1 files changed, 44 insertions, 1 deletions
diff --git a/asm/segment.cpp b/asm/segment.cpp
index 9fb7a52..a4544f2 100644
--- a/asm/segment.cpp
+++ b/asm/segment.cpp
@@ -2,6 +2,11 @@
 
 #include "operators.h"
 
+#include <boost/endian/conversion.hpp>
+
+#include <iostream>
+#include <exception>
+
 using namespace std::string_literals;
 
 size_t Segment::getAddressOfLabel(const std::string& label)
@@ -16,9 +21,22 @@ size_t Segment::getAddressOfLabel(const std::string& label)
     return address;
    }
   }
+  i++;
  }
 
- throw std::runtime_error("Bad label: "s + label);
+ throw std::runtime_error("Error: Label |"s + label + "| not found."s);
+}
+
+size_t Segment::getAddressOfIndex(size_t index)
+{
+ if (index >= size())
+  throw std::runtime_error("Error: Index |"s + std::to_string(index) + "| not found."s);
+
+ size_t address{0};
+ for (size_t i = 0; i < index; i++) {
+  address += (*this)[i]->size();
+ }
+ return address;
 }
 
 std::vector<uint8_t> Segment::getCode()
@@ -33,9 +51,34 @@ std::vector<uint8_t> Segment::getCode()
 
 void Segment::insertAddresses()
 {
+ // insert relative addresses
+ for (size_t i = 0; i < this->size(); i++) {
+  try {
+   AddressFeature& af { dynamic_cast<AddressFeature&>(*((*this)[i]))};
+
+   if (af.relativeAddressing == false)
+    throw std::runtime_error("Error: Absolute Addressing not supported.");
+
+   int64_t target_address = getAddressOfLabel(af.label); // throws if label not found
+   int64_t start_address = getAddressOfIndex(i); // throws if out of range
+   int64_t diff = target_address - start_address;
+   uint64_t udiff = static_cast<uint64_t>(diff);
+   if (af.addr_size == 1) {
+    if (diff < -128 || diff > 127)
+     throw std::runtime_error("Error: Address too far."s);
+    af.machine_code[af.addr_offs] = static_cast<uint8_t>(udiff);
+   } else if (af.addr_size == 4) {
+    *(reinterpret_cast<uint32_t*>(af.machine_code.data() + af.addr_offs)) = boost::endian::native_to_little(static_cast<uint32_t>(udiff));
+   } else
+    throw std::runtime_error("Error: unexpected addr_size: "s + std::to_string(af.addr_size));
+  } catch (const std::bad_cast& ex) {
+   // ignore, expected for non-addressing chunks
+  }
+ }
 }
 
 void Segment::optimize()
 {
  // TODO
 }
+