On 13.01.2016 08:46, Andrei Borzenkov wrote: > 13.01.2016 10:26, Minyoung Go пишет: >> *Dear GNU Grub Members.* >> I found weired comments at <Grub>/grub-core/boot/i386/pc/boot.S. Comments >> in Line 221, 222 is "ljmp to the next instruction because some bogus BIOSes >> jump to 07C0:0000 instead of 0000:7C00.". However, "ljmp $0, >> $real_start" is no longer pointing to adsolute address. This comments were >> written at version 1.98, when "$real_start" point to adsolute address with >> ABS macro. Therefore I think this comments should be changed. Below is my >> idea to change that comments. >> > > You patch removes the most important information in this comment - why > this instruction is needed at all. > ljmp is still pointing to absolute address and ABS just wasn't necessary.
disassembly shows:
7c74: ea 79 7c 00 00 ljmp $0x0,$0x7c79
You can see 0000:7c79 baked in
>>
>> diff --git a/grub-core/boot/i386/pc/boot.S
>> b/grub-core/boot/i386/pc/boot.S
>>
>> index 2bd0b2d..378f960
>> 100644
>> ---
>> a/grub-core/boot/i386/pc/boot.S
>> +++
>> b/grub-core/boot/i386/pc/boot.S
>> @@ -221,8 +221,7 @@
>> boot_drive_check:
>> movb $0x80,
>> %dl
>> 1:
>>
>>
>> /*
>> - * ljmp to the next instruction because some bogus
>> BIOSes
>> - * jump to 07C0:0000 instead of
>> 0000:7C00.
>> + * ljmp to the next
>> instruction
>>
>> */
>> ljmp $0, $real_start
>>
>>
>> I will be looking forward to your reply. Thank you.
>>
>> *Best Regard, Minyoung Go.*
>> Email : hedon...@gmail.com
>>
>
>
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