diff --git a/.clang-tidy b/.clang-tidy
new file mode 100644
index 0000000..e380b8c
--- /dev/null
+++ b/.clang-tidy
@@ -0,0 +1,8 @@
+Checks: '
+  , clang-analyzer-*
+  , cppcoreguidelines-*
+  , -cppcoreguidelines-avoid-magic-numbers
+  , -cppcoreguidelines-pro-bounds-constant-array-index
+  , -cppcoreguidelines-macro-usage
+  , -cppcoreguidelines-avoid-const-or-ref-data-members
+'
\ No newline at end of file
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
new file mode 100644
index 0000000..a759924
--- /dev/null
+++ b/.github/workflows/main.yml
@@ -0,0 +1,28 @@
+name: matar
+on: [push, pull_request, workflow_dispatch]
+
+env:
+  BUILDDIR: build
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v20
+        with:
+          extra_nix_config: |
+            auto-optimise-store = true
+            experimental-features = nix-command flakes
+
+      - name: meson build
+        run: nix develop -c meson setup $BUILDDIR
+
+      - name: clang-format check
+        run: nix develop -c ninja clang-format-check -C $BUILDDIR
+
+      - name: clang-tidy check
+        run: nix develop -c ninja clang-tidy -C $BUILDDIR
+
+      - name: ninja compile
+        run: nix develop -c ninja -C $BUILDDIR
diff --git a/apps/target/main.cc b/apps/target/main.cc
index 2efe183..3a5d692 100644
--- a/apps/target/main.cc
+++ b/apps/target/main.cc
@@ -8,10 +8,12 @@
 #include <memory>
 #include <vector>
 
+// NOLINTBEGIN
+
 int
 main(int argc, const char* argv[]) {
     std::vector<uint8_t> rom;
-    std::array<uint8_t, Memory::BIOS_SIZE> bios;
+    std::array<uint8_t, Memory::BIOS_SIZE> bios = { 0 };
 
     auto usage = [argv]() {
         std::cerr << "Usage: " << argv[0] << " <file> [-b <bios>]" << std::endl;
@@ -85,3 +87,5 @@ main(int argc, const char* argv[]) {
     }
     return 0;
 }
+
+// NOLINTEND
diff --git a/flake.nix b/flake.nix
index 6eaa4af..fe03bc4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -8,7 +8,7 @@
       systems = [
         "x86_64-linux"
         "aarch64-linux"
-        "i686-linux"
+ #       "i686-linux"
       ];
       eachSystem = with nixpkgs.lib; f: foldAttrs mergeAttrs { }
         (map (s: mapAttrs (_: v: { ${s} = v; }) (f s)) systems);
@@ -53,10 +53,6 @@
             packages = nativeBuildInputs ++ (with pkgs; [
               # dev tools
               clang-tools_16
-
-              # other tools
-              valgrind
-              llvm.lldb
             ]);
           };
           default = matar;
diff --git a/include/cpu/utility.hh b/include/cpu/utility.hh
index a790ebd..dcee945 100644
--- a/include/cpu/utility.hh
+++ b/include/cpu/utility.hh
@@ -40,6 +40,12 @@ enum class Condition {
     AL = 0b1110
 };
 
+// https://fmt.dev/dev/api.html#std-ostream-support
+std::ostream&
+operator<<(std::ostream& os, const Condition cond);
+template<>
+struct fmt::formatter<Condition> : ostream_formatter {};
+
 enum class OpCode {
     AND = 0b0000,
     EOR = 0b0001,
@@ -68,6 +74,6 @@ enum class ShiftType {
 
 // https://fmt.dev/dev/api.html#std-ostream-support
 std::ostream&
-operator<<(std::ostream& os, const Condition cond);
+operator<<(std::ostream& os, const ShiftType cond);
 template<>
-struct fmt::formatter<Condition> : ostream_formatter {};
+struct fmt::formatter<ShiftType> : ostream_formatter {};
diff --git a/src/cpu/cpu.cc b/src/cpu/cpu.cc
index 9873fbc..d2097da 100644
--- a/src/cpu/cpu.cc
+++ b/src/cpu/cpu.cc
@@ -7,10 +7,10 @@
 using namespace logger;
 
 Cpu::Cpu(Bus& bus)
-  : gpr(0)
+  : bus(std::make_shared<Bus>(bus))
+  , gpr({ 0 })
   , cpsr(0)
   , spsr(0)
-  , bus(std::make_shared<Bus>(bus))
   , gpr_banked({ { 0 }, { 0 }, { 0 }, { 0 }, { 0 }, { 0 } })
   , spsr_banked({ 0, 0, 0, 0, 0 }) {
     cpsr.set_mode(Mode::System);
@@ -18,20 +18,25 @@ Cpu::Cpu(Bus& bus)
     cpsr.set_fiq_disabled(true);
     cpsr.set_state(State::Arm);
     log_info("CPU successfully initialised");
+
+    // PC is always two instructions ahead in the pipeline
+    pc += 2 * ARM_INSTRUCTION_SIZE;
 }
 
