diff --git a/ast.cpp b/ast.cpp
index 8dbfc4f..e3079d4 100644
--- a/ast.cpp
+++ b/ast.cpp
@@ -38,4 +38,11 @@ void ast_printer_t::parenthesize(const std::string_view s, const expr_t * a, con
   os << ')';
 }
 
+// instructions
+
+void ast_printer_t::visit(const op::alu_t * alu) const
+{
+  (void)alu;
+}
+
 }
diff --git a/ast.hpp b/ast.hpp
index b1d3ad2..3c0bffd 100644
--- a/ast.hpp
+++ b/ast.hpp
@@ -6,6 +6,7 @@
 #include "visitor.hpp"
 #include "expr.hpp"
 #include "num.hpp"
+#include "stmt.hpp"
 
 namespace dsp {
 
@@ -21,6 +22,35 @@ struct ast_printer_t : visitor_t<void>
   void visit(const grouping_t * grouping) const;
   void visit(const literal_t * literal) const;
 
+  void visit(const op::alu_t * alu) const;
+  void visit(const op::mov_ram_x_t * mov_ram_x) const;
+  void visit(const op::mov_mul_p_t * mov_mul_p) const;
+  void visit(const op::mov_ram_p_t * mov_ram_p) const;
+  void visit(const op::mov_ram_y_t * mov_ram_y) const;
+  void visit(const op::clr_a_t * clr_a) const;
+  void visit(const op::mov_alu_a_t * mov_alu_a) const;
+  void visit(const op::mov_ram_a_t * mov_ram_a) const;
+  void visit(const op::mov_imm_d1_t * mov_imm_) const;
+  void visit(const op::mov_ram_d1_t * mov_ram_) const;
+  void visit(const op::instruction_t * instruction) const;
+
+  void visit(const load::mvi_t * mvi) const;
+  void visit(const load::mvi_cond_t * mvi_cond) const;
+
+  void visit(const dma::ingress_imm_t * ingress_imm) const;
+  void visit(const dma::egress_imm_t * egress_imm) const;
+  void visit(const dma::ingress_ram_t * ingress_ram) const;
+  void visit(const dma::egress_ram_t * egress_ram) const;
+
+  void visit(const jump::jmp_t * jmp) const;
+  void visit(const jump::jmp_cond_t * jmp_cond) const;
+
+  void visit(const loop::btm_t * btm) const;
+  void visit(const loop::lps_t * lps) const;
+
+  void visit(const end::end_t * end) const;
+  void visit(const end::endi_t  * endi) const;
+
   void parenthesize(const std::string_view s, const expr_t * a) const;
   void parenthesize(const std::string_view s, const expr_t * a, const expr_t * b) const;
 };
diff --git a/build_radix_tree.py b/build_radix_tree.py
index e1c4648..13c72cf 100644
--- a/build_radix_tree.py
+++ b/build_radix_tree.py
@@ -111,6 +111,10 @@ reg_keywords = [
     "wa0",
     "lop",
     "top",
+    "ct0",
+    "ct1",
+    "ct2",
+    "ct3",
 ]
 
 cond_keywords = [
diff --git a/grammar.txt b/grammar.txt
index 486dbbb..aa72b1c 100644
--- a/grammar.txt
+++ b/grammar.txt
@@ -4,7 +4,7 @@ xy_src → "mc0" | "mc1" | "mc2" | "mc3"
        | "m0"  | "m1"  | "m2"  | "m3"
 
 mov_ram_x → "mov" xy_src  "," "x"
-mov_mul_p → "mov" "mul"    "," "p"
+mov_mul_p → "mov" "mul"   "," "p"
 mov_ram_p → "mov" xy_src  "," "p"
 
 x_bus → mov_ram_x | mov_mul_p | mov_ram_p
@@ -25,8 +25,8 @@ d1_src → "mc0" | "mc1" | "mc2" | "mc3"
        | "m0"  | "m1"  | "m2"  | "m3"
        | "alh" | "all"
 
-mov_imm_d1 → "mov" simm8  d1_dest
-mov_ram_d1 → "mov" d1_src d1_dest
+mov_imm_d1 → "mov" simm8  "," d1_dest
+mov_ram_d1 → "mov" d1_src "," d1_dest
 
 d1_bus → mov_imm_d1 → mov_ram_d1
 
@@ -94,7 +94,7 @@ assignment_statement → identifier "=" expression "\n"
 
 label → identifier ":"
 
