From aafdcb825d5e0a73e9747162e1c4ce23660ec437 Mon Sep 17 00:00:00 2001
From: acevest <zhaoyanbai@126.com>
Date: Thu, 1 Jan 2026 11:34:15 +0800
Subject: [PATCH] =?utf8?q?=E7=A7=BB=E9=99=A4multiboot.S=E5=AF=B9=E5=AE=8F?=
 =?utf8?q?=E5=AE=9A=E4=B9=89KRNLADDR=E7=9A=84=E4=BE=9D=E8=B5=96?=
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---
 boot/multiboot.S | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/boot/multiboot.S b/boot/multiboot.S
index 839b2f3..98d2b53 100644
--- a/boot/multiboot.S
+++ b/boot/multiboot.S
@@ -14,8 +14,8 @@
  *--------------------------------------------------------------------------
  */
 #define ASM
+
 #include "boot.h"
-#include "system.h"
 #include "task.h"
 
 .global kernel_entry
@@ -25,6 +25,7 @@
 .extern setup_kernel
 .extern root_task
 .extern root_task_entry
+.extern kernel_virtual_addr_start
 
 #define MULTIBOOT_STACK_SIZE 0x4000
 
@@ -60,14 +61,11 @@ real_kernel_entry:
 
     # Save Multiboot Infomation...
     pushl   %eax
-    addl    $KRNLADDR,%ebx
+    addl    $kernel_virtual_addr_start,%ebx
     pushl   %ebx
 
     call boot_paging
 
-    #movl    $init_pgd-KRNLADDR,%ebx
-    #movl    %ebx,%cr3
-
     # enable PG WP
     movl    %cr0,%eax
     orl     $0x80010000,%eax
@@ -76,9 +74,19 @@ real_kernel_entry:
     jmp     4f
 4:
     # 准备切保护模式
+
     # 此时esp的地址还需要再调整一下
-    addl    $KRNLADDR, %esp
-    ljmp    $0x08,$p_label+KRNLADDR
+    addl    $kernel_virtual_addr_start, %esp
+
+
+    # 由于编译器不支持下面这种写法
+    # ljmp    $0x08, $p_label + kernel_virtual_addr_start
+
+    # 所以采用下面的方法跳转
+    leal    p_label,%eax
+    addl    $kernel_virtual_addr_start, %eax
+    movl    %eax, p_label_far_ptr
+    ljmp    *p_label_far_ptr
 
 p_label:
     leal    check_kernel, %eax
@@ -98,6 +106,12 @@ p_label:
 die:
     jmp     die    # Should never come to here.
 
+
+.align 4
+p_label_far_ptr:
+    .long   0x00
+    .word   0x08, 0x00
+
 .align 32
 boot_gdt:
 empty: .long    0x00000000, 0x00000000
@@ -108,4 +122,4 @@ boot_gdtr:
     boot_gdtr_limit: .word boot_gdt_end-boot_gdt
     boot_gdtr_base:  .long boot_gdt
 
-    .comm stack, MULTIBOOT_STACK_SIZE
+.comm stack, MULTIBOOT_STACK_SIZE
-- 
2.47.0