diff --git a/programs/boot.vc5asm b/programs/boot.vc5asm
index 0d4f51b..1448913 100644
--- a/programs/boot.vc5asm
+++ b/programs/boot.vc5asm
@@ -51,7 +51,7 @@ key_press_int:
 
     mov r0, [0x600]
     add r0, r0, VCD
-    mov r1, [KBC_CODE]
+    mov r1, [KBD_CODE]
     cmp r1, 44 ; spacebar
     mov r2, rfl
     and r2, r2, FL_EQ
diff --git a/src/assembler.cpp b/src/assembler.cpp
index 9691be3..5120a1c 100644
--- a/src/assembler.cpp
+++ b/src/assembler.cpp
@@ -12,6 +12,7 @@
 #include <ios>
 #include <memory>
 #include <print>
+#include <string>
 #include <string_view>
 #include <unordered_map>
 #include <utility>
@@ -100,7 +101,7 @@ auto Assembler::assemble_file()
             }
 
             assert(value->ty == EOT::Imm);
-            m_syms[stmt->ident] = value->as_imm();
+            m_syms[std::string(stmt->ident)] = value->as_imm();
 
         } else if (parser.next_is_align()) {
             auto stmt = parser.parse_align();
@@ -153,6 +154,11 @@ auto Assembler::assemble_file()
                 parser.try_recover();
                 continue;
             }
+
+            if (line->labels) {
+                define_labels(*line->labels);
+            }
+
             lines.push_back(std::move(line));
         }
     }
@@ -165,33 +171,36 @@ auto Assembler::assemble_file()
     m_second_pass = true;
 
     for (const auto& line : lines) {
-        std::println("[{}] = {}", m_builder.ip(), line->ident);
         assemble_line(*line);
     }
 
-    for (size_t i = 0; i < 64; i += 4) {
-        std::println("{:02x} {:02x} {:02x} {:02x}",
-            m_program[i],
-            m_program[i + 1],
-            m_program[i + 2],
-            m_program[i + 3]);
-    }
-
     return std::move(m_program);
 }
 
-void Assembler::assemble_define_labels(const std::vector<Label>& labels)
+void Assembler::define_labels(const std::vector<Label>& labels)
 {
     for (const auto& label : labels) {
         if (label.is_local) {
-            m_sublabels[label.ident] = m_builder.ip();
+            m_sublabels[label_ident(label)] = m_builder.ip();
         } else {
-            m_sublabels.clear();
-            m_syms[label.ident] = m_builder.ip();
+            m_superlabel = label.ident;
+            m_syms[std::string(label.ident)] = m_builder.ip();
         }
     }
 }
 
+auto Assembler::label_ident(const Label& label) const -> std::string
+{
+    if (not label.is_local)
+        return std::string(label.ident);
+
+    return sublabel_ident(label.ident);
+}
+auto Assembler::sublabel_ident(std::string_view ident) const -> std::string
+{
+    return std::format("{}{}", m_superlabel, ident);
+}
+
 namespace {
 
 enum class Mnemonic {
@@ -576,9 +585,9 @@ auto Assembler::eval_operand(const Expr& expr) -> std::unique_ptr<EvaledOperand>
             return std::make_unique<EO>(loc, EOT::Str, expr.as_str());
         case Expr::Ty::Mem:
         case Expr::Ty::MemWord:
-            return eval_operand_mem(expr);
+            return eval_operand_mem(*expr.as_unary());
         case Expr::Ty::MemByte: {
-            auto evaled = eval_operand_mem(expr);
+            auto evaled = eval_operand_mem(*expr.as_unary());
             switch (evaled->ty) {
                 case EOT::MemWordImm:
                     evaled->ty = EOT::MemByteImm;
@@ -587,7 +596,7 @@ auto Assembler::eval_operand(const Expr& expr) -> std::unique_ptr<EvaledOperand>
                     evaled->ty = EOT::MemByteReg;
                     break;
                 default:
-                    break;
+                    assert(false && "should be either of the above");
             }
             return evaled;
         }
@@ -631,7 +640,8 @@ auto Assembler::eval_operand_mem(const Expr& expr)
                 expr.loc, EOT::MemWordImm, op->as_imm());
         }
         case Expr::Ty::Reg:
-            return std::make_unique<EO>(expr.loc, EOT::Reg, expr.as_reg());
+            return std::make_unique<EO>(
+                expr.loc, EOT::MemWordReg, expr.as_reg());
         case Expr::Ty::Str:
         case Expr::Ty::Mem:
         case Expr::Ty::MemByte:
@@ -704,7 +714,8 @@ auto Assembler::eval_operand_to_imm(const Expr& expr)
     auto loc = expr.loc;
     switch (expr.ty) {
         case Expr::Ty::Ident: {
-            if (!m_syms.contains(expr.as_ident())) {
+            auto ident = std::string(expr.as_ident());
+            if (!m_syms.contains(ident)) {
                 if (m_second_pass) {
                     error(expr.loc,
                         std::format(
@@ -715,11 +726,12 @@ auto Assembler::eval_operand_to_imm(const Expr& expr)
                 }
             }
 