 /* change modes */
 void
-Cpu::chg_mode(Mode from, Mode to) {
+Cpu::chg_mode(const Mode to) {
+    Mode from = cpsr.mode();
+
     if (from == to)
         return;
 
 /* TODO: replace visible registers with view once I understand how to
  * concatenate views */
 #define STORE_BANKED(mode, MODE)                                               \
-    std::copy(gpr + GPR_##MODE##_BANKED_FIRST,                                 \
-              gpr + GPR_##MODE##_BANKED_FIRST + GPR_##MODE##_BANKED_COUNT,     \
-              gpr_banked.mode)
+    std::copy(gpr.begin() + GPR_##MODE##_FIRST,                                \
+              gpr.begin() + GPR_COUNT - 1,                                     \
+              gpr_banked.mode.begin())
 
     switch (from) {
         case Mode::Fiq:
@@ -66,9 +71,9 @@ Cpu::chg_mode(Mode from, Mode to) {
     }
 
 #define RESTORE_BANKED(mode, MODE)                                             \
-    std::copy(gpr_banked.mode,                                                 \
-              gpr_banked.mode + GPR_##MODE##_BANKED_COUNT,                     \
-              gpr + GPR_##MODE##_BANKED_FIRST)
+    std::copy(gpr_banked.mode.begin(),                                         \
+              gpr_banked.mode.end(),                                           \
+              gpr.begin() + GPR_##MODE##_FIRST)
 
     switch (to) {
         case Mode::Fiq:
@@ -109,11 +114,15 @@ Cpu::chg_mode(Mode from, Mode to) {
 
 void
 Cpu::step() {
-    uint32_t insn = 0xffffffff;
+    uint32_t cur_pc = pc - 2 * ARM_INSTRUCTION_SIZE;
 
     if (cpsr.state() == State::Arm) {
-        std::string disassembled = exec_arm(insn);
-        log_info("{:#010X} : {}", gpr[15], disassembled);
-        gpr[15] += ARM_INSTRUCTION_SIZE;
+        log_info("{:#034b}", bus->read_word(cur_pc));
+
+        std::string disassembled = exec_arm(bus->read_word(cur_pc));
+
+        log_info("{:#010X} : {}", cur_pc, disassembled);
+
+        pc += ARM_INSTRUCTION_SIZE;
     }
 }
diff --git a/src/cpu/cpu.hh b/src/cpu/cpu.hh
index c329417..83af397 100644
--- a/src/cpu/cpu.hh
+++ b/src/cpu/cpu.hh
@@ -13,40 +13,32 @@ class Cpu {
     void step();
 
   private:
-    static constexpr size_t GPR_FIQ_BANKED_FIRST = 8;
-    static constexpr size_t GPR_FIQ_BANKED_COUNT = 7;
+    static constexpr size_t GPR_COUNT = 16;
 
-    static constexpr size_t GPR_SVC_BANKED_FIRST = 13;
-    static constexpr size_t GPR_SVC_BANKED_COUNT = 2;
+    static constexpr size_t GPR_FIQ_FIRST     = 8;
+    static constexpr size_t GPR_SVC_FIRST     = 13;
+    static constexpr size_t GPR_ABT_FIRST     = 13;
+    static constexpr size_t GPR_IRQ_FIRST     = 13;
+    static constexpr size_t GPR_UND_FIRST     = 13;
+    static constexpr size_t GPR_SYS_USR_FIRST = 8;
 
-    static constexpr size_t GPR_ABT_BANKED_FIRST = 13;
-    static constexpr size_t GPR_ABT_BANKED_COUNT = 2;
-
-    static constexpr size_t GPR_IRQ_BANKED_FIRST = 13;
-    static constexpr size_t GPR_IRQ_BANKED_COUNT = 2;
-
-    static constexpr size_t GPR_UND_BANKED_FIRST = 13;
-    static constexpr size_t GPR_UND_BANKED_COUNT = 2;
-
-    static constexpr size_t GPR_SYS_USR_BANKED_FIRST = 8;
-    static constexpr size_t GPR_SYS_USR_BANKED_COUNT = 7;
-
-    static constexpr size_t GPR_VISIBLE_COUNT = 16;
-
-    uint32_t gpr[GPR_VISIBLE_COUNT]; // general purpose registers
-    Psr cpsr;                        // current program status register
-    Psr spsr;                        // status program status register
     std::shared_ptr<Bus> bus;
+    std::array<uint32_t, GPR_COUNT> gpr; // general purpose registers
+
+    Psr cpsr; // current program status register
+    Psr spsr; // status program status register
+
+    uint32_t& pc = gpr[15];
 
     struct {
-        uint32_t fiq[GPR_FIQ_BANKED_COUNT];
-        uint32_t svc[GPR_SVC_BANKED_COUNT];
-        uint32_t abt[GPR_ABT_BANKED_COUNT];
-        uint32_t irq[GPR_IRQ_BANKED_COUNT];
-        uint32_t und[GPR_UND_BANKED_COUNT];
+        std::array<uint32_t, GPR_COUNT - GPR_FIQ_FIRST - 1> fiq;
+        std::array<uint32_t, GPR_COUNT - GPR_SVC_FIRST - 1> svc;
+        std::array<uint32_t, GPR_COUNT - GPR_ABT_FIRST - 1> abt;
+        std::array<uint32_t, GPR_COUNT - GPR_IRQ_FIRST - 1> irq;
+        std::array<uint32_t, GPR_COUNT - GPR_UND_FIRST - 1> und;
 
