limine/common/lib/spinup.asm64u

section .rodata

invalid_idt:
    dq 0, 0

section .text

extern flush_irqs

%macro push32 1
    sub rsp, 4
    mov dword [rsp], %1
%endmacro

extern gdt

global common_spinup
bits 64
common_spinup:
    cli

    lgdt [rel gdt]
    lidt [rel invalid_idt]

    lea rbx, [rel .reload_cs]

    push 0x28
    push rbx
    retfq
.reload_cs:
    mov eax, 0x30
    mov ds, eax
    mov es, eax
    mov fs, eax
    mov gs, eax
    mov ss, eax

    push r8
    push r9
    push rcx
    push rdx
    call flush_irqs
    pop rdx
    pop rcx
    pop r9
    pop r8

    mov rbp, rsp

    cmp esi, 4
    jle .no_stack_args

.push_stack_args:
    dec esi
    mov eax, [rbp + 8 + rsi*8]
    push32 eax
    test esi, esi
    jnz .push_stack_args

.no_stack_args:
    push32 r9d
    push32 r8d
    push32 ecx
    push32 edx

    lea rbx, [rel .go_32]

    push 0x18
    push rbx
    retfq

bits 32
.go_32:
    mov eax, 0x20
    mov ds, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    mov ss, ax

    xor eax, eax
    lldt ax

    mov eax, 0x00000011
    mov cr0, eax

    mov ecx, 0xc0000080
    xor eax, eax
    xor edx, edx
    wrmsr

    xor eax, eax
    mov cr4, eax

    call edi