-instruction_statement → label? instruction "\n"
+instruction_statement → label? instruction? "\n"
 
 statement → assignment_statement
           | instruction_statement
diff --git a/keyword.case_inc b/keyword.case_inc
index d9d9b71..e41bd03 100644
--- a/keyword.case_inc
+++ b/keyword.case_inc
@@ -8,6 +8,10 @@ case _and        : return os << "AND";
 case _btm        : return os << "BTM";
 case _c          : return os << "C";
 case _clr        : return os << "CLR";
+case _ct0        : return os << "CT0";
+case _ct1        : return os << "CT1";
+case _ct2        : return os << "CT2";
+case _ct3        : return os << "CT3";
 case _d0         : return os << "D0";
 case _dma        : return os << "DMA";
 case _dmah       : return os << "DMAH";
diff --git a/keyword.enum_inc b/keyword.enum_inc
index cba7772..82b413c 100644
--- a/keyword.enum_inc
+++ b/keyword.enum_inc
@@ -8,6 +8,10 @@ _and,
 _btm,
 _c,
 _clr,
+_ct0,
+_ct1,
+_ct2,
+_ct3,
 _d0,
 _dma,
 _dmah,
diff --git a/keyword.hpp b/keyword.hpp
index 726668b..c2dbafe 100644
--- a/keyword.hpp
+++ b/keyword.hpp
@@ -99,6 +99,25 @@ find(const std::string_view s)
           }
         }
         break;
+      case 'T': [[fallthrough]];
+      case 't':
+        if (ix < s.length()) {
+          switch (s[ix++]) {
+          case '0':
+            if (ix == s.length()) return { token_t::type_t::_ct0 };
+            break;
+          case '1':
+            if (ix == s.length()) return { token_t::type_t::_ct1 };
+            break;
+          case '2':
+            if (ix == s.length()) return { token_t::type_t::_ct2 };
+            break;
+          case '3':
+            if (ix == s.length()) return { token_t::type_t::_ct3 };
+            break;
+          }
+        }
+        break;
       }
     }
     break;
diff --git a/parser.cpp b/parser.cpp
index e117b7d..45b2232 100644
--- a/parser.cpp
+++ b/parser.cpp
@@ -12,6 +12,8 @@ primary        → NUMBER
 */
 
 #include <string>
+#include <optional>
+#include <cassert>
 
 #include "parser.hpp"
 #include "num.hpp"
@@ -152,7 +154,7 @@ expr_t * parser_t::primary()
 
   if (match(left_paren)) {
     expr_t * expr = expression();
-    consume(right_paren, "expected ')' after expression.");
+    consume(right_paren, "expected ')' after expression");
     return new grouping_t(expr);
   }
 
