0xax
Linux Inside

Updated 6 days ago

Pino (@pinotsao) started discussion #96

a year ago · 2 comments

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Here we can see a jmp instruction opcode (0xeb) that jumps to the start_of_setup-1f point. In Nf notation, 2f refers to the following local 2: label; in our case, it is label 1 that is present right after jump, and it contains the rest of the setup header. Right after the setup header, we see the .entrytext section, which starts at the start_of_setup label.

From bootloader to kernel (Edit this file)

I think the 1f here is not jump to lable 1 in the front. It is obviously an manually hardcoded instruction

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lion-chen @lion-chen commented 2 months ago

This is a short jump instruction, so start_of_setup-1f is offset from NEXT INSTRUCTION (pc). Program will jump to pc + (start_of_setup - 1:), which is start__of__setup, as the value of register pc is address of label 1.

Pino @pinotsao commented 2 months ago

Thanks, I am aware I have wrong understanding. Thanks for your help


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