         // visible registers before the mode switch
-        uint32_t old[GPR_SYS_USR_BANKED_COUNT];
+        std::array<uint32_t, GPR_COUNT - GPR_SYS_USR_FIRST> old;
     } gpr_banked; // banked general purpose registers
 
     struct {
@@ -57,6 +49,6 @@ class Cpu {
         Psr und;
     } spsr_banked; // banked saved program status registers
 
-    void chg_mode(Mode from, Mode to);
-    std::string exec_arm(uint32_t insn);
+    void chg_mode(const Mode to);
+    std::string exec_arm(const uint32_t insn);
 };
diff --git a/src/cpu/instruction.cc b/src/cpu/instruction.cc
index 261c94b..b93d331 100644
--- a/src/cpu/instruction.cc
+++ b/src/cpu/instruction.cc
@@ -5,25 +5,27 @@
 #include <cstdint>
 
 using namespace logger;
+using std::array;
+using stringv = std::string_view;
 
 std::string
-Cpu::exec_arm(uint32_t insn) {
+Cpu::exec_arm(const uint32_t insn) {
     Condition cond = static_cast<Condition>(get_bit_range(insn, 28, 31));
     std::string disassembled;
 
-    auto pc_error = [](uint8_t r, const char* syn) {
+    auto pc_error = [](uint8_t r, stringv syn) {
         if (r == 15)
             log_error("Using PC (R15) as operand in {}", syn);
     };
 
-    auto pc_undefined = [](uint8_t r, const char* syn) {
+    auto pc_undefined = [](uint8_t r, stringv syn) {
         if (r == 15)
             log_warn("Using PC (R15) as operand in {}", syn);
     };
 
     // Branch and exhcange
     if ((insn & 0x0FFFFFF0) == 0x012FFF10) {
-        static constexpr char syn[] = "BX";
+        static constexpr stringv syn = "BX";
 
         uint8_t rn = insn & 0b1111;
 
@@ -38,16 +40,16 @@ Cpu::exec_arm(uint32_t insn) {
             cpsr.set_state(state);
 
             // copy to PC
-            gpr[15] = gpr[rn];
+            pc = gpr[rn];
 
             // ignore [1:0] bits for arm and 0 bit for thumb
-            rst_nth_bit(gpr[15], 0);
+            rst_nth_bit(pc, 0);
             if (state == State::Arm)
-                rst_nth_bit(gpr[15], 1);
+                rst_nth_bit(pc, 1);
         }
         // Branch
     } else if ((insn & 0x0E000000) == 0x0A000000) {
-        static constexpr char syn[] = "B";
+        static constexpr stringv syn = "B";
 
         bool link       = get_nth_bit(insn, 24);
         uint32_t offset = get_bit_range(insn, 0, 23);
@@ -63,14 +65,14 @@ Cpu::exec_arm(uint32_t insn) {
                 offset |= 0xFC000000;
 
             if (link)
-                gpr[14] = gpr[15] - ARM_INSTRUCTION_SIZE;
+                gpr[14] = pc - ARM_INSTRUCTION_SIZE;
 
-            gpr[15] += offset;
+            pc += offset - ARM_INSTRUCTION_SIZE;
         }
 
         // Multiply
     } else if ((insn & 0x0FC000F0) == 0x00000090) {
-        static constexpr char syn[2][4] = { "MUL", "MLA" };
+        static constexpr array<stringv, 2> syn = { "MUL", "MLA" };
 
         uint8_t rm = get_bit_range(insn, 0, 3);
         uint8_t rs = get_bit_range(insn, 8, 11);
@@ -117,8 +119,9 @@ Cpu::exec_arm(uint32_t insn) {
         }
         // Multiply long
     } else if ((insn & 0x0F8000F0) == 0x00800090) {
-        static constexpr char syn[2][2][6] = { { "SMULL", "SMLAL" },
-                                               { "UMULL", "UMLAL" } };
+        static constexpr array<array<stringv, 2>, 2> syn = {
+            { { "SMULL", "SMLAL" }, { "UMULL", "UMLAL" } }
+        };
 
         uint8_t rm   = get_bit_range(insn, 0, 3);
         uint8_t rs   = get_bit_range(insn, 8, 11);
@@ -157,7 +160,7 @@ Cpu::exec_arm(uint32_t insn) {
                 gpr[rdhi] = get_bit_range(eval, 32, 63);
 
             } else {
-                int64_t eval = static_cast<uint64_t>(gpr[rm]) *
+                int64_t eval = static_cast<int64_t>(gpr[rm]) *
                                  static_cast<int64_t>(gpr[rs]) +
                                (a ? static_cast<int64_t>(gpr[rdhi]) << 32 |
                                       static_cast<int64_t>(gpr[rdlo])
@@ -178,7 +181,7 @@ Cpu::exec_arm(uint32_t insn) {
 
