MOVWZ (R3+R5), R4		<=>	lwzx r4,r3,r5
	MOVHZ  (R3), R4		<=>	lhz r4,0(r3)
	MOVHU 2(R3), R4		<=>	lhau r4,2(r3)
	MOVBZ (R3), R4		<=>	lbz r4,0(r3)

	MOVD R4,(R3)		<=>	std r4,0(r3)
	MOVW R4,(R3)		<=>	stw r4,0(r3)
	MOVW R4,(R3+R5)		<=>	stwx r4,r3,r5
	MOVWU R4,4(R3)		<=>	stwu r4,4(r3)
	MOVH R4,2(R3)		<=>	sth r4,2(r3)
	MOVBU R4,(R3)(R5)		<=>	stbux r4,r3,r5

4. Compares

}

const (
	// Block reasons
	sForever = iota
	sPreempted
	sGosched
	sSleep
	sChanSend
	sChanRecv
	sNetwork
	sSync
	sSyncCond
	sSelect
	sEmpty
	sMarkAssistWait

	// STW kinds
	sSTWUnknown
	sSTWGCMarkTermination
	sSTWGCSweepTermination
	sSTWWriteHeapDump
	sSTWGoroutineProfile
	sSTWGoroutineProfileCleanup
	sSTWAllGoroutinesStackTrace
	sSTWReadMemStats
	sSTWAllThreadsSyscall

//
// If flags&gcDrainFlushBgCredit != 0, gcDrain flushes scan work
// credit to gcController.bgScanCredit every gcCreditSlack units of
// scan work.
//
// gcDrain will always return if there is a pending STW or forEachP.
//
// Disabling write barriers is necessary to ensure that after we've
// confirmed that we've drained gcw, that we don't accidentally end
// up flipping that condition by immediately adding work in the form

// compute populates the cpuStatsAggregate with values from the runtime.
func (a *cpuStatsAggregate) compute() {
	a.cpuStats = work.cpuStats
	// TODO(mknyszek): Update the CPU stats again so that we're not
	// just relying on the STW snapshot. The issue here is that currently
	// this will cause non-monotonicity in the "user" CPU time metric.
	//
	// a.cpuStats.accumulate(nanotime(), gcphase == _GCmark)
}

	// allspans is a slice of all mspans ever created. Each mspan
	// appears exactly once.
	//
	// The memory for allspans is manually managed and can be
	// reallocated and move as the heap grows.
	//
	// In general, allspans is protected by mheap_.lock, which
	// prevents concurrent access as well as freeing the backing
	// store. Accesses during STW might not hold the lock, but

			}
			evGC = nil
		case EvSTWStart:
			evp := &evSTW
			if *evp != nil {
				return fmt.Errorf("previous STW is not ended before a new one (time %d)", ev.Ts)
			}
			*evp = ev
		case EvSTWDone:
			evp := &evSTW
			if *evp == nil {
				return fmt.Errorf("bogus STW end (time %d)", ev.Ts)
			}
			*evp = nil
		case EvGCSweepStart:
			p := ps[ev.P]
			if p.evSweep != nil {

	bgScanCredit atomic.Int64

	// assistTime is the nanoseconds spent in mutator assists
	// during this cycle. This is updated atomically, and must also
	// be updated atomically even during a STW, because it is read
	// by sysmon. Updates occur in bounded batches, since it is both
	// written and read throughout the cycle.
	assistTime atomic.Int64

		panic("Range called on non-Range event")
	}
	var r Range
	switch e.base.typ {
	case go122.EvSTWBegin, go122.EvSTWEnd:
		// N.B. ordering.advance smuggles in the STW reason as e.base.args[0]
		// for go122.EvSTWEnd (it's already there for Begin).
		r.Name = "stop-the-world (" + e.table.strings.mustGet(stringID(e.base.args[0])) + ")"

			// CMP Rarg0, $0
			// BNE 2(PC)
			// STW R0, 0(R0)
			// NOP (so the BNE has somewhere to land)

			// CMP Rarg0, $0
			p := s.Prog(ppc64.ACMP)
			p.From.Type = obj.TYPE_REG
			p.From.Reg = v.Args[0].Reg()
			p.To.Type = obj.TYPE_CONST
			p.To.Offset = 0

			// BNE 2(PC)
			p2 := s.Prog(ppc64.ABNE)
			p2.To.Type = obj.TYPE_BRANCH

			// STW R0, 0(R0)

		n:    uintptr(n),
		args: args,
	}
	asmstdcall_trampoline(noescape(unsafe.Pointer(&libcall)))
	return libcall.r1
}

// Calling stdcall on os stack.
// May run during STW, so write barriers are not allowed.
//
//go:nowritebarrier
//go:nosplit
func stdcall(fn stdFunction) uintptr {
	gp := getg()
	mp := gp.m
	mp.libcall.fn = uintptr(unsafe.Pointer(fn))
	resetLibcall := false