const (
	debugCallSystemStack = "executing on Go runtime stack"
	debugCallUnknownFunc = "call from unknown function"
	debugCallRuntime     = "call from within the Go runtime"
	debugCallUnsafePoint = "call not at safe point"
)

func debugCallV2()
func debugCallPanicked(val any)

// debugCallCheck checks whether it is safe to inject a debugger
// function call with return PC pc. If not, it returns a string
// explaining why.
//
//go:nosplit

func getg() *g

// mcall switches from the g to the g0 stack and invokes fn(g),
// where g is the goroutine that made the call.
// mcall saves g's current PC/SP in g->sched so that it can be restored later.
// It is up to fn to arrange for that later execution, typically by recording
// g in a data structure, causing something to call ready(g) later.

func coroexit(c *coro) {
	gp := getg()
	gp.coroarg = c
	gp.coroexit = true
	mcall(coroswitch_m)
}

//go:linkname coroswitch

// coroswitch switches to the goroutine blocked on c
// and then blocks the current goroutine on c.
func coroswitch(c *coro) {
	gp := getg()
	gp.coroarg = c
	mcall(coroswitch_m)
}

// coroswitch_m is the implementation of coroswitch
// that runs on the m stack.
//

)

// The actual CPU hogging function.
// Must not call other functions nor access heap/globals in the loop,
// otherwise under race detector the samples will be in the race runtime.
func cpuHog1(x int) int {
	return cpuHog0(x, 1e5)
}

func cpuHog0(x, n int) int {
	foo := x
	for i := 0; i < n; i++ {
		if i%1000 == 0 {
			// Spend time in mcall, stored as gp.m.curg, with g0 running
			runtime.Gosched()
		}

//go:nosplit
func asyncPreempt2() {
	gp := getg()
	gp.asyncSafePoint = true
	if gp.preemptStop {
		mcall(preemptPark)
	} else {
		mcall(gopreempt_m)
	}
	gp.asyncSafePoint = false
}

// asyncPreemptStack is the bytes of stack space required to inject an
// asyncPreempt call.
var asyncPreemptStack = ^uintptr(0)

func init() {
	f := findfunc(abi.FuncPCABI0(asyncPreempt))

		pcBuf[0] = uintptr(skip)
		if getg() == gp {
			nstk += fpTracebackPCs(unsafe.Pointer(getfp()), pcBuf[1:])
		} else if gp != nil {
			// Three cases:
			//
			// (1) We're called on the g0 stack through mcall(fn) or systemstack(fn). To
			// behave like gcallers above, we start unwinding from sched.bp, which
			// points to the caller frame of the leaf frame on g's stack. The return

	MOVQ	SP, R12		// callee-saved, preserved across the CALL
	MOVQ	m_g0(R13), R10
	CMPQ	R10, R14
	JE	call	// already on g0
	MOVQ	(g_sched+gobuf_sp)(R10), SP
call:
	ANDQ	$~15, SP	// alignment for gcc ABI
	CALL	AX
	MOVQ	R12, SP
	// Back to Go world, set special registers.
	// The g register (R14) is preserved in C.
	XORPS	X15, X15
	RET

// C->Go callback thunk that allows to call runtime·racesymbolize from C code.

	MOVD	16(R1), R10		// LR was saved away, restore for return
	MOVD	R10, LR
	RET

// C->Go callback thunk that allows to call runtime·racesymbolize from C code.
// Direct Go->C race call has only switched SP, finish g->g0 switch by setting correct g.
// The overall effect of Go->C->Go call chain is similar to that of mcall.
// RARG0 contains command code. RARG1 contains command-specific context.
// See racecallback for command codes.

	SUB	$16, RSP
	BL	R9
	MOVD	R19, RSP
	JMP	(R20)

// C->Go callback thunk that allows to call runtime·racesymbolize from C code.
// Direct Go->C race call has only switched SP, finish g->g0 switch by setting correct g.
// The overall effect of Go->C->Go call chain is similar to that of mcall.
// R0 contains command code. R1 contains command-specific context.
// See racecallback for command codes.

// so that we can set up g0.sched to return to the call of mstart1 above.
//
//go:noinline
func mstart1() {
	gp := getg()

	if gp != gp.m.g0 {
		throw("bad runtime·mstart")
	}

	// Set up m.g0.sched as a label returning to just
	// after the mstart1 call in mstart0 above, for use by goexit0 and mcall.
	// We're never coming back to mstart1 after we call schedule,