@@ -170,4 +172,161 @@ void parser_t::synchronize()
 }
 */
 
+std::optional<op::op_t *> parser_t::alu()
+{
+  using namespace dsp::op;
+
+  if      (match(_and)) return {new alu_t(alu_type_t::andl)};
+  else if (match(_or )) return {new alu_t(alu_type_t::orl)};
+  else if (match(_xor)) return {new alu_t(alu_type_t::xorl)};
+  else if (match(_add)) return {new alu_t(alu_type_t::add)};
+  else if (match(_sub)) return {new alu_t(alu_type_t::sub)};
+  else if (match(_ad2)) return {new alu_t(alu_type_t::ad2)};
+  else if (match(_sr )) return {new alu_t(alu_type_t::sr)};
+  else if (match(_rr )) return {new alu_t(alu_type_t::rr)};
+  else if (match(_sl )) return {new alu_t(alu_type_t::sl)};
+  else if (match(_rl )) return {new alu_t(alu_type_t::rl)};
+  else if (match(_rl8)) return {new alu_t(alu_type_t::rl8)};
+  else                  return {};
+}
+
+bool parser_t::xyd1_src()
+{
+  const bool mc = match(_mc0) || match(_mc1) || match(_mc2) || match(_mc3);
+  const bool m  = match(_m0 ) || match(_m1 ) || match(_m2 ) || match(_m3 );
+  const bool al = match(_alh) || match(_all);
+  return mc || m || al;
+}
+
+static op::xy_src_t xy_src(const token_t& token)
+{
+  using namespace dsp::op;
+
+  switch (token.type) {
+  case _mc0: return xy_src_t::mc0;
+  case _mc1: return xy_src_t::mc1;
+  case _mc2: return xy_src_t::mc2;
+  case _mc3: return xy_src_t::mc3;
+  case _m0:  return xy_src_t::m0;
+  case _m1:  return xy_src_t::m1;
+  case _m2:  return xy_src_t::m2;
+  case _m3:  return xy_src_t::m3;
+  default: assert(false); __builtin_unreachable();
+  }
+}
+
+static op::d1_src_t d1_src(const token_t& token)
+{
+  using namespace dsp::op;
+
+  switch (token.type) {
+  case _mc0: return d1_src_t::mc0;
+  case _mc1: return d1_src_t::mc1;
+  case _mc2: return d1_src_t::mc2;
+  case _mc3: return d1_src_t::mc3;
+  case _m0:  return d1_src_t::m0;
+  case _m1:  return d1_src_t::m1;
+  case _m2:  return d1_src_t::m2;
+  case _m3:  return d1_src_t::m3;
+  case _alh: return d1_src_t::alh;
+  case _all: return d1_src_t::all;
+  default: assert(false); __builtin_unreachable();
+  }
+}
+
+std::optional<op::d1_dest_t> parser_t::d1_dest()
+{
+  using namespace dsp::op;
+
+  if      (match(_rx))  return {d1_dest_t::rx};
+  else if (match(_pl))  return {d1_dest_t::pl};
+  else if (match(_ra0)) return {d1_dest_t::ra0};
+  else if (match(_wa0)) return {d1_dest_t::wa0};
+  else if (match(_lop)) return {d1_dest_t::lop};
+  else if (match(_top)) return {d1_dest_t::top};
+  else if (match(_ct0)) return {d1_dest_t::ct0};
+  else if (match(_ct1)) return {d1_dest_t::ct1};
+  else if (match(_ct2)) return {d1_dest_t::ct2};
+  else if (match(_ct3)) return {d1_dest_t::ct3};
+  else                  return {};
+}
+
+std::optional<op::op_t *> parser_t::xyd1_bus()
+{
+  if (match(_mov)) {
+    if (match(_alu)) {
+      consume(comma, "expected `,` after `mov alu`");
+      consume(_a, "expected `a` after `mov alu,`");
+      return {new op::mov_alu_a_t()};
+    } else if (match(_mul)) {
+      consume(comma, "expected ',' after `mov mul`");
+      consume(_p, "expected 'p' after `mov mul,`");
+      return {new op::mov_mul_p_t()};
+    } else if (xyd1_src()) {
+      const token_t& src_token = previous();
+      consume(comma, "expected `,` after mov src operand");
+      // this is starting to feel a bit ugly...
+      bool d1 = src_token.type == _alh || src_token.type == _alh;
+      if      (!d1 && match(_y))      return {new op::mov_ram_y_t(xy_src(src_token))};
+      else if (!d1 && match(_a))      return {new op::mov_ram_a_t(xy_src(src_token))};
+      else if (!d1 && match(_x))      return {new op::mov_ram_x_t(xy_src(src_token))};
+      else if (!d1 && match(_p))      return {new op::mov_ram_p_t(xy_src(src_token))};
+      else if (auto dest_o = d1_dest()) return {new op::mov_ram_d1_t(d1_src(src_token), *dest_o)};
+      else
+	throw error(peek(), "expected x-bus, y-bus, or d-bus destination operand");
+    } else {
+      expr_t * expr = expression();
+      simm_t<8> simm = simm_t<8>(expr);
+      if (auto dest_o = d1_dest())
+	return {new op::mov_imm_d1_t(simm, *dest_o)};
+      else
+      	throw error(peek(), "expected d1 destination operand");
+    }
+  } else if (match(_clr)) {
+    consume(_a, "expected `a` after `clr`");
+    return {new op::clr_a_t()};
+  } else {
+    return {};
+  }
+}
+
+std::optional<stmt_t *> parser_t::op()
+{
+  std::vector<const op::op_t *> ops;
+  while (true) {
+    if      (auto stmt_o = alu()     ) ops.emplace_back(*stmt_o);
+    else if (auto stmt_o = xyd1_bus()) ops.emplace_back(*stmt_o);
+    else                        break;
+  }
+  if (ops.size() != 0)
+    return {new op::instruction_t(ops)};
+  else
+    return {};
+}
+
+std::optional<stmt_t *> parser_t::instruction()
+{
+  // "nop"
+  // op
+  // load
+  // dma
+  // jump
+  // loop
+  // end
+  return {};
+}
+
+std::optional<stmt_t *> parser_t::instruction_statement()
+{
+  // label
+  // instruction
+  // newline
+  return {};
+}
+
+stmt_t * parser_t::statement()
+{
+  return nullptr;
+}
+
 }
diff --git a/parser.hpp b/parser.hpp
index efe501e..7813c6a 100644
--- a/parser.hpp
+++ b/parser.hpp
@@ -1,9 +1,11 @@
 #include <stdexcept>
 #include <string>
 #include <vector>
+#include <optional>
 
