JMP	asancall<>(SB)

// Switches SP to g0 stack and calls (FARG). Arguments already set.
TEXT	asancall<>(SB), NOSPLIT, $0-0
	MOVD	RSP, R19                  // callee-saved
	CBZ	g, g0stack                // no g, still on a system stack
	MOVD	g_m(g), R10
	MOVD	m_g0(R10), R11
	CMP	R11, g
	BEQ	g0stack

	MOVD	(g_sched+gobuf_sp)(R11), R5
	MOVD	R5, RSP

g0stack:
	BL	(FARG)
	MOVD	R19, RSP

	JMP	asancall<>(SB)

// Switches SP to g0 stack and calls (FARG). Arguments already set.
TEXT	asancall<>(SB), NOSPLIT, $0-0
	MOVV	R3, R23         // callee-saved
	BEQ	g, g0stack      // no g, still on a system stack
	MOVV	g_m(g), R14
	MOVV	m_g0(R14), R15
	BEQ	R15, g, g0stack

	MOVV	(g_sched+gobuf_sp)(R15), R9
	MOVV	R9, R3

g0stack:
	JAL	(FARG)
	MOVV	R23, R3

	//
	// An event may not be both a timed event and have data.
	HasData bool

	// IsStack indicates that the event represents a complete
	// stack trace. Specifically, it means that after the arguments
	// there's a varint length, followed by 4*length varints. Each
	// group of 4 represents the PC, file ID, func ID, and line number
	// in that order.
	IsStack bool

	// Experiment indicates the ID of an experiment this event is associated

	MOVW	g, m_g0(R8)
	// save g->m = m0
	MOVW	R8, g_m(g)

	// create istack out of the OS stack
	// (1MB of system stack is available on iOS and Android)
	MOVW	$(-64*1024+104)(R13), R0
	MOVW	R0, g_stackguard0(g)
	MOVW	R0, g_stackguard1(g)
	MOVW	R0, (g_stack+stack_lo)(g)
	MOVW	R13, (g_stack+stack_hi)(g)

	BL	runtime·emptyfunc(SB)	// fault if stack check is wrong

#ifdef GOOS_openbsd

	MOV	$__asan_register_globals_go(SB), X14
	JMP	asancall<>(SB)

// Switches SP to g0 stack and calls (X14). Arguments already set.
TEXT	asancall<>(SB), NOSPLIT, $0-0
	MOV	X2, X8		// callee-saved
	BEQZ	g, g0stack	// no g, still on a system stack
	MOV	g_m(g), X21
	MOV	m_g0(X21), X21
	BEQ	X21, g, g0stack

	MOV	(g_sched+gobuf_sp)(X21), X2

g0stack:
	JALR	RA, X14
	MOV	X8, X2

	JMP	msancall<>(SB)

// Switches SP to g0 stack and calls (FARG). Arguments already set.
TEXT	msancall<>(SB), NOSPLIT, $0-0
	MOVV	R3, R23         // callee-saved
	BEQ	g, g0stack      // no g, still on a system stack
	MOVV	g_m(g), R14
	MOVV	m_g0(R14), R15
	BEQ	R15, g, g0stack

	MOVV	(g_sched+gobuf_sp)(R15), R9
	MOVV	R9, R3

g0stack:
	JAL	(FARG)
	MOVV	R23, R3

	JMP	msancall<>(SB)

// Switches SP to g0 stack and calls (FARG). Arguments already set.
TEXT	msancall<>(SB), NOSPLIT, $0-0
	MOVD	RSP, R19                  // callee-saved
	CBZ	g, g0stack                // no g, still on a system stack
	MOVD	g_m(g), R10
	MOVD	m_g0(R10), R11
	CMP	R11, g
	BEQ	g0stack

	MOVD	(g_sched+gobuf_sp)(R11), R4
	MOVD	R4, RSP

g0stack:
	BL	(FARG)
	MOVD	R19, RSP

	MOVL	AX, ret+8(FP)
	RET

TEXT runtime·tstart_plan9(SB),NOSPLIT,$8
	MOVQ	newm+0(FP), CX
	MOVQ	m_g0(CX), DX

	// Layout new m scheduler stack on os stack.
	MOVQ	SP, AX
	MOVQ	AX, (g_stack+stack_hi)(DX)
	SUBQ	$(64*1024), AX		// stack size
	MOVQ	AX, (g_stack+stack_lo)(DX)
	MOVQ	AX, g_stackguard0(DX)
	MOVQ	AX, g_stackguard1(DX)

	// Initialize procid from TOS struct.
	MOVQ	_tos(SB), AX
	MOVL	64(AX), AX

	MOVD	m_g0(R0), g
	MOVD	R0, g_m(g)
	BL	runtime·save_g(SB)

	// Set up stack guards for OS stack.
	MOVD	RSP, R0
	MOVD	R0, g_stack+stack_hi(g)
	SUB	$(64*1024), R0
	MOVD	R0, (g_stack+stack_lo)(g)
	MOVD	R0, g_stackguard0(g)
	MOVD	R0, g_stackguard1(g)

	BL	runtime·emptyfunc(SB)	// fault if stack check is wrong
	BL	runtime·mstart(SB)

	RESTORE_R19_TO_R28(8*3)

	// Exit the thread.

	XOR	 R0, R0 // reset R0

	// set g
	MOVD	m_g0(R3), g
	BL	runtime·save_g(SB)
	MOVD	R3, g_m(g)

	// Layout new m scheduler stack on os stack.
	MOVD	R1, R3
	MOVD	R3, (g_stack+stack_hi)(g)
	SUB	$(const_threadStackSize), R3		// stack size
	MOVD	R3, (g_stack+stack_lo)(g)
	ADD	$const_stackGuard, R3
	MOVD	R3, g_stackguard0(g)
	MOVD	R3, g_stackguard1(g)

	BL	runtime·mstart(SB)

	MOVD R0, R3