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lib/relocator

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This commit is contained in:
Vladimir 'phcoder' Serbinenko 2009-08-03 12:48:25 +02:00
parent f84114f583
commit e7573c5ce2
9 changed files with 509 additions and 120 deletions
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75
loader/i386/multiboot_helper.S
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@ -22,81 +22,6 @@
.p2align 2 /* force 4-byte alignment */
/*
* This starts the multiboot kernel.
*/
VARIABLE(grub_multiboot_payload_size)
.long 0
VARIABLE(grub_multiboot_payload_orig)
.long 0
VARIABLE(grub_multiboot_payload_dest)
.long 0
VARIABLE(grub_multiboot_payload_entry_offset)
.long 0
/*
* The relocators below understand the following parameters:
* ecx: Size of the block to be copied.
* esi: Where to copy from (always lowest address, even if we're relocating
* backwards).
* edi: Where to copy to (likewise).
* edx: Offset of the entry point (relative to the beginning of the block).
*/
VARIABLE(grub_multiboot_forward_relocator)
/* Add entry offset. */
addl %edi, %edx
/* Forward copy. */
cld
rep
movsb
jmp *%edx
VARIABLE(grub_multiboot_forward_relocator_end)
VARIABLE(grub_multiboot_backward_relocator)
/* Add entry offset (before %edi is mangled). */
addl %edi, %edx
/* Backward movsb is implicitly off-by-one. compensate that. */
decl %esi
decl %edi
/* Backward copy. */
std
addl %ecx, %esi
addl %ecx, %edi
rep
movsb
cld
jmp *%edx
VARIABLE(grub_multiboot_backward_relocator_end)
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
/* Interrupts should be disabled. */
cli
/* Where do we copy what from. */
movl EXT_C(grub_multiboot_payload_size), %ecx
movl EXT_C(grub_multiboot_payload_orig), %esi
movl EXT_C(grub_multiboot_payload_dest), %edi
movl EXT_C(grub_multiboot_payload_entry_offset), %edx
/* Move the magic value into eax. */
movl $MULTIBOOT_MAGIC2, %eax
/* Jump to the relocator. */
popl %ebp
jmp *%ebp
/*
* This starts the multiboot 2 kernel.
*/