 #include "token.hpp"
 #include "expr.hpp"
+#include "stmt.hpp"
 
 namespace dsp {
 
@@ -45,6 +47,14 @@ struct parser_t
   expr_t * orl();
   expr_t * primary();
 
+  std::optional<op::op_t *> alu();
+  bool xyd1_src();
+  std::optional<op::d1_dest_t> d1_dest();
+  std::optional<op::op_t *> xyd1_bus();
+  std::optional<stmt_t *> op();
+  std::optional<stmt_t *> instruction();
+  std::optional<stmt_t *> instruction_statement();
+  stmt_t * statement();
 };
 
 }
diff --git a/stmt.hpp b/stmt.hpp
index 0c9f9aa..37b2e0a 100644
--- a/stmt.hpp
+++ b/stmt.hpp
@@ -1,5 +1,9 @@
-#include <vector>
+#pragma once
 
+#include <vector>
+#include <string>
+
+#include "stmt_enum.hpp"
 #include "expr.hpp"
 
 namespace dsp {
@@ -24,6 +28,9 @@ struct stmt_accept_t : stmt_t {
 
 template <bool S, int N>
 struct imm_t {
+  imm_t(expr_t * expr)
+    : expr(expr) {}
+
   const expr_t * expr;
 
   static constexpr bool sign = S;
@@ -38,21 +45,11 @@ using uimm_t = imm_t<false, N>;
 
 namespace op {
 
-enum alu_type_t {
-  andl,
-  orl,
-  xorl,
-  add,
-  sub,
-  ad2,
-  sr,
-  rr,
-  sl,
-  rl,
-  rl8,
+struct op_t
+{
 };
 
-struct alu_t : stmt_accept_t<alu_t>
+struct alu_t : op_t, stmt_accept_t<alu_t>
 {
   alu_t(alu_type_t type)
     : type(type) {}
@@ -60,16 +57,7 @@ struct alu_t : stmt_accept_t<alu_t>
   const alu_type_t type;
 };
 
-enum struct xy_src_t {
-  mc0, mc1, mc2, mc3,
-  m0 , m1 , m2 ,  m3,
-};
-
-struct op_t : stmt_accept_t<op_t>
-{
-};
-
-struct mov_ram_x_t : virtual op_t
+struct mov_ram_x_t : op_t, stmt_accept_t<mov_ram_x_t>
 {
   mov_ram_x_t(xy_src_t src)
     : src(src) {}
@@ -77,12 +65,12 @@ struct mov_ram_x_t : virtual op_t
   const xy_src_t src;
 };
 
-struct mov_mul_p_t : op_t
+struct mov_mul_p_t : op_t, stmt_accept_t<mov_mul_p_t>
 {
   mov_mul_p_t() {}
 };
 
-struct mov_ram_p_t : op_t
+struct mov_ram_p_t : op_t, stmt_accept_t<mov_ram_p_t>
 {
   mov_ram_p_t(xy_src_t src)
     : src(src) {}
@@ -90,7 +78,7 @@ struct mov_ram_p_t : op_t
   const xy_src_t src;
 };
 
-struct mov_ram_y_t : op_t
+struct mov_ram_y_t : op_t, stmt_accept_t<mov_ram_y_t>
 {
   mov_ram_y_t(xy_src_t src)
     : src(src) {}
@@ -98,17 +86,17 @@ struct mov_ram_y_t : op_t
   const xy_src_t src;
 };
 