         // Single data swap
     } else if ((insn & 0x0FB00FF0) == 0x01000090) {
-        static constexpr char syn[] = "SWP";
+        static constexpr stringv syn = "SWP";
 
         uint8_t rm = get_bit_range(insn, 0, 3);
         uint8_t rd = get_bit_range(insn, 12, 15);
@@ -206,32 +209,32 @@ Cpu::exec_arm(uint32_t insn) {
         // TODO: create abstraction to reuse for block data and single data
         // transfer
     } else if ((insn & 0x0E000090) == 0x00000090) {
-        static constexpr char syn[2][4] = { "STR", "LDR" };
+        static constexpr array<stringv, 2> syn_ = { "STR", "LDR" };
 
-        uint8_t rm = get_bit_range(insn, 0, 3);
-        uint8_t h  = get_nth_bit(insn, 5);
-        uint8_t s  = get_nth_bit(insn, 6);
-        uint8_t rd = get_bit_range(insn, 12, 15);
-        uint8_t rn = get_bit_range(insn, 16, 19);
-        bool l     = get_nth_bit(insn, 20);
-        bool w     = get_nth_bit(insn, 21);
-        bool imm   = get_nth_bit(insn, 22);
-        bool u     = get_nth_bit(insn, 23);
-        bool p     = get_nth_bit(insn, 24);
-        uint32_t offset;
+        uint8_t rm      = get_bit_range(insn, 0, 3);
+        uint8_t h       = get_nth_bit(insn, 5);
+        uint8_t s       = get_nth_bit(insn, 6);
+        uint8_t rd      = get_bit_range(insn, 12, 15);
+        uint8_t rn      = get_bit_range(insn, 16, 19);
+        bool l          = get_nth_bit(insn, 20);
+        bool w          = get_nth_bit(insn, 21);
+        bool imm        = get_nth_bit(insn, 22);
+        bool u          = get_nth_bit(insn, 23);
+        bool p          = get_nth_bit(insn, 24);
+        uint32_t offset = 0;
+
+        std::string syn =
+          fmt::format("{}{}{}", syn_[l], (s ? "S" : ""), (h ? 'H' : 'B'));
 
         if (!p && w)
-            log_error("Write-back enabled with post-indexing in {}", syn[l]);
+            log_error("Write-back enabled with post-indexing in {}", syn);
 
         if (s && !l)
-            log_error("Signed data found in {}", syn[l]);
+            log_error("Signed data found in {}", syn);
 
         if (w)
-            pc_error(rn, syn[l]);
-        pc_error(rm, syn[l]);
-
-        if (rd == 15 && !l && s && h)
-            ;
+            pc_error(rn, syn);
+        pc_error(rm, syn);
 
         {
             offset = (imm ? get_bit_range(insn, 8, 11) << 4 | rm : gpr[rm]);
@@ -241,8 +244,8 @@ Cpu::exec_arm(uint32_t insn) {
                                                  (imm ? offset : rm));
 
             disassembled = fmt::format(
-              "{}{}{}{} R{:d}{}",
-              syn[l],
+              "{}{}{}{} R{:d},{}",
+              syn_[l],
               cond,
               (s ? "S" : ""),
               (h ? 'H' : 'B'),
@@ -254,7 +257,10 @@ Cpu::exec_arm(uint32_t insn) {
         }
 
         if (cpsr.condition(cond)) {
-            uint32_t address = (u ? gpr[rn] + offset : gpr[rn] - offset);
+            uint32_t address = gpr[rn];
+
+            if (p)
+                address += (u ? offset : -offset);
 
