--- /dev/null
+ [bits 32] ; Starts in 32 bit mode, then will drop back later.
+ org 0x4000
+entry:
+ cli
+ ; clean up 32 bit regs
+ mov eax, 0x0
+ mov ebx, 0x0
+ mov ecx, 0x0
+ mov edx, 0x0
+ mov esi, 0x0
+ mov edi, 0x0
+ mov ebp, 0x0
+ mov esp, 0x0
+
+ lgdt [gdtp]
+
+ mov ax, 0x10
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ jmp 0x8:nextp ; Clear CS bits now too
+
+nextp:
+
+ mov eax, cr0
+ xor eax, 0x1 ; Clear PE
+ mov cr0, eax
+
+ jmp 0x0:nowreal ; and jmp away
+
+
+ [bits 16]
+nowreal:
+ mov long eax, 0x0000
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ mov sp, 0xFFFF ; set up the stack
+
+ mov al, 0xAB
+ out 0x80, al
+
+ cli
+ lidt [idtp]
+
+ mov si, RETMSG
+ call disp
+
+ int 0x19 ; warm boot without clearing RAM.
+ call handload_drive ; hopefully shouldn't happen
+ ; ok, we give up
+ cli
+halt: hlt
+ jmp halt
+
+disp:
+ lodsb
+ or al, al
+ jz .done
+ mov ah, 0x0E
+ mov bx, 0x0007
+ int 0x10
+ jmp disp
+.done:
+ ret
+
+; handload_drive should be unnecessary; int 19 should take care of it for
+; us...
+handload_drive:
+ mov ax, 0x07C0
+ mov es, ax
+ mov ax, 0x0201 ; read one sector
+ mov bx, 0x0000 ; to the normal location
+ mov cx, 0x0001 ; disk sector 1
+ mov dx, 0x0080 ; drive 0
+ int 0x13
+ jc readerr
+
+ mov si, READSUCC
+ call disp
+
+ jmp 0x7C0:0x0 ; and return control to grub!
+readerr:
+ mov si, READFAIL
+ call disp
+ ret
+
+RETMSG db "SMM installer finished, booting your system of choice.",10,13,0
+READSUCC db "Read successful; rebooting into boot sector.",10,13,0
+READFAIL db "Boot disk read failure; system halted.",10,13,0
+
+
+idtp db 0xFF, 0x03, 0x00, 0x00, 0x00, 0x00
+
+gdtp dw 0x1F
+ dd gdt
+
+gdt dd 0, 0
+ dd 0x0000FFFF, 0x00009e00 ; CS
+ dd 0x0000FFFF, 0x00009300 ; DS