Add C code for enabling paging in bootloader

[nameless-os.git] / boot / x86 / stage3 / loader.s

diff --git a/boot/x86/stage3/loader.s b/boot/x86/stage3/loader.s
index 0ca0ea6012591eaea6b0c573bfb7edb961b65eb1..9ed71021c5d42b291033df366f9231f3b8522b44 100644 (file)
--- a/boot/x86/stage3/loader.s
+++ b/boot/x86/stage3/loader.s
@@ -1,7 +1,11 @@
 bits 16
 cpu 686
-org 0x1800
 
+extern enable_paging
+extern map_range
+extern set_up_page_directory
+
+section .text
 %include "../fat32/fat32-structs.s"
 
 %macro print 1
@@ -11,7 +15,11 @@ org 0x1800
        pop si
 %endmacro
 
+extern __STACK_BOTTOM__
+
+global _start
 _start:
+       mov sp, __STACK_BOTTOM__
        mov [BOOT_DRIVE], dl
        call enable_unreal
        print begin
@@ -65,6 +73,11 @@ _start:
        print kernel_loaded
        
        call get_e820_map
+       mov ebx, ecx
+       mov eax, 24
+       mul ecx
+       add eax, 20
+       sub sp, ax
 
        cli
        lgdt [gdt]
@@ -147,7 +160,6 @@ memcpy:
        pop esi
        ret
 
-
 %include "unreal.s"
 %include "a20.s"
 %include "../fat32/fat32.s"
@@ -155,8 +167,9 @@ memcpy:
 %include "print.s"
 %include "e820.s"
 
-in_protected:
 bits 32
+section .text
+in_protected:
        mov ax, 0x10
        mov ds, ax
        mov es, ax
@@ -164,13 +177,46 @@ bits 32
        mov fs, ax
        mov gs, ax
 
-       call load_paging_structs
+       push dword 0
+       push 0xc0003000
+       push 0xc0000000
+       push 0x103000
+       push 0x100000
+       call map_range
+       cmp eax, 0
+       jne .error
+       add esp, 20
+       push dword 2
+       push 0xc0009000
+       push 0xc0003000
+       push 0x109000
+       push 0x103000
+       call map_range
+       cmp eax, 0
+       jne .error
+       add esp, 20
+       push dword 2
+       push 0x100000
+       push dword 0
+       push 0x100000
+       push dword 0
+       call map_range
+       cmp eax, 0
+       jne .error
+       add esp, 20
+
+       call set_up_page_directory
        call enable_paging
 
-       call 0xc0000000
+       jmp 0xc0000000
+       nop
+.error:
+       mov dword [0xb8000], 0xcf28cf3a
        hlt
        jmp $-1
 
+section .rodata
+
 kernel_name: db "KERNEL  BIN"
 begin: db "Nameless Bootloader revision ", GIT_REVISION, 0xd, 0xa, 0
 a20_enabled: db "A20 has been enabled", 0xd, 0xa, "Searching for kernel...", 0xd, 0xa, 0
@@ -193,5 +239,3 @@ ss_s: db "SS: ", 0
 space: db " ", 0
 hex_delm: db "0x", 0
 newline: db 0xd, 0xa, 0
-
-%include "paging.s"