global readtsc:function
global readmsr:function
global writemsr:function
global enable_syscall:function
global disable_syscall:function
global setdr0:function
global setdr1:function
global setdr2:function
global setdr3:function
global nextrip:function

setdr0:
	mov rax, dr0
	mov dr0, rdi
	ret

setdr1:
	mov rax, dr1
	mov dr1, rdi
	ret
setdr2:
	mov rax, dr2
	mov dr2, rdi
	ret
setdr3:
	mov rax, dr3
	mov dr3, rdi
	ret

nextrip:
	pop rax
	push rax
	ret
	
readtsc:
	rdtsc
	shl rdx, 32
	or rax, rdx
	ret

writemsr:
	; rdi is msr, rsi is value to write
	mov ecx, edi
	; edx is high order bits, eax is low order bits to write
	mov eax, esi
	shr rsi, 32
	mov edx, esi
	wrmsr
	ret

readmsr:
	mov ecx, edi
	rdmsr
	shl rdx, 32
	or rax, rdx

%define EFER 0xc0000080
enable_syscall:
	mov ecx, EFER
	rdmsr
	or eax, 0x1
	wrmsr
	ret

disable_syscall:
	mov ecx, EFER
	rdmsr
	and eax, DWORD ~0x1
	wrmsr
	ret