             // load
             if (l) {
@@ -287,7 +293,92 @@ Cpu::exec_arm(uint32_t insn) {
                     bus->write_halfword(address, gpr[rd]);
                 }
             }
+
+            if (!p)
+                address += (u ? offset : -offset);
+
+            if (!p || w)
+                gpr[rn] = address;
         }
+
+        // Software Interrupt
+        // What to do here?
+    } else if ((insn & 0x0F000000) == 0x0F000000) {
+        static constexpr stringv syn = "SWI";
+
+        if (cpsr.condition(cond)) {
+            chg_mode(Mode::Supervisor);
+            pc   = 0x08;
+            spsr = cpsr;
+        }
+
+        disassembled = fmt::format("{}{} 0", syn, cond);
+
+        // Coprocessor data transfer
+    } else if ((insn & 0x0E000000) == 0x0C000000) {
+        static constexpr array<stringv, 2> syn = { "STC", "LDC" };
+
+        [[maybe_unused]] uint8_t offset = get_bit_range(insn, 0, 7);
+        uint8_t cpn                     = get_bit_range(insn, 8, 11);
+        uint8_t crd                     = get_bit_range(insn, 12, 15);
+        [[maybe_unused]] uint8_t rn     = get_bit_range(insn, 16, 19);
+        bool l                          = get_nth_bit(insn, 20);
+        [[maybe_unused]] bool w         = get_nth_bit(insn, 21);
+        bool n                          = get_nth_bit(insn, 22);
+        [[maybe_unused]] bool u         = get_nth_bit(insn, 23);
+        [[maybe_unused]] bool p         = get_nth_bit(insn, 24);
+
+        disassembled = fmt::format(
+          "{}{}{} p{},c{},{}", syn[l], cond, (n ? "L" : ""), cpn, crd, "a.");
+
+        log_error("Unimplemented instruction: {}", syn[l]);
+
+        // Coprocessor data operation
+    } else if ((insn & 0x0F000010) == 0x0E000000) {
+        static constexpr stringv syn = "CDP";
+
+        uint8_t crm    = get_bit_range(insn, 0, 4);
+        uint8_t cp     = get_bit_range(insn, 5, 7);
+        uint8_t cpn    = get_bit_range(insn, 8, 11);
+        uint8_t crd    = get_bit_range(insn, 12, 15);
+        uint8_t crn    = get_bit_range(insn, 16, 19);
+        uint8_t cp_opc = get_bit_range(insn, 20, 23);
+
+        disassembled = fmt::format("{}{} p{},{},c{},c{},c{},{}",
+                                   syn,
+                                   cond,
+                                   cpn,
+                                   cp_opc,
+                                   crd,
+                                   crn,
+                                   crm,
+                                   cp);
+
+        log_error("Unimplemented instruction: {}", syn);
+
+        // Coprocessor register transfer
+    } else if ((insn & 0x0F000010) == 0x0E000010) {
+        static constexpr array<stringv, 2> syn = { "MCR", "MRC" };
+
+        uint8_t crm    = get_bit_range(insn, 0, 4);
+        uint8_t cp     = get_bit_range(insn, 5, 7);
+        uint8_t cpn    = get_bit_range(insn, 8, 11);
+        uint8_t rd     = get_bit_range(insn, 12, 15);
+        uint8_t crn    = get_bit_range(insn, 16, 19);
+        bool l         = get_nth_bit(insn, 20);
+        uint8_t cp_opc = get_bit_range(insn, 21, 23);
+
+        disassembled = fmt::format("{}{} p{},{},c{},c{},c{},{}",
+                                   syn[l],
+                                   cond,
+                                   cpn,
+                                   cp_opc,
+                                   rd,
+                                   crn,
+                                   crm,
+                                   cp);
+
+        log_error("Unimplemented instruction: {}", syn[l]);
     }
 
     return disassembled;
diff --git a/src/cpu/psr.cc b/src/cpu/psr.cc
index c34df55..5128baf 100644
--- a/src/cpu/psr.cc
+++ b/src/cpu/psr.cc
@@ -2,9 +2,8 @@
 #include "util/bits.hh"
 #include "util/log.hh"
 
-Psr::Psr(uint32_t raw) {
-    psr = raw & PSR_CLEAR_RESERVED;
-}
+Psr::Psr(uint32_t raw)
+  : psr(raw & PSR_CLEAR_RESERVED) {}
 
 Mode
 Psr::mode() const {
diff --git a/src/cpu/utility.cc b/src/cpu/utility.cc
index 25c9861..9c17af9 100644
--- a/src/cpu/utility.cc
+++ b/src/cpu/utility.cc
@@ -32,3 +32,23 @@ operator<<(std::ostream& os, const Condition cond) {
 
     return os;
 }
+
+std::ostream&
+operator<<(std::ostream& os, const ShiftType shift_type) {
+
+#define CASE(type)                                                             \
+    case ShiftType::type:                                                      \
+        os << #type;                                                           \
+        break;
+
+    switch (shift_type) {
+        CASE(LSL)
+        CASE(LSR)
+        CASE(ASR)
+        CASE(ROR)
+    }
+
+#undef CASE
+
+    return os;
+}
diff --git a/src/cpu/utility.hh b/src/cpu/utility.hh
index a790ebd..dcee945 100644
--- a/src/cpu/utility.hh
+++ b/src/cpu/utility.hh
@@ -40,6 +40,12 @@ enum class Condition {
     AL = 0b1110
 };
 
+// https://fmt.dev/dev/api.html#std-ostream-support
+std::ostream&
+operator<<(std::ostream& os, const Condition cond);
+template<>
+struct fmt::formatter<Condition> : ostream_formatter {};
+
 enum class OpCode {
     AND = 0b0000,
     EOR = 0b0001,
@@ -68,6 +74,6 @@ enum class ShiftType {
 