-            auto value = m_syms[expr.as_ident()];
+            auto value = m_syms[ident];
             return std::make_unique<EO>(loc, EOT::Imm, value);
         }
         case Expr::Ty::SubLabel: {
-            if (!m_sublabels.contains(expr.as_ident())) {
+            auto ident = sublabel_ident(expr.as_ident());
+            if (!m_sublabels.contains(ident)) {
                 if (m_second_pass) {
                     error(expr.loc,
                         std::format(
@@ -730,7 +742,7 @@ auto Assembler::eval_operand_to_imm(const Expr& expr)
                 }
             }
 
-            auto value = m_sublabels[expr.as_ident()];
+            auto value = m_sublabels[ident];
             return std::make_unique<EO>(loc, EOT::Imm, value);
         }
         case Expr::Ty::Reg:
@@ -908,7 +920,9 @@ auto Parser::parse_line() -> std::unique_ptr<Line>
                 error(current_loc(), "expected identifier");
                 return nullptr;
             }
-            ident = m_tok.text;
+            ident = is_local
+                ? std::string_view(m_tok.text.data() - 1, m_tok.text.size() + 1)
+                : m_tok.text;
             step();
 
             if (not eat(':')) {
diff --git a/src/assembler.hpp b/src/assembler.hpp
index 359ff7a..8773800 100644
--- a/src/assembler.hpp
+++ b/src/assembler.hpp
@@ -210,15 +210,18 @@ namespace asmer {
         auto assemble_file()
             -> std::expected<std::vector<uint8_t>, std::string>;
 
-        void assemble_define_labels(const std::vector<Label>& labels);
-        void assemble_line(const Line& line);
-
         auto ok() const -> bool
         {
             return not m_failed;
         }
 
     private:
+        void define_labels(const std::vector<Label>& labels);
+        void assemble_line(const Line& line);
+
+        auto label_ident(const Label& label) const -> std::string;
+        auto sublabel_ident(std::string_view ident) const -> std::string;
+
         auto eval_operand(const Expr& expr) -> std::unique_ptr<EvaledOperand>;
         auto eval_operand_mem(const Expr& expr)
             -> std::unique_ptr<EvaledOperand>;
@@ -237,8 +240,9 @@ namespace asmer {
         std::string_view m_text;
         std::vector<uint8_t> m_program;
         Builder m_builder;
-        std::unordered_map<std::string_view, uint16_t> m_syms {};
-        std::unordered_map<std::string_view, uint16_t> m_sublabels {};
+        std::unordered_map<std::string, uint16_t> m_syms {};
+        std::string m_superlabel {};
+        std::unordered_map<std::string, uint16_t> m_sublabels {};
         bool m_second_pass = false;
         bool m_failed = false;
     };
diff --git a/src/block_device.hpp b/src/block_device.hpp
index c925a1a..e6fdbf5 100644
--- a/src/block_device.hpp
+++ b/src/block_device.hpp
@@ -53,7 +53,8 @@ private:
 class FileDisk final : public BlockDevice {
 public:
     explicit FileDisk(fs::path file_path)
-        : m_file(file_path, std::ios_base::binary)
+        : m_file(file_path,
+              std::ios_base::binary | std::ios_base::in | std::ios_base::out)
     {
         if (not m_file) {
             throw std::invalid_argument(std::format(
diff --git a/src/main.cpp b/src/main.cpp
index 4e3ec46..2456ead 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -29,6 +29,29 @@ int main(int argc, char** argv)
     } else {
         auto disk = FileDisk(argv[1]);
 
+        auto memory_disk = MemoryDisk(128);
+        make_program(memory_disk.data());
+
+        auto file_block = std::vector<uint8_t>(BlockDevice::block_size);
+        disk.read(file_block.data(), 0);
+
+        auto memory_block = std::vector<uint8_t>(BlockDevice::block_size);
+        memory_disk.read(memory_block.data(), 0);
+
+        std::println("file           memory");
+        for (size_t i = 0; i < 64; i += 4) {
+            std::println(
+                "{:02x} {:02x} {:02x} {:02x}    {:02x} {:02x} {:02x} {:02x}",
+                file_block[i],
+                file_block[i + 1],
+                file_block[i + 2],
+                file_block[i + 3],
+                memory_block[i],
+                memory_block[i + 1],
+                memory_block[i + 2],
+                memory_block[i + 3]);
+        }
+
         auto vm = VM(*device, disk);
         vm.run();
     }