-struct clr_a_t : op_t
+struct clr_a_t : op_t, stmt_accept_t<clr_a_t>
 {
   clr_a_t() {}
 };
 
-struct mov_alu_a_t : op_t
+struct mov_alu_a_t : op_t, stmt_accept_t<mov_alu_a_t>
 {
   mov_alu_a_t() {}
 };
 
-struct mov_ram_a_t : op_t
+struct mov_ram_a_t : op_t, stmt_accept_t<mov_ram_a_t>
 {
   mov_ram_a_t(xy_src_t src)
     : src(src) {}
@@ -116,30 +104,18 @@ struct mov_ram_a_t : op_t
   const xy_src_t src;
 };
 
-enum struct d1_dest_t {
-  rx , pl ,
-  ra0, wa0,
-  lop, top,
-  ct0, ct1, ct2, ct3,
-};
-
-enum struct d1_src_t {
-  mc0, mc1, mc2, mc3,
-  m0 , m1 , m2 , m3 ,
-};
-
-struct mov_imm_d1 : op_t
+struct mov_imm_d1_t : op_t, stmt_accept_t<mov_imm_d1_t>
 {
-  mov_imm_d1(simm_t<8> imm, d1_dest_t dest)
+  mov_imm_d1_t(simm_t<8> imm, d1_dest_t dest)
     : imm(imm), dest(dest) {}
 
   const simm_t<8> imm;
   const d1_dest_t dest;
 };
 
-struct mov_ram_d1 : op_t
+struct mov_ram_d1_t : op_t, stmt_accept_t<mov_ram_d1_t>
 {
-  mov_ram_d1(d1_src_t src, d1_dest_t dest)
+  mov_ram_d1_t(d1_src_t src, d1_dest_t dest)
     : src(src), dest(dest) {}
 
   const d1_src_t src;
@@ -148,31 +124,16 @@ struct mov_ram_d1 : op_t
 
 struct instruction_t : stmt_accept_t<instruction_t>
 {
-  instruction_t(std::vector<op_t *> ops)
+  instruction_t(std::vector<const op_t *> ops)
     : ops(ops) {}
 
-  const std::vector<op_t *> ops;
+  const std::vector<const op_t *> ops;
 };
 
 } // op
 
 namespace load {
 
-enum struct dest_t {
-  mc0, mc1, mc2, mc3,
-  rx , pl ,
-  ra0, wa0,
-  lop, pc ,
-};
-
-enum struct cond_t {
-  z , nz ,
-  s , ns ,
-  c , nc ,
-  t0, nt0,
-  zs, nzs,
-};
-
 struct mvi_t : stmt_accept_t<mvi_t>
 {
   mvi_t(uimm_t<25> imm)
@@ -193,26 +154,6 @@ struct mvi_cond_t : stmt_accept_t<mvi_cond_t>
 
 namespace dma {
 
-enum struct add_mode_t {
-  _0 ,
-  _1 ,
-  _2 ,
-  _4 ,
-  _8 ,
-  _16,
-  _32,
-  _64,
-};
-
-enum struct ingress_t {
-  m0, m1, m2, m3
-};
-
-enum struct egress_t {
-  m0, m1, m2, m3,
-  prg,
-};
-
 struct ingress_imm_t : stmt_accept_t<ingress_imm_t>
 {
   ingress_imm_t(bool hold, ingress_t ingress, simm_t<8> imm)
@@ -233,11 +174,6 @@ struct egress_imm_t : stmt_accept_t<egress_imm_t>
   const simm_t<8> imm;
 };
 
-enum struct length_ram_t {
-  m0 , m1 , m2 , m3 ,
-  mc0, mc1, mc2, mc3,
-};
-
 struct ingress_ram_t : stmt_accept_t<ingress_ram_t>
 {
   ingress_ram_t(bool hold, ingress_t ingress, length_ram_t ram)
@@ -263,14 +199,6 @@ struct egress_ram_t : stmt_accept_t<egress_ram_t>
 namespace jump
 {
 
