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.
//
// Note: Coroutine switches are expected to happen at
// an order of magnitude (or more) higher frequency

	// already running on CPU and there can be lots of them, so a woken up
	// waiter has good chances of losing. In such case it is queued at front
	// of the wait queue. If a waiter fails to acquire the mutex for more than 1ms,
	// it switches mutex to the starvation mode.
	//
	// In starvation mode ownership of the mutex is directly handed off from
	// the unlocking goroutine to the waiter at the front of the queue.

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Tests coroutine switches.

//go:build ignore

package main

import (
	"iter"
	"log"
	"os"
	"runtime/trace"
	"sync"
)

func main() {
	// Start tracing.
	if err := trace.Start(os.Stdout); err != nil {
		log.Fatalf("failed to start tracing: %v", err)
	}

	m.Inter = inter
	m.Type = typ
	// The hash is used in type switches. However, compiler statically generates itab's
	// for all interface/type pairs used in switches (which are added to itabTable
	// in itabsinit). The dynamically-generated itab's never participate in type switches,
	// and thus the hash is irrelevant.
	// Note: m.Hash is _not_ the hash used for the runtime itabTable hash table.

//
// runtime.cgocall (below) calls entersyscall so as not to block
// other goroutines or the garbage collector, and then calls
// runtime.asmcgocall(_cgo_Cfunc_f, frame).
//
// runtime.asmcgocall (in asm_$GOARCH.s) switches to the m->g0 stack
// (assumed to be an operating system-allocated stack, so safe to run
// gcc-compiled code on) and calls _cgo_Cfunc_f(frame).
//
// _cgo_Cfunc_f invokes the actual C function f with arguments

If a developer continuously changes a single file, there is likely no need to rebuild all the other files in the project.

However, what happens when the same developer switches to a new branch created last week?
The files are rebuilt, even though the developer is building something that has been built before.

This is where a *build cache* is helpful.

// systemstack calls fn directly and returns.
// Otherwise, systemstack is being called from the limited stack
// of an ordinary goroutine. In this case, systemstack switches
// to the per-OS-thread stack, calls fn, and switches back.
// It is common to use a func literal as the argument, in order
// to share inputs and outputs with the code around the call
// to system stack:
//
//	... set up y ...

type Extensions struct {
	// x-kubernetes-preserve-unknown-fields stops the API server
	// decoding step from pruning fields which are not specified
	// in the validation schema. This affects fields recursively,
	// but switches back to normal pruning behaviour if nested
	// properties or additionalProperties are specified in the schema.
	// False means that the pruning behaviour is inherited from the parent.
	// False does not mean to activate pruning.

// are no arguments.
TEXT	runtime·racecall(SB), NOSPLIT, $0-0
	MOVD	fn+0(FP), R1
	MOVD	arg0+8(FP), R2
	MOVD	arg1+16(FP), R3
	MOVD	arg2+24(FP), R4
	MOVD	arg3+32(FP), R5
	JMP	racecall<>(SB)

// Switches SP to g0 stack and calls R1. Arguments are already set.
TEXT	racecall<>(SB), NOSPLIT, $0-0
	BL	runtime·save_g(SB)		// Save g for callbacks.
	MOVD	R15, R7				// Save SP.
	MOVD	g_m(g), R8			// R8 = thread.

func panicdottypeE(have, want, iface *byte)
func panicdottypeI(have, want, iface *byte)
func panicnildottype(want *byte)
func typeAssert(s *byte, typ *byte) *byte

// interface switches
func interfaceSwitch(s *byte, t *byte) (int, *byte)

// interface equality. Type/itab pointers are already known to be equal, so
// we only need to pass one.
func ifaceeq(tab *uintptr, x, y unsafe.Pointer) (ret bool)