[exec:patch] exec patch -p1 -i diff.patch
[exec:patch] go mod tidy -diff
[exec:patch] cmp go.mod go.mod.tidyResult
[exec:patch] cmp go.sum go.sum.tidyResult

go list -m all
cmp stdout m_all.txt

go mod edit -go=1.16
go list -m all
cmp stdout m_all.txt


# If we explicitly drop compatibility with 1.16, we retain fewer checksums,
# which gives a cleaner go.sum file but causes 1.16 to fail in readonly mode.

cp go.mod.orig go.mod

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.
//

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()
		}
		if foo > 0 {
			foo *= foo
		} else {
			foo *= foo + 1
		}
	}
	return foo