MOVD	R0, R19
	BL	libc_mach_absolute_time(SB)
	MOVD	R0, 0(R19)
	MOVW	timebase<>+machTimebaseInfo_numer(SB), R20
	MOVD	$timebase<>+machTimebaseInfo_denom(SB), R21
	LDARW	(R21), R21	// atomic read
	CMP	$0, R21
	BNE	initialized

	SUB	$(machTimebaseInfo__size+15)/16*16, RSP
	MOVD	RSP, R0
	BL	libc_mach_timebase_info(SB)
	MOVW	machTimebaseInfo_numer(RSP), R20
	MOVW	machTimebaseInfo_denom(RSP), R21

	MOVQ	DI, BX
	CALL	libc_mach_absolute_time(SB)
	MOVQ	AX, 0(BX)
	MOVL	timebase<>+machTimebaseInfo_numer(SB), SI
	MOVL	timebase<>+machTimebaseInfo_denom(SB), DI // atomic read
	TESTL	DI, DI
	JNE	initialized

	SUBQ	$(machTimebaseInfo__size+15)/16*16, SP
	MOVQ	SP, DI
	CALL	libc_mach_timebase_info(SB)
	MOVL	machTimebaseInfo_numer(SP), SI
	MOVL	machTimebaseInfo_denom(SP), DI
	ADDQ	$(machTimebaseInfo__size+15)/16*16, SP