-enum struct cond_t {
-  z , nz,
-  s , ns,
-  c , nc,
-  t0, nt0,
-  zs, nzs,
-};
-
 struct jmp_t : stmt_accept_t<jmp_t>
 {
   jmp_t(uimm_t<8> imm)
diff --git a/stmt_enum.hpp b/stmt_enum.hpp
new file mode 100644
index 0000000..9d14f35
--- /dev/null
+++ b/stmt_enum.hpp
@@ -0,0 +1,101 @@
+#pragma once
+
+namespace dsp {
+
+namespace op {
+
+enum struct alu_type_t : int {
+  andl,
+  orl,
+  xorl,
+  add,
+  sub,
+  ad2,
+  sr,
+  rr,
+  sl,
+  rl,
+  rl8,
+};
+
+enum struct xy_src_t {
+  mc0, mc1, mc2, mc3,
+  m0 , m1 , m2 ,  m3,
+};
+
+enum struct d1_dest_t {
+  rx , pl ,
+  ra0, wa0,
+  lop, top,
+  ct0, ct1, ct2, ct3,
+};
+
+enum struct d1_src_t {
+  mc0, mc1, mc2, mc3,
+  m0 , m1 , m2 , m3 ,
+  alh, all,
+};
+
+}
+
+namespace load {
+
+enum struct dest_t {
+  mc0, mc1, mc2, mc3,
+  rx , pl ,
+  ra0, wa0,
+  lop, pc ,
+};
+
+enum struct cond_t {
+  z , nz ,
+  s , ns ,
+  c , nc ,
+  t0, nt0,
+  zs, nzs,
+};
+
+} // load
+
+namespace dma {
+
+enum struct add_mode_t {
+  _0 ,
+  _1 ,
+  _2 ,
+  _4 ,
+  _8 ,
+  _16,
+  _32,
+  _64,
+};
+
+enum struct ingress_t {
+  m0, m1, m2, m3
+};
+
+enum struct egress_t {
+  m0, m1, m2, m3,
+  prg,
+};
+
+enum struct length_ram_t {
+  m0 , m1 , m2 , m3 ,
+  mc0, mc1, mc2, mc3,
+};
+
+} // dma
+
+namespace jump {
+
+enum struct cond_t {
+  z , nz,
+  s , ns,
+  c , nc,
+  t0, nt0,
+  zs, nzs,
+};
+
+} // jump
+
+}
diff --git a/stmt_string.cpp b/stmt_string.cpp
new file mode 100644
index 0000000..ddd2606
--- /dev/null
+++ b/stmt_string.cpp
@@ -0,0 +1,153 @@
+#pragma once
+
+#include "stmt_string.hpp"
+#include "stmt_enum.hpp"
+
+#define i(v) (static_cast<int>(v))
+
+namespace dsp {
+
+namespace op {
+
+const std::string alu_type_string[] = {
+  [i(alu_type_t::andl)] = "andl",
+  [i(alu_type_t::orl )] = "orl",
+  [i(alu_type_t::xorl)] = "xorl",
+  [i(alu_type_t::add )] = "add",
+  [i(alu_type_t::sub )] = "sub",
+  [i(alu_type_t::ad2 )] = "ad2",
+  [i(alu_type_t::sr  )] = "sr",
+  [i(alu_type_t::rr  )] = "rr",
+  [i(alu_type_t::sl  )] = "sl",
+  [i(alu_type_t::rl  )] = "rl",
+  [i(alu_type_t::rl8 )] = "rl8",
+};
+
+const std::string xy_src_string[] = {
+  [i(xy_src_t::mc0)] = "mc0",
+  [i(xy_src_t::mc1)] = "mc1",
+  [i(xy_src_t::mc2)] = "mc2",
+  [i(xy_src_t::mc3)] = "mc3",
+  [i(xy_src_t::m0 )] = "m0" ,
+  [i(xy_src_t::m1 )] = "m1" ,
+  [i(xy_src_t::m2 )] = "m2" ,
+  [i(xy_src_t::m3 )] = "m3" ,
+};
+
+const std::string d1_dest_string[] = {
+  [i(d1_dest_t::rx )] = "rx" ,
+  [i(d1_dest_t::pl )] = "pl" ,
+  [i(d1_dest_t::ra0)] = "ra0",
+  [i(d1_dest_t::wa0)] = "wa0",
+  [i(d1_dest_t::lop)] = "lop",
+  [i(d1_dest_t::top)] = "top",
+  [i(d1_dest_t::ct0)] = "ct0",
+  [i(d1_dest_t::ct1)] = "ct1",
+  [i(d1_dest_t::ct2)] = "ct2",
+  [i(d1_dest_t::ct3)] = "ct3",
+};
+
+const std::string d1_src_string[] = {
+  [i(d1_src_t::mc0)] = "mc0",
+  [i(d1_src_t::mc1)] = "mc1",
+  [i(d1_src_t::mc2)] = "mc2",
+  [i(d1_src_t::mc3)] = "mc3",
+  [i(d1_src_t::m0 )] = "m0" ,
+  [i(d1_src_t::m1 )] = "m1" ,
+  [i(d1_src_t::m2 )] = "m2" ,
+  [i(d1_src_t::m3 )] = "m3" ,
+};
