"Microsoft-style operating system in C using low-level protected mode programming"

#include <stdint.h>

struct module_header {
  uint32_t signature;
  uint32_t image_size;
  uint32_t relocation_table_offset;
  uint32_t relocation_count;
};

struct relocation_entry {
  uint32_t virtual_address;
  uint32_t symbol_table_index;
};

void *load_module(void *module_ptr) {
  struct module_header *header = (struct module_header *)module_ptr;
  if (header->signature != 0x5A4D) { // "MZ" in little-endian
    return NULL;
  }

  void *image = malloc(header->image_size);
  if (!image) {
    return NULL;
  }

  memcpy(image, module_ptr, header->image_size);

  struct relocation_entry *relocation_table = (struct relocation_entry *)((uint8_t *)module_ptr + header->relocation_table_offset);
  for (uint32_t i = 0; i < header->relocation_count; i++) {
    struct relocation_entry *relocation = &relocation_table[i];
    uint32_t *location = (uint32_t *)((uint8_t *)image + relocation->virtual_address);
    uint32_t symbol = resolve_symbol(relocation->symbol_table_index);
    *location += symbol;
  }

  return image;
}