 // https://fmt.dev/dev/api.html#std-ostream-support
 std::ostream&
-operator<<(std::ostream& os, const Condition cond);
+operator<<(std::ostream& os, const ShiftType cond);
 template<>
-struct fmt::formatter<Condition> : ostream_formatter {};
+struct fmt::formatter<ShiftType> : ostream_formatter {};
diff --git a/src/header.hh b/src/header.hh
index 11aae03..4e454d3 100644
--- a/src/header.hh
+++ b/src/header.hh
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstdint>
+#include <string>
 #include <vector>
 
 typedef struct {
@@ -33,9 +34,9 @@ typedef struct {
     };
 
     uint32_t entrypoint;
-    char title[12];
+    std::string title;
+    std::string title_code;
     UniqueCode unique_code;
-    char title_code[2];
     I18n i18n;
     uint8_t version;
     BootMode multiboot;
diff --git a/src/memory.cc b/src/memory.cc
index c1edcd2..e1e8a5f 100644
--- a/src/memory.cc
+++ b/src/memory.cc
@@ -10,14 +10,14 @@ using namespace logger;
 Memory::Memory(std::array<uint8_t, BIOS_SIZE>&& bios,
                std::vector<uint8_t>&& rom) noexcept
   : bios(std::move(bios))
-  , board_wram(0)
-  , chip_wram(0)
-  , palette_ram(0)
-  , vram(0)
-  , oam_obj_attr(0)
+  , board_wram({ 0 })
+  , chip_wram({ 0 })
+  , palette_ram({ 0 })
+  , vram({ 0 })
+  , oam_obj_attr({ 0 })
   , rom(std::move(rom)) {
-    std::string bios_hash = crypto::sha256(bios.data(), bios.size());
-    static constexpr char expected_hash[] =
+    std::string bios_hash = crypto::sha256(this->bios);
+    static constexpr std::string_view expected_hash =
       "fd2547724b505f487e6dcb29ec2ecff3af35a841a77ab2e85fd87350abd36570";
 
     if (bios_hash != expected_hash) {
@@ -137,7 +137,7 @@ Memory::parse_header() {
         log_info("HEADER: BIOS debugger bits not set to 0");
 
     // game info
-    std::copy(&rom[0xA0], &rom[0xA0 + 12], header.title);
+    header.title = std::string(&rom[0xA0], &rom[0xA0 + 12]);
 
     switch (rom[0xAC]) {
         case 'A':
@@ -172,8 +172,7 @@ Memory::parse_header() {
             log_error("HEADER: invalid unique code: {}", rom[0xAC]);
     }
 
-    header.title_code[0] = rom[0xAD];
-    header.title_code[1] = rom[0xAE];
+    header.title_code = std::string(&rom[0xAD], &rom[0xAE]);
 
     switch (rom[0xAF]) {
         case 'J':
diff --git a/src/memory.hh b/src/memory.hh
index 98120c8..9262a68 100644
--- a/src/memory.hh
+++ b/src/memory.hh
@@ -29,7 +29,7 @@ class Memory {
 
 #define DECL_MEMORY(name, ident, start, end)                                   \
     MEMORY_REGION(name, start, end)                                            \
-    uint8_t ident[name##_END - name##_START + 1];
+    std::array<uint8_t, name##_END - name##_START + 1> ident;
 
     MEMORY_REGION(BIOS, 0x00000000, 0x00003FFF)
     std::array<uint8_t, BIOS_SIZE> bios;
diff --git a/src/meson.build b/src/meson.build
index 28c6153..7381d51 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -3,7 +3,6 @@ lib_sources = files(
   'bus.cc'
 )
 
-subdir('util')
 subdir('cpu')
 
 fmt = dependency('fmt', version : '>=10.1.0')
diff --git a/src/util/log.hh b/src/util/log.hh
index 3e7e270..8ecd504 100644
--- a/src/util/log.hh
+++ b/src/util/log.hh
@@ -3,54 +3,55 @@
 #include <fmt/ostream.h>
 #include <iostream>
 
-namespace logger {
-inline std::ostream& stream = std::clog;
+using fmt::print;
+using std::clog;
 
+namespace logger {
 namespace ansi {
-static constexpr char RED[]     = "\033[31m";
-static constexpr char YELLOW[]  = "\033[33m";
-static constexpr char MAGENTA[] = "\033[35m";
-static constexpr char WHITE[]   = "\033[37m";
-static constexpr char BOLD[]    = "\033[1m";
-static constexpr char RESET[]   = "\033[0m";
+static constexpr std::string_view RED     = "\033[31m";
+static constexpr std::string_view YELLOW  = "\033[33m";
+static constexpr std::string_view MAGENTA = "\033[35m";
+static constexpr std::string_view WHITE   = "\033[37m";
+static constexpr std::string_view BOLD    = "\033[1m";
+static constexpr std::string_view RESET   = "\033[0m";
 }
 
 template<typename... Args>
 inline void
 log_raw(const fmt::format_string<Args...>& fmt, Args&&... args) {
-    fmt::println(stream, fmt, std::forward<Args>(args)...);
+    fmt::println(clog, fmt, std::forward<Args>(args)...);
 }
 
 template<typename... Args>
 inline void
 log_debug(const fmt::format_string<Args...>& fmt, Args&&... args) {
-    fmt::print(stream, "{}{}[DEBUG] ", ansi::MAGENTA, ansi::BOLD);
+    print(clog, "{}{}[DEBUG] ", ansi::MAGENTA, ansi::BOLD);
     log_raw(fmt, std::forward<Args>(args)...);
-    fmt::print(stream, ansi::RESET);
+    print(clog, ansi::RESET);
 }
 
