteorder
 
         for name in self.function_definitions.keys():
@@ -87,7 +88,6 @@ class stencil_database():
             sym.relocations
             self.elf.symbols[name].data
 
-
     def get_patch_positions(self, symbol_name: str) -> Generator[patch_entry, None, None]:
         """Return patch positions
         """
@@ -95,7 +95,7 @@ class stencil_database():
         start_index, end_index = get_stencil_position(symbol.data, symbol.file.byteorder)
 
         for reloc in symbol.relocations:
-            
+
             # address to fist byte to patch relative to the start of the symbol
             patch = translate_relocation(
                 reloc.fields['r_offset'] - symbol.fields['st_value'] - start_index,
@@ -107,8 +107,5 @@ class stencil_database():
             if patch.addr < end_index - start_index:
                 yield patch
 
-
     def get_func_data(self, name: str) -> bytes:
         return strip_symbol(self.elf.symbols[name].data, self.elf.byteorder)
-
-
diff --git a/src/copapy/stencils.c b/src/copapy/stencils.c
index 6dcd207..4a7bf4b 100644
--- a/src/copapy/stencils.c
+++ b/src/copapy/stencils.c
@@ -223,13 +223,15 @@
         asm volatile (".long 0xF27ECAFE");
     }
     
-    void function_start(){
+    int function_start(){
         result_int(0);
         asm volatile (".long 0xF27ECAFE");
+        return 1;
     }
     
-    void function_end(){
+    int function_end(){
         result_int(0);
         asm volatile (".long 0xF17ECAFE");
+        return 1;
     }
     
\ No newline at end of file
diff --git a/src/runner/runmem2.c b/src/runner/runmem2.c
index 130121b..a6995ca 100644
--- a/src/runner/runmem2.c
+++ b/src/runner/runmem2.c
@@ -14,6 +14,7 @@
 #define PATCH_FUNC 5
 #define PATCH_OBJECT 6
 #define SET_ENTR_POINT 64
+#define READ_DATA 65
 #define END_PROG 255
 
 #define PATCH_RELATIVE_32 0
@@ -132,16 +133,27 @@ int parse_commands(uint8_t *bytes){
             case SET_ENTR_POINT:
                 rel_entr_point = *(uint32_t*)bytes; bytes += 4;
                 printf("SET_ENTR_POINT rel_entr_point=%i\n", rel_entr_point);
-                entr_point = (int (*)())(executable_memory + rel_entr_point);    
+                entr_point = (int (*)())(executable_memory + rel_entr_point);  
+                
+                mark_mem_executable();
+                int ret = entr_point();
+                printf("Return value: %i\n", ret);
                 break;
             
             case END_PROG:
                 printf("END_PROG\n");
-                mark_mem_executable();
-                int ret = entr_point();
-                printf("Return value: %i\n", ret);
                 err_flag = 1;
                 break;
+
+            case READ_DATA:
+                offs = *(uint32_t*)bytes; bytes += 4;
+                size = *(uint32_t*)bytes; bytes += 4;
+                printf("READ_DATA offs=%i size=%i data=", offs, size);
+                for (uint32_t i = 0; i < size; i++) {
+                    printf("%02X ", data_memory[offs + i]);
+                }
+                printf("\n");
+                break;
             
         	default:
                 printf("Unknown command\n");
diff --git a/tests/test_ast_gen.py b/tests/test_ast_gen.py
index 93bd9a2..c908bc5 100644
--- a/tests/test_ast_gen.py
+++ b/tests/test_ast_gen.py
@@ -1,9 +1,10 @@
 from copapy import Write, const
 import copapy as rc
 
+
 def test_ast_generation():
     c1 = const(1.11)
-    c2 = const(2.22)
+    #c2 = const(2.22)
     #c3 = const(3.33)
 
     #i1 = c1 + c2
@@ -12,36 +13,31 @@ def test_ast_generation():
 
     #r1 = i1 + i3
     #r2 = i3 * i2
-
     i1 = c1 * 2
-    i2 = i1 + 3
+    r1 = i1 + 7
+    out = Write(r1)
 
-    r1 = i1 + i2
-    r2 = c2 + 4 + c1
-
-    out = [Write(r1), Write(r2)]
     print(out)
-    print('--')
+    print('-- get_path_segments:')
 