+
+}
+
+namespace load {
+
+const std::string dest_string[] = {
+  [i(dest_t::mc0)] = "mc0",
+  [i(dest_t::mc1)] = "mc1",
+  [i(dest_t::mc2)] = "mc2",
+  [i(dest_t::mc3)] = "mc3",
+  [i(dest_t::rx )] = "rx" ,
+  [i(dest_t::pl )] = "pl" ,
+  [i(dest_t::ra0)] = "ra0",
+  [i(dest_t::wa0)] = "wa0",
+  [i(dest_t::lop)] = "lop",
+  [i(dest_t::pc )] = "pc" ,
+};
+
+const std::string cond_string[] = {
+  [i(cond_t::z  )] = "z" ,
+  [i(cond_t::nz )] = "nz" ,
+  [i(cond_t::s  )] = "s" ,
+  [i(cond_t::ns )] = "ns" ,
+  [i(cond_t::c  )] = "c" ,
+  [i(cond_t::nc )] = "nc" ,
+  [i(cond_t::t0 )] = "t0",
+  [i(cond_t::nt0)] = "nt0",
+  [i(cond_t::zs )] = "zs",
+  [i(cond_t::nzs)] = "nzs",
+};
+
+} // load
+
+namespace dma {
+
+const std::string add_mode_string[] = {
+  [i(add_mode_t::_0 )] = "0" ,
+  [i(add_mode_t::_1 )] = "1" ,
+  [i(add_mode_t::_2 )] = "2" ,
+  [i(add_mode_t::_4 )] = "4" ,
+  [i(add_mode_t::_8 )] = "8" ,
+  [i(add_mode_t::_16)] = "16",
+  [i(add_mode_t::_32)] = "32",
+  [i(add_mode_t::_64)] = "64",
+};
+
+const std::string ingress_string[] = {
+  [i(ingress_t::m0)] = "m0",
+  [i(ingress_t::m1)] = "m1",
+  [i(ingress_t::m2)] = "m2",
+  [i(ingress_t::m3)] = "m3"
+};
+
+const std::string egress_string[] = {
+  [i(egress_t::m0 )] = "m0",
+  [i(egress_t::m1 )] = "m1",
+  [i(egress_t::m2 )] = "m2",
+  [i(egress_t::m3 )] = "m3",
+  [i(egress_t::prg)] = "prg",
+};
+
+const std::string length_ram_string[] = {
+  [i(length_ram_t::m0 )] = "m0" ,
+  [i(length_ram_t::m1 )] = "m1" ,
+  [i(length_ram_t::m2 )] = "m2" ,
+  [i(length_ram_t::m3 )] = "m3" ,
+  [i(length_ram_t::mc0)] = "mc0",
+  [i(length_ram_t::mc1)] = "mc1",
+  [i(length_ram_t::mc2)] = "mc2",
+  [i(length_ram_t::mc3)] = "mc3",
+};
+
+} // dma
+
+namespace jump {
+
+const std::string cond_string[] = {
+  [i(cond_t::z  )] = "z" ,
+  [i(cond_t::nz )] = "nz",
+  [i(cond_t::s  )] = "s" ,
+  [i(cond_t::ns )] = "ns",
+  [i(cond_t::c  )] = "c" ,
+  [i(cond_t::nc )] = "nc",
+  [i(cond_t::t0 )] = "t0",
+  [i(cond_t::nt0)] = "nt0",
+  [i(cond_t::zs )] = "zs",
+  [i(cond_t::nzs)] = "nzs",
+};
+
+} // jump
+
+}
+
+#undef i
diff --git a/stmt_string.hpp b/stmt_string.hpp
new file mode 100644
index 0000000..5bc9d9c
--- /dev/null
+++ b/stmt_string.hpp
@@ -0,0 +1,38 @@
+#pragma once
+
+#include <string>
+
+namespace dsp {
+
+namespace op {
+
+extern const std::string alu_type_string[];
+extern const std::string xy_src_string[];
+extern const std::string d1_dest_string[];
+extern const std::string d1_src_string[];
+
+}
+
+namespace load {
+
+extern const std::string dest_string[];
+extern const std::string cond_string[];
+
+} // load
+
+namespace dma {
+
+extern const std::string add_mode_string[];
+extern const std::string ingress_string[];
+extern const std::string egress_string[];
+extern const std::string length_ram_string[];
+
+} // dma
+
+namespace jump {
+
+extern const std::string cond_string[];
+
+}
+
+}
diff --git a/visitable.hpp b/visitable.hpp
index 6ab5880..cb2e577 100644
--- a/visitable.hpp
+++ b/visitable.hpp
@@ -2,10 +2,55 @@
 
