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* kern/i386/loader.S (grub_multiboot_backward_relocator): Improve

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comments.  Avoid copiing one more byte than necessary (just in case).
This commit is contained in:
robertmh 2008-11-22 15:00:39 +00:00
parent bc3a2f3115
commit 80fc88f22d
2 changed files with 17 additions and 6 deletions
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ChangeLog
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@ -5,6 +5,9 @@
(grub_vga_text_term): Use grub_vga_text_init_fini() instead of (grub_vga_text_term): Use grub_vga_text_init_fini() instead of
grub_vga_text_cls(). grub_vga_text_cls().
* kern/i386/loader.S (grub_multiboot_backward_relocator): Improve
comments. Avoid copiing one more byte than necessary (just in case).
2008-11-20 Robert Millan <rmh@aybabtu.com> 2008-11-20 Robert Millan <rmh@aybabtu.com>
* kern/i386/coreboot/init.c (grub_time_tics): Remove variable. * kern/i386/coreboot/init.c (grub_time_tics): Remove variable.

20
kern/i386/loader.S
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@ -141,24 +141,32 @@ VARIABLE(grub_multiboot_payload_entry_offset)
* edx: Offset of the entry point (relative to the beginning of the block). * edx: Offset of the entry point (relative to the beginning of the block).
*/ */
VARIABLE(grub_multiboot_forward_relocator) VARIABLE(grub_multiboot_forward_relocator)
cld /* Add entry offset. */
addl %edi, %edx addl %edi, %edx
/* Forward copy. */
cld
rep rep
movsb movsb
jmp *%edx jmp *%edx
VARIABLE(grub_multiboot_forward_relocator_end) VARIABLE(grub_multiboot_forward_relocator_end)
VARIABLE(grub_multiboot_backward_relocator) 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 std
addl %ecx, %esi addl %ecx, %esi
addl %ecx, %edi addl %ecx, %edi
/* backward movsb is implicitly off-by-one. compensate that. */
incl %ecx
rep rep
movsb movsb
/* same problem again. */
incl %edi
addl %edi, %edx
jmp *%edx jmp *%edx
VARIABLE(grub_multiboot_backward_relocator_end) VARIABLE(grub_multiboot_backward_relocator_end)