-    path_segments = list(rc.get_path_segments(out))
+    path_segments = list(rc.get_path_segments([out]))
     for p in path_segments:
         print(p)
-    print('--')
-
+    print('-- get_ordered_ops:')
     ordered_ops = list(rc.get_ordered_ops(path_segments))
     for p in path_segments:
         print(p)
-    print('--')
+    print('-- get_consts:')
 
     const_list = rc.get_consts(ordered_ops)
     for p in const_list:
         print(p)
-    print('--')
+    print('-- add_read_ops:')
 
     output_ops = list(rc.add_read_ops(ordered_ops))
     for p in output_ops:
         print(p)
-    print('--')
+    print('-- add_write_ops:')
 
     extended_output_ops = list(rc.add_write_ops(output_ops, const_list))
     for p in extended_output_ops:
@@ -50,4 +46,4 @@ def test_ast_generation():
 
 
 if __name__ == "__main__":
-    test_ast_generation()
\ No newline at end of file
+    test_ast_generation()
diff --git a/tests/test_compile.py b/tests/test_compile.py
index 3fb856f..a8aefa8 100644
--- a/tests/test_compile.py
+++ b/tests/test_compile.py
@@ -1,6 +1,9 @@
 from copapy import Write, const
-import copapy as rc
+import copapy
 import subprocess
+import struct
+from copapy import binwrite as binw
+
 
 def run_command(command: list[str], encoding: str = 'utf8') -> str:
     process = subprocess.Popen(command, stdout=subprocess.PIPE)
@@ -9,9 +12,10 @@ def run_command(command: list[str], encoding: str = 'utf8') -> str:
     assert error is None, f"Error occurred: {error.decode(encoding)}"
     return output.decode(encoding)
 
-def test_compile():
-    c1 = const(1.11)
-    c2 = const(2.22)
+
+def test_example():
+    c1 = 1.11
+    c2 = 2.22
 
     i1 = c1 * 2
     i2 = i1 + 3
@@ -19,9 +23,48 @@ def test_compile():
     r1 = i1 + i2
     r2 = c2 + 4 + c1
 
-    out = [Write(r1), Write(r2)]
+    en = {'little': '<', 'big': '>'}['little']
+    data = struct.pack(en + 'f', r1)
+    print("example r1 " + ' '.join(f'{b:02X}' for b in data))
 
-    il = rc.compile_to_instruction_list(out)
+    data = struct.pack(en + 'f', r2)
+    print("example r2 " + ' '.join(f'{b:02X}' for b in data))
+
+    # assert False
+    # example r1 7B 14 EE 40
+    # example r2 5C 8F EA 40
+
+
+def test_compile():
+
+    print(run_command(['bash', 'build.sh']))
+
+    c1 = const(4)
+    #c2 = const(2)
+
+    #i1 = c1 * 2
+    #i2 = i1 + 3
+
+    #r1 = i1 + i2
+    #r2 = c2 + 4 + c1
+
+    #out = [Write(r1), Write(r2)]
+
+    i1 = c1 * 2
+    r1 = i1 + 7
+    out = Write(r1)
+
+    il = copapy.compile_to_instruction_list(out)
+
+    #copapy.read_variable(il, i1)
+    copapy.read_variable(il, r1)
+
+    il.write_com(binw.Command.READ_DATA)
+    il.write_int(0)
+    il.write_int(36)
+
+    # run program command
+    il.write_com(binw.Command.END_PROG)
 
     print('#', il.print())
 
@@ -30,8 +73,8 @@ def test_compile():
     result = run_command(['./bin/runmem2', 'test.copapy'])
     print(result)
 
-    assert 'Return value: 0' in result
+    assert 'Return value: 1' in result
 
 
 if __name__ == "__main__":
-    test_compile()
\ No newline at end of file
+    test_compile()
diff --git a/tests/test_stencil_db.py b/tests/test_stencil_db.py
index a5bfe7a..8563935 100644
--- a/tests/test_stencil_db.py
+++ b/tests/test_stencil_db.py
@@ -1,6 +1,7 @@
 from copapy import stencil_database
 from copapy import stencil_db
 
+
 def test_list_symbols():
     sdb = stencil_database('src/copapy/obj/stencils_x86_64_O3.o')
     print('----')
@@ -18,9 +19,9 @@ def test_start_end_function():
 
         start, end = stencil_db.get_stencil_position(data, sdb.elf.byteorder)
 
-        assert start>= 0 and end >= start and end <= len(data)
+        assert start >= 0 and end >= start and end <= len(data)
 
 
 if __name__ == "__main__":
     test_list_symbols()
-    test_start_end_function()
\ No newline at end of file
+    test_start_end_function()