I am trying to code a small OS, and when trying to compile the assembly file into a flat binary using NASM in the WSL (Windows Subsystem For Linux), it gives me this error:

secondary_bootloader.asm:15: error: instruction not supported in 64-bit mode
secondary_bootloader.asm:17: error: instruction not supported in 64-bit mode
secondary_bootloader.asm:20: error: instruction not supported in 64-bit mode

When my code is:

[BITS 64]
[ORG 0x1000]

start:
    ; Set up the GDT (Global Descriptor Table) for 64-bit mode
    lgdt [gdt_descriptor]

    ; Enable long mode by setting the EFER.LME bit in the MSR
    mov ecx, 0xC0000080   ; MSR_EFER
    rdmsr
    or rax, 0x100         ; Set EFER.LME (Long Mode Enable) bit
    wrmsr

    ; Switch to 64-bit mode
    mov eax, cr0
    or eax, 0x80000001    ; Set PE (Protection Enable) and PG (Paging) bits
    mov cr0, eax

    ; Far jump to flush the pipeline
    jmp 0x08:protected_mode_entry

protected_mode_entry:
    ; Set up 64-bit mode segments
    mov rax, 0x2000       ; Address of the kernel
    jmp rax               ; Jump to the kernel

gdt_start:
    ; GDT entries for 64-bit mode
    dq 0x0000000000000000  ; Null descriptor
    dq 0x00CF9A000000FFFF  ; Code Segment Descriptor
    dq 0x00CF92000000FFFF  ; Data Segment Descriptor

gdt_descriptor:
    dw gdt_end - gdt_start - 1  ; Limit
    dd gdt_start               ; Base address

gdt_end:

times 510 - ($ - $$) db 0

I tried nasm -f bin secondary_bootloader.asm -o secondary_bootloader.bin and it gave me the error message. When I tried nasm -f win64 secondary_bootloader.asm -o secondary_bootloader.bin, it then gave me:

secondary_bootloader.asm:2: error: unrecognized directive [ORG]