 template<typename... Args>
 inline void
 log_info(const fmt::format_string<Args...>& fmt, Args&&... args) {
-    fmt::print(stream, "{}[INFO] ", ansi::WHITE);
+    print(clog, "{}[INFO] ", ansi::WHITE);
     log_raw(fmt, std::forward<Args>(args)...);
-    fmt::print(stream, ansi::RESET);
+    print(clog, ansi::RESET);
 }
 
 template<typename... Args>
 inline void
 log_warn(const fmt::format_string<Args...>& fmt, Args&&... args) {
-    fmt::print(stream, "{}[WARN] ", ansi::YELLOW);
+    print(clog, "{}[WARN] ", ansi::YELLOW);
     log_raw(fmt, std::forward<Args>(args)...);
-    fmt::print(stream, ansi::RESET);
+    print(clog, ansi::RESET);
 }
 
 template<typename... Args>
 inline void
 log_error(const fmt::format_string<Args...>& fmt, Args&&... args) {
-    fmt::print(stream, "{}{}[ERROR] ", ansi::RED, ansi::BOLD);
+    print(clog, "{}{}[ERROR] ", ansi::RED, ansi::BOLD);
     log_raw(fmt, std::forward<Args>(args)...);
-    fmt::print(stream, ansi::RESET);
+    print(clog, ansi::RESET);
 }
 }
 
diff --git a/src/util/meson.build b/src/util/meson.build
deleted file mode 100644
index 41c0f08..0000000
--- a/src/util/meson.build
+++ /dev/null
@@ -1,3 +0,0 @@
-lib_sources += files(
-  'utils.cc'
-)
\ No newline at end of file
diff --git a/src/util/utils.cc b/src/util/utils.cc
deleted file mode 100644
index cf6731c..0000000
--- a/src/util/utils.cc
+++ /dev/null
@@ -1,113 +0,0 @@
-#include "utils.hh"
-#include <bit>
-#include <iomanip>
-#include <sstream>
-#include <vector>
-
-namespace crypto {
-
-using std::rotr;
-
-std::string
-sha256(const uint8_t* data, const size_t size) {
-    // Assuming 1 byte = 8 bits
-    std::stringstream string;
-    size_t k = 512 - (size * 8 + 65) % 512;
-    size_t L = size + (65 + k) / 8;
-    size_t i, j;
-    bool c = 0;
-
-    static constexpr uint32_t K[64] = {
-        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
-        0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
-        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
-        0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
-        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
-        0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
-        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
-        0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
-        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
-        0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
-        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
-    };
-
-    uint32_t h[8] = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
-                      0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 };
-
-    for (i = 0; i < L; i += 64) {
-        size_t n = (size > i ? size - i : 0);
-        uint32_t h0[8];
-        uint32_t w[64] = { 0 };
-
-        if (n == 64)
-            c = 1;
-
-        if (n >= 64) {
-            for (j = 0; j < 16; j++) {
-                w[j] = data[i + j * 4] << 24 | data[i + j * 4 + 1] << 16 |
-                       data[i + j * 4 + 2] << 8 | data[i + j * 4 + 3];
-            }
-        } else {
-            uint8_t cur[64] = { 0 };
-
-            if (n) {
-                std::copy(data + i, data + size, cur);
-                cur[n] = 0x80;
-            } else if (c) {
-                cur[n] = 0x80;
-            }
-
-            if (n < 54) {
-                for (j = 56; j < 64; j++) {
-                    cur[j] = (size * 8 >> ((63 - j) * 8)) & 0xFF;
-                }
-            }
-
-            for (j = 0; j < 16; j++) {
-                w[j] = cur[j * 4] << 24 | cur[j * 4 + 1] << 16 |
-                       cur[j * 4 + 2] << 8 | cur[j * 4 + 3];
-            }
-        }
-
-        for (j = 16; j < 64; j++) {
-            uint32_t s0 =
-              rotr(w[j - 15], 7) ^ rotr(w[j - 15], 18) ^ (w[j - 15] >> 3);
-            uint32_t s1 =
-              rotr(w[j - 2], 17) ^ rotr(w[j - 2], 19) ^ (w[j - 2] >> 10);
-
-            w[j] = w[j - 16] + w[j - 7] + s0 + s1;
-        }
-
-        std::copy(h, h + 8, h0);
-
-        for (j = 0; j < 64; j++) {
-            uint32_t s1  = rotr(h0[4], 6) ^ rotr(h0[4], 11) ^ rotr(h0[4], 25);
-            uint32_t ch  = (h0[4] & h0[5]) ^ (~h0[4] & h0[6]);
-            uint32_t t1  = h0[7] + s1 + ch + K[j] + w[j];
-            uint32_t s0  = rotr(h0[0], 2) ^ rotr(h0[0], 13) ^ rotr(h0[0], 22);
-            uint32_t maj = (h0[0] & h0[1]) ^ (h0[0] & h0[2]) ^ (h0[1] & h0[2]);
-            uint32_t t2  = s0 + maj;
-
-            h0[7] = h0[6];
-            h0[6] = h0[5];
-            h0[5] = h0[4];
-            h0[4] = h0[3] + t1;
-            h0[3] = h0[2];
-            h0[2] = h0[1];
-            h0[1] = h0[0];
-            h0[0] = t1 + t2;
-        }
-
-        for (j = 0; j < 8; j++)
-            h[j] += h0[j];
-    }
-
-    string << std::hex << std::setfill('0');
-
-    for (j = 0; j < 8; j++)
-        for (i = 0; i < 4; i++)
-            string << std::setw(2) << ((h[j] >> (24 - i * 8)) & 0xFF);
-
-    return string.str();
-}
-}
diff --git a/src/util/utils.hh b/src/util/utils.hh
index 4731768..60819e9 100644
--- a/src/util/utils.hh
+++ b/src/util/utils.hh
@@ -1,10 +1,121 @@
 #pragma once
 
