diff --git a/asm/asm.h b/asm/asm.h
index 2f66bd4..17fa7dc 100644
--- a/asm/asm.h
+++ b/asm/asm.h
@@ -93,6 +93,9 @@ typedef struct {
     uint16_t offset;
 } Line;
 
+uint16_t assemble_to_binary(
+    uint16_t* out, const Line* lines, size_t lines_size);
+
 Line s_label(int label);
 Line s_data_i(uint16_t data);
 Line s_data_l(int label);
@@ -166,11 +169,75 @@ Line s_rmod_r(Reg dst_reg, Reg op1_reg, Reg op2_reg);
 
 #define s_pop_r(REG) s_mov16_r_mr(REG, Rsp, 0), s_sub_i(Rsp, Rsp, 2)
 
-uint16_t assemble_to_binary(
-    uint16_t* out, const Line* lines, size_t lines_size);
-
-#define fmt_binary(VAL)                                                        \
-    (VAL) >> 7 & 1 ? '1' : '0', (VAL) >> 6 & 1 ? '1' : '0',                    \
-        (VAL) >> 5 & 1 ? '1' : '0', (VAL) >> 4 & 1 ? '1' : '0',                \
-        (VAL) >> 3 & 1 ? '1' : '0', (VAL) >> 2 & 1 ? '1' : '0',                \
-        (VAL) >> 1 & 1 ? '1' : '0', (VAL) >> 0 & 1 ? '1' : '0'
+#ifdef ASM_NO_CTOR_PREFIX
+#define label s_label
+#define data_i s_data_i
+#define data_l s_data_l
+#define nop s_nop
+#define hlt s_hlt
+#define jmp_r s_jmp_r
+#define jmp_i s_jmp_i
+#define jmp_l s_jmp_l
+#define jnz_r s_jnz_r
+#define jnz_i s_jnz_i
+#define jnz_l s_jnz_l
+#define cmp_r s_cmp_r
+#define cmp_i s_cmp_i
+#define cmp_l s_cmp_l
+#define mov8_mr_r s_mov8_mr_r
+#define mov8_mi_i s_mov8_mi_i
+#define mov8_mi_r s_mov8_mi_r
+#define mov16_r_r s_mov16_r_r
+#define mov16_r_i s_mov16_r_i
+#define mov16_r_mr s_mov16_r_mr
+#define mov16_r_mi s_mov16_r_mi
+#define mov16_r_ml s_mov16_r_ml
+#define mov16_mr_r s_mov16_mr_r
+#define mov16_ml_r s_mov16_ml_r
+#define in_i s_in_i
+#define call_i s_call_i
+#define call_l s_call_l
+#define ret s_ret
+#define lit_i s_lit_i
+#define lit_l s_lit_l
+#define int_ s_int
+#define iret s_iret
+#define or_i s_or_i
+#define xor_i s_xor_i
+#define and_i s_and_i
+#define shl_i s_shl_i
+#define rshl_i s_rshl_i
+#define shr_i s_shr_i
+#define rshr_i s_rshr_i
+#define add_i s_add_i
+#define sub_i s_sub_i
+#define rsub_i s_rsub_i
+#define mul_i s_mul_i
+#define imul_i s_imul_i
+#define div_i s_div_i
+#define idiv_i s_idiv_i
+#define rdiv_i s_rdiv_i
+#define ridiv_i s_ridiv_i
+#define mod_i s_mod_i
+#define rmod_i s_rmod_i
+#define or_r s_or_r
+#define xor_r s_xor_r
+#define and_r s_and_r
+#define shl_r s_shl_r
+#define rshl_r s_rshl_r
+#define shr_r s_shr_r
+#define rshr_r s_rshr_r
+#define add_r s_add_r
+#define sub_r s_sub_r
+#define rsub_r s_rsub_r
+#define mul_r s_mul_r
+#define imul_r s_imul_r
+#define div_r s_div_r
+#define idiv_r s_idiv_r
+#define rdiv_r s_rdiv_r
+#define ridiv_r s_ridiv_r
+#define mod_r s_mod_r
+#define rmod_r s_rmod_r
+#define push_r s_push_r
+#define pop_r s_pop_r
+#endif
diff --git a/common/fmt_binary.h b/common/fmt_binary.h
new file mode 100644
index 0000000..d5717b7
--- /dev/null
+++ b/common/fmt_binary.h
@@ -0,0 +1,7 @@
+#pragma once
+
+#define fmt_binary(VAL)                                                        \
+    (VAL) >> 7 & 1 ? '1' : '0', (VAL) >> 6 & 1 ? '1' : '0',                    \
+        (VAL) >> 5 & 1 ? '1' : '0', (VAL) >> 4 & 1 ? '1' : '0',                \
+        (VAL) >> 3 & 1 ? '1' : '0', (VAL) >> 2 & 1 ? '1' : '0',                \
+        (VAL) >> 1 & 1 ? '1' : '0', (VAL) >> 0 & 1 ? '1' : '0'