Adding support for Xen for x86 (32bit and 64bit)

portable/GCC/XEN_x86/x86-64/asm_src/header.asm

@@ -0,0 +1,53 @@
+ ; header
+ ; 
+ ; Copyright (C) 2025 Advanced Micro Devices, Inc. or its affiliates. All Rights Reserved.
+ ;
+ ; SPDX-License-Identifier: MIT
+ ;
+ ; Permission is hereby granted, free of charge, to any person obtaining a copy of
+ ; this software and associated documentation files (the "Software"), to deal in
+ ; the Software without restriction, including without limitation the rights to
+ ; use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ ; the Software, and to permit persons to whom the Software is furnished to do so,
+ ; subject to the following conditions:
+ ;
+ ; The above copyright notice and this permission notice shall be included in all
+ ; copies or substantial portions of the Software.
+ ;
+ ; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ ; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ ; FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ ; COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ ; IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ ; CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ ;
+
+MB2_ARCH  EQU 0                                 ; 0 = x86/x86-64
+MB2_LEN   EQU (mbend-mbhead)
+MB2_MAGIC EQU 0xe85250d6
+
+section .multiboot_header align=4096
+mbhead:
+        dd MB2_MAGIC                            ; Multiboot2 magic number
+        dd MB2_ARCH                             ; Architecture
+        dd MB2_LEN                              ; Multiboot header length
+        dd 0x100000000 - MB2_LEN - MB2_ARCH - MB2_MAGIC
+                                                ; Checksum
+
+mb2_tag_info_start:
+        dw 1                                    ; multiboot information request
+        dw 0
+        dd mb2_tag_info_end - mb2_tag_info_start
+        dd 1
+        dd 2
+        dd 6
+mb2_tag_info_end:
+
+        align 8
+mb2_tag_end_start:
+        dw 0                                    ; last tag
+        dw 0
+        dd mb2_tag_end_end - mb2_tag_end_start
+mb2_tag_end_end:
+
+mbend: