1 files changed, 46 insertions, 14 deletions

diff --git a/arch/x86_64/src/kernel/main.cpp b/arch/x86_64/src/kernel/main.cpp
index 2040fe3..4deac6d 100644
--- a/arch/x86_64/src/kernel/main.cpp
+++ b/arch/x86_64/src/kernel/main.cpp
@@ -6,14 +6,28 @@
 
 namespace teachos::arch::kernel
 {
+  auto print_mem_info(basic_memory_info * mem_info) -> void
+  {
+    using namespace video::vga;
+
+    auto mem_lower = mem_info->mem_lower;
+    text::write("Lower memory (kB): ", text::common_attributes::green_on_black);
+    text::write_number(mem_lower, text::common_attributes::green_on_black);
+
+    auto mem_upper = mem_info->mem_upper;
+    text::write("Upper memory (kB): ", text::common_attributes::green_on_black);
+    text::write_number(mem_upper, text::common_attributes::green_on_black);
+  }
+
   auto print_memory_map(memory_map_info * mminfo) -> void
   {
     using namespace video::vga;
 
     uint32_t const entry_size = mminfo->entry_size;
-    uint32_t const entry_version = mminfo->entry_version;
     text::write("Entry Size: ", text::common_attributes::green_on_black);
     text::write_number(entry_size, text::common_attributes::green_on_black);
+
+    uint32_t const entry_version = mminfo->entry_version;
     text::write("Version: ", text::common_attributes::green_on_black);
     text::write_number(entry_version, text::common_attributes::green_on_black);
 
@@ -26,10 +40,13 @@ namespace teachos::arch::kernel
     {
       text::write("Base Address: ", text::common_attributes::green_on_black);
       text::write_number(entry->base_addr, text::common_attributes::green_on_black);
+
       text::write("Length: ", text::common_attributes::green_on_black);
       text::write_number(entry->length, text::common_attributes::green_on_black);
+
       text::write("Type: ", text::common_attributes::green_on_black);
       text::write_number(entry->type, text::common_attributes::green_on_black);
+
       text::write("Reserved: ", text::common_attributes::green_on_black);
       text::write_number(entry->reserved, text::common_attributes::green_on_black);
     }
@@ -42,9 +59,11 @@ namespace teachos::arch::kernel
     uint16_t const num = symbol->num;
     text::write("Number of entries: ", text::common_attributes::green_on_black);
     text::write_number(num, text::common_attributes::green_on_black);
+
     uint16_t const entsize = symbol->entsize;
     text::write("Entry Size: ", text::common_attributes::green_on_black);
     text::write_number(entsize, text::common_attributes::green_on_black);
+
     uint16_t const shndx = symbol->shndx;
     text::write("Section index: ", text::common_attributes::green_on_black);
     text::write_number(shndx, text::common_attributes::green_on_black);
@@ -56,32 +75,41 @@ namespace teachos::arch::kernel
       uint32_t const sh_name = section->sh_name;
       text::write("Section name: ", text::common_attributes::green_on_black);
       text::write_number(sh_name, text::common_attributes::green_on_black);
+
       uint32_t const sh_type = section->sh_type;
       text::write("Section type: ", text::common_attributes::green_on_black);
       text::write_number(sh_type, text::common_attributes::green_on_black);
+
       uint64_t const sh_flags = section->sh_flags;
       text::write("Section flags: ", text::common_attributes::green_on_black);
       text::write_number(sh_flags, text::common_attributes::green_on_black);
+
       uint64_t const sh_addr = section->sh_addr;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section address: ", text::common_attributes::green_on_black);
       text::write_number(sh_addr, text::common_attributes::green_on_black);
+
       uint64_t const sh_offset = section->sh_offset;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section offset: ", text::common_attributes::green_on_black);
       text::write_number(sh_offset, text::common_attributes::green_on_black);
+
       uint64_t const sh_size = section->sh_size;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section size: ", text::common_attributes::green_on_black);
       text::write_number(sh_size, text::common_attributes::green_on_black);
+
       uint32_t const sh_link = section->sh_link;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section link: ", text::common_attributes::green_on_black);
       text::write_number(sh_link, text::common_attributes::green_on_black);
+
       uint32_t const sh_info = section->sh_info;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section info: ", text::common_attributes::green_on_black);
       text::write_number(sh_info, text::common_attributes::green_on_black);
+
       uint64_t const sh_addralign = section->sh_addralign;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section address align: ", text::common_attributes::green_on_black);
       text::write_number(sh_addralign, text::common_attributes::green_on_black);
+
       uint64_t const sh_entsize = section->sh_entsize;
-      text::write("Section name: ", text::common_attributes::green_on_black);
+      text::write("Section entry size: ", text::common_attributes::green_on_black);
       text::write_number(sh_entsize, text::common_attributes::green_on_black);
     }
   }
@@ -94,20 +122,24 @@ namespace teachos::arch::kernel
     text::cursor(false);
     text::write("TeachOS is starting up...", text::common_attributes::green_on_black);
 
-    auto mip = arch::boot::multiboot_information_pointer;
-
-    // Address of the first multiboot tag
-    auto multiboot_tag = (struct multiboot_tag *)((uint8_t *)mip + 8);
+    multiboot_info * multiboot_information_pointer = (multiboot_info *)arch::boot::multiboot_information_pointer;
+    auto multiboot_tag = &(multiboot_information_pointer->tags);
 
     /*
      * Loop over the multiboot2 tags to access the information needed.
-     * Tags are defined in the header.
+     * Tags are defined in the header file and are padded so that each
+     * Tag starts at an 8-bytes aligned adress.
+     *
+     * The increment part aligns the size to an 8-byte address.
      */
     for (auto tag = multiboot_tag; tag->type != MULTIBOOT_TAG_TYPE_END;
-         tag = (struct multiboot_tag *)((uint8_t *)tag + ((tag->size + 7) & ~7)))
+         tag = (struct multiboot_tag *)(((uint8_t *)tag) + ((tag->size + 7) & ~7)))
     {
       switch (tag->type)
       {
+        case MULTIBOOT_TAG_TYPE_BASIC_MEMINFO:
+          print_mem_info((struct basic_memory_info *)tag);
+          break;
         case MULTIBOOT_TAG_TYPE_ELF_SECTIONS:
           print_elf_sections((struct elf_symbols_section *)tag);
           break;