grub/kern/i386/loader.S

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ArmAsm
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2007-10-17 20:04:23 +00:00
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2005,2006,2007 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Note: These functions defined in this file may be called from C.
* Be careful of that you must not modify some registers. Quote
* from gcc-2.95.2/gcc/config/i386/i386.h:
1 for registers not available across function calls.
These must include the FIXED_REGISTERS and also any
registers that can be used without being saved.
The latter must include the registers where values are returned
and the register where structure-value addresses are passed.
Aside from that, you can include as many other registers as you like.
ax,dx,cx,bx,si,di,bp,sp,st,st1,st2,st3,st4,st5,st6,st7,arg
{ 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
*/
/*
* Note: GRUB is compiled with the options -mrtd and -mregparm=3.
* So the first three arguments are passed in %eax, %edx, and %ecx,
* respectively, and if a function has a fixed number of arguments
* and the number if greater than three, the function must return
* with "ret $N" where N is ((the number of arguments) - 3) * 4.
*/
/*
* This is the area for all of the special variables.
*/
.p2align 2 /* force 4-byte alignment */
/*
* void grub_linux_boot_zimage (void)
*/
VARIABLE(grub_linux_prot_size)
.long 0
VARIABLE(grub_linux_tmp_addr)
.long 0
VARIABLE(grub_linux_real_addr)
.long 0
FUNCTION(grub_linux_boot_zimage)
/* copy the kernel */
movl EXT_C(grub_linux_prot_size), %ecx
addl $3, %ecx
shrl $2, %ecx
movl $GRUB_LINUX_BZIMAGE_ADDR, %esi
movl $GRUB_LINUX_ZIMAGE_ADDR, %edi
cld
rep
movsl
FUNCTION(grub_linux_boot_bzimage)
call EXT_C(grub_dl_unload_all)
movl EXT_C(grub_linux_real_addr), %ebx
/* copy the real mode code */
movl EXT_C(grub_linux_tmp_addr), %esi
movl %ebx, %edi
movl $GRUB_LINUX_SETUP_MOVE_SIZE, %ecx
cld
rep
movsb
/* change %ebx to the segment address */
shrl $4, %ebx
movl %ebx, %eax
addl $0x20, %eax
movw %ax, linux_setup_seg
/* XXX new stack pointer in safe area for calling functions */
movl $0x4000, %esp
call EXT_C(grub_stop_floppy)
/* final setup for linux boot */
call prot_to_real
.code16
cli
movw %bx, %ss
movw $GRUB_LINUX_SETUP_STACK, %sp
movw %bx, %ds
movw %bx, %es
movw %bx, %fs
movw %bx, %gs
/* ljmp */
.byte 0xea
.word 0
linux_setup_seg:
.word 0
.code32
/*
* This starts the multiboot kernel.
*/
FUNCTION(grub_multiboot_real_boot)
/* Push the entry address on the stack. */
pushl %eax
/* Move the address of the multiboot information structure to ebx. */
movl %edx,%ebx
/* Unload all modules and stop the floppy driver. */
call EXT_C(grub_dl_unload_all)
call EXT_C(grub_stop_floppy)
/* Interrupts should be disabled. */
cli
/* Move the magic value into eax and jump to the kernel. */
movl $MULTIBOOT_MAGIC2,%eax
popl %ecx
jmp *%ecx
/*
* This starts the multiboot 2 kernel.
*/
FUNCTION(grub_multiboot2_real_boot)
/* Push the entry address on the stack. */
pushl %eax
/* Move the address of the multiboot information structure to ebx. */
movl %edx,%ebx
/* Unload all modules and stop the floppy driver. */
call EXT_C(grub_dl_unload_all)
call EXT_C(grub_stop_floppy)
/* Interrupts should be disabled. */
cli
/* Move the magic value into eax and jump to the kernel. */
movl $MULTIBOOT2_BOOTLOADER_MAGIC,%eax
popl %ecx
jmp *%ecx