 namespace dsp {
 
+// expressions
 struct binary_t;
 struct grouping_t;
 struct literal_t;
 struct unary_t;
 struct assign_t;
 
+// instructions
+namespace op {
+struct alu_t;
+struct mov_ram_x_t;
+struct mov_ram_x_t;
+struct mov_mul_p_t;
+struct mov_ram_p_t;
+struct mov_ram_y_t;
+struct clr_a_t;
+struct mov_alu_a_t;
+struct mov_ram_a_t;
+struct mov_imm_d1_t;
+struct mov_ram_d1_t;
+struct instruction_t;
+}
+
+namespace load{
+struct mvi_t;
+struct mvi_cond_t;
+}
+
+namespace dma {
+struct ingress_imm_t;
+struct egress_imm_t;
+struct ingress_ram_t;
+struct egress_ram_t;
+}
+
+namespace jump {
+struct jmp_t;
+struct jmp_cond_t;
+}
+
+namespace loop {
+struct btm_t;
+struct lps_t;
+}
+
+namespace end {
+struct end_t;
+struct endi_t ;
+}
+
+
 }
diff --git a/visitor.hpp b/visitor.hpp
index 6bcf7e1..2966ed2 100644
--- a/visitor.hpp
+++ b/visitor.hpp
@@ -12,6 +12,36 @@ struct visitor_t
   virtual T visit(const binary_t * expr) const = 0;
   virtual T visit(const grouping_t * expr) const = 0;
   virtual T visit(const literal_t * expr) const = 0;
+
+  virtual T visit(const op::alu_t * stmt) const = 0;
+  virtual T visit(const op::mov_ram_x_t * mov_ram_x) const = 0;
+  virtual T visit(const op::mov_mul_p_t * mov_mul_p) const = 0;
+  virtual T visit(const op::mov_ram_p_t * mov_ram_p) const = 0;
+  virtual T visit(const op::mov_ram_y_t * mov_ram_y) const = 0;
+  virtual T visit(const op::clr_a_t * clr_a) const = 0;
+  virtual T visit(const op::mov_alu_a_t * mov_alu_a) const = 0;
+  virtual T visit(const op::mov_ram_a_t * mov_ram_a) const = 0;
+  virtual T visit(const op::mov_imm_d1_t * mov_imm_) const = 0;
+  virtual T visit(const op::mov_ram_d1_t * mov_ram_) const = 0;
+  virtual T visit(const op::instruction_t * instruction) const = 0;
+
+  virtual T visit(const load::mvi_t * mvi) const = 0;
+  virtual T visit(const load::mvi_cond_t * mvi_cond) const = 0;
+
+  virtual T visit(const dma::ingress_imm_t * ingress_imm) const = 0;
+  virtual T visit(const dma::egress_imm_t * egress_imm) const = 0;
+  virtual T visit(const dma::ingress_ram_t * ingress_ram) const = 0;
+  virtual T visit(const dma::egress_ram_t * egress_ram) const = 0;
+
+  virtual T visit(const jump::jmp_t * jmp) const = 0;
+  virtual T visit(const jump::jmp_cond_t * jmp_cond) const = 0;
+
+  virtual T visit(const loop::btm_t * btm) const = 0;
+  virtual T visit(const loop::lps_t * lps) const = 0;
+
+  virtual T visit(const end::end_t * end) const = 0;
+  virtual T visit(const end::endi_t  * endi) const = 0;
+
 };
 
 }