+#include <array>
+#include <bit>
+#include <fmt/core.h>
+#include <iomanip>
+#include <sstream>
 #include <string>
 
 // Why I wrote this myself? I do not know
 // I will off myself 😹😹😹😹
 namespace crypto {
+
+using std::rotr;
+
+template<typename std::size_t N>
 std::string
-sha256(const uint8_t* data, const size_t size);
+sha256(std::array<uint8_t, N>& data) {
+    // Assuming 1 byte = 8 bits
+    std::string string;
+    size_t k = 512 - (N * 8 + 65) % 512;
+    size_t L = N + (65 + k) / 8;
+    size_t i = 0, j = 0;
+    bool c = 0;
+
+    static constexpr std::array<uint32_t, 64> K = {
+        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
+        0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
+        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
+        0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
+        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
+        0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
+        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
+        0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
+        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
+        0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
+        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
+    };
+
+    std::array<uint32_t, 8> h = { 0x6a09e667, 0xbb67ae85, 0x3c6ef372,
+                                  0xa54ff53a, 0x510e527f, 0x9b05688c,
+                                  0x1f83d9ab, 0x5be0cd19 };
+
+    for (i = 0; i < L; i += 64) {
+        size_t n = (N > i ? N - i : 0);
+
+        std::array<uint32_t, 8> h0 = { 0 };
+        std::array<uint32_t, 64> w = { 0 };
+
+        if (n == 64)
+            c = 1;
+
+        if (n >= 64) {
+            for (j = 0; j < 16; j++) {
+                w[j] = data[i + j * 4] << 24 | data[i + j * 4 + 1] << 16 |
+                       data[i + j * 4 + 2] << 8 | data[i + j * 4 + 3];
+            }
+        } else {
+            std::array<uint32_t, 64> cur = { 0 };
+
+            if (n) {
+                std::copy(data.begin() + i, data.begin() + N, cur.begin());
+                cur[n] = 0x80;
+            } else if (c) {
+                cur[n] = 0x80;
+            }
+
+            if (n < 54) {
+                for (j = 56; j < 64; j++) {
+                    cur[j] = (N * 8 >> ((63 - j) * 8)) & 0xFF;
+                }
+            }
+
+            for (j = 0; j < 16; j++) {
+                w[j] = cur[j * 4] << 24 | cur[j * 4 + 1] << 16 |
+                       cur[j * 4 + 2] << 8 | cur[j * 4 + 3];
+            }
+        }
+
+        for (j = 16; j < 64; j++) {
+            uint32_t s0 =
+              rotr(w[j - 15], 7) ^ rotr(w[j - 15], 18) ^ (w[j - 15] >> 3);
+            uint32_t s1 =
+              rotr(w[j - 2], 17) ^ rotr(w[j - 2], 19) ^ (w[j - 2] >> 10);
+
+            w[j] = w[j - 16] + w[j - 7] + s0 + s1;
+        }
+
+        std::copy(h.begin(), h.end(), h0.begin());
+
+        for (j = 0; j < 64; j++) {
+            uint32_t s1  = rotr(h0[4], 6) ^ rotr(h0[4], 11) ^ rotr(h0[4], 25);
+            uint32_t ch  = (h0[4] & h0[5]) ^ (~h0[4] & h0[6]);
+            uint32_t t1  = h0[7] + s1 + ch + K[j] + w[j];
+            uint32_t s0  = rotr(h0[0], 2) ^ rotr(h0[0], 13) ^ rotr(h0[0], 22);
+            uint32_t maj = (h0[0] & h0[1]) ^ (h0[0] & h0[2]) ^ (h0[1] & h0[2]);
+            uint32_t t2  = s0 + maj;
+
+            h0[7] = h0[6];
+            h0[6] = h0[5];
+            h0[5] = h0[4];
+            h0[4] = h0[3] + t1;
+            h0[3] = h0[2];
+            h0[2] = h0[1];
+            h0[1] = h0[0];
+            h0[0] = t1 + t2;
+        }
+
+        for (j = 0; j < 8; j++)
+            h[j] += h0[j];
+    }
+
+    for (j = 0; j < 8; j++)
+        for (i = 0; i < 4; i++)
+            fmt::format_to(std::back_inserter(string),
+                           "{:02x}",
+                           ((h[j] >> (24 - i * 8)) & 0xFF));
+
+    return string;
+}
 }