magenta/arch/x86_64/acpi/ap_trampoline.S

	.global acpi_bsp_lapic_id
	.type acpi_bsp_lapic_id, @function

acpi_bsp_lapic_id:
	push %rbp
	mov %rsp, %rbp

	push %rbx

	mov $0x00000001, %eax
	cpuid
	shrq $0x18, %rbx

	mov %rbx, %rax

	pop %rbx
	pop %rbp
	ret


	.extern __ap_stack_top
	.extern __bsp_done

	.extern ap_startup
	.type ap_startup, @function

	.global ap_trampoline_code

	# this code will be relocated to 0x8000, sets up environment for calling a C function
	.code16
ap_trampoline_code:
	cli
	cld
	ljmp    $0, $0x8040
	.align 16
_L8010_GDT_table:
	.long 0, 0
	.long 0x0000FFFF, 0x00CF9A00    # flat code
	.long 0x0000FFFF, 0x008F9200    # flat data
	.long 0x00000068, 0x00CF8900    # tss
_L8030_GDT_value:
	.word _L8030_GDT_value - _L8010_GDT_table - 1
	.long 0x8010
	.long 0, 0
	.align 64
_L8040:
	xorw    %ax, %ax
	movw    %ax, %ds
	lgdtl   0x8030
	movl    %cr0, %eax
	orl     $1, %eax
	movl    %eax, %cr0
	ljmp    $8, $0x8060

	.align 32
	.code32
_L8060:
	movw    $16, %ax
	movw    %ax, %ds
	movw    %ax, %ss
	# get our Local APIC ID
	mov     $1, %eax
	cpuid
	shrl    $24, %ebx
	movl    %ebx, %edi

	movl    $0x9000, %eax
	movl    (%eax), %eax
	mov     %eax, %cr3
	hlt
	# set up 32k stack, one for each core. It is important that all core must have its own stack
	#shll    $15, %ebx
	#movl    __ap_stack_top, %esp
	#subl    %ebx, %esp
	#pushl   %edi
	# spinlock, wait for the BSP to finish
#1:  	pause
	#cmpb    $0, __bsp_done
	#jz      1b
	#lock    incb aprunning
	# jump into C code (should never return)
	#ljmp    $8, $ap_startup