Add x86_64 kernel bring-up with build-selected platform adapters

src/boot/boot.multiboot.pas

@@ -0,0 +1,75 @@
+//  Copyright 2021 Kieron Morris & Aaron Hance
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+
+{ Multiboot v1 wire layout: fixed-width fields on every architecture. }
+unit boot.multiboot;
+interface
+const MULTIBOOT_BOOTLOADER_MAGIC = $2BADB002;
+type
+        Pelf_section_header_table_t = ^elf_section_header_table_t;
+        elf_section_header_table_t = packed record
+          num: uint32;
+          size: uint32;
+          addr: uint32;
+          shndx: uint32;
+        end;
+
+        Pmultiboot_info_t = ^multiboot_info_t;
+        multiboot_info_t = packed record
+          flags: uint32;
+          mem_lower: uint32;
+          mem_upper: uint32;
+          boot_device: uint32;
+          cmdline: uint32;
+          mods_count: uint32;
+          mods_addr: uint32;
+          elf_sec: elf_section_header_table_t;
+          mmap_length: uint32;
+          mmap_addr: uint32;
+          drives_legnth : uint32;
+          drives_addr: uint32;
+          config_table : uint32;
+          boot_loader_name : uint32;
+          apm_table: uint32;
+          vbe_control_info : uint32;
+          vbe_mode_info : uint32;
+          vbe_mode : uint16;
+          vbe_interface_seg : uint16;
+          vbe_interface_off : uint16;
+          vbe_interface_len : uint16;
+          framebuffer_addr  : uint64;
+          framebuffer_pitch : uint32;
+          framebuffer_width : uint32;
+          framebuffer_height: uint32;
+          framebuffer_bpp : uint8;
+        end;
+
+        Pmodule_t = ^module_t;
+        module_t = packed record
+          mod_start: uint32;
+          mod_end: uint32;
+          name: uint32;
+          reserved: uint32;
+        end;
+
+        Pmemory_map_t = ^memory_map_t;
+        memory_map_t = packed record
+          size: uint32;
+		      base_addr : uint64;
+		      length : uint64;
+		      mtype: uint32;
+        end;
+
+implementation
+end.