u/Sensitive-Can9232

when i am swithcing to 32 bit protected mode before the far jmp i am doing [bits 32] but it is giving me error on qemu if i put after the far jump then it is working fine , i want to ask why is this happening

[bits 16]

switch_to_pm:

cli

lgdt[gdt_descriptor]

mov eax , cr0

or eax , 0x1

mov cr0 , eax

[bits 32]

jmp CODE_SEG:init_pm

init_pm:

mov ax , DATA_SEG

mov ds , ax

mov ss , ax

mov es , ax

mov fs , ax

mov gs , ax

mov ebp , 0x90000

mov esp , ebp

jmp BEGIN_PM

when i am swithcing to 32 bit protected mode before the far jmp i am doing [bits 32] but it is giving me error on qemu if i put after the far jump then it is working fine , i want to ask why is this happening

[bits 16]


switch_to_pm:
    cli
    lgdt[gdt_descriptor]
    mov eax , cr0
    or eax , 0x1
    mov cr0 , eax


    [bits 32]


    jmp CODE_SEG:init_pm
    


init_pm:
    mov ax , DATA_SEG
    mov ds , ax
    mov ss , ax
    mov es , ax
    mov fs , ax
    mov gs , ax


    mov ebp , 0x90000
    mov esp , ebp


    jmp BEGIN_PM[bits 16]


switch_to_pm:
    cli
    lgdt[gdt_descriptor]
    mov eax , cr0
    or eax , 0x1
    mov cr0 , eax


    [bits 32]


    jmp CODE_SEG:init_pm
    


init_pm:
    mov ax , DATA_SEG
    mov ds , ax
    mov ss , ax
    mov es , ax
    mov fs , ax
    mov gs , ax


    mov ebp , 0x90000
    mov esp , ebp


    jmp BEGIN_PM

So from today onwards I will be documenting my os dev journey on this subredit, i have started os dev from past week as i like os a lot( thx to ostep book which was a Bible in my OS course) today I understood how does bios interrupt 0x13 is used to take data from the the disk ans then stored in the ram using ES:BX .

So i am seeing everyone is make a ai + mern project, and honestly I dont have interest in both but i like os development a lot( had a course in uni) so in this summer vacation i am going in depth os development leaning assembly, low level concept, memory management and all , but is it worth leanings, are there jobs for this role?

So i am currently a second year btech student, with summer holidays comming, i want to do core OS stuff, low level , create small project os, learn linux in depth but everyone around me is doing mern, ai/ml but i dont like that stuff. I will be doing leetcode and cp in the summer. Can anyone guide me if I am making a wrong decision.