shithub: mc

ref: 79c93065bf8467896e078459a91e36dc66ddaaeb
dir: /lib/thread/spawn+freebsd.myr/

use sys
use std

pkg thread =
	type tid = uint64

	const spawn : (fn : (-> void) -> std.result(tid, byte[:]))
;;


const Stacksz = 8*std.MiB
extern const exit : (-> void)

const spawn = {fn
	-> spawnstk(fn, Stacksz)
}

const spawnstk = {fn, sz
	var stk : byte#, tid, ctid, ret
	var szp, fp, tos

	stk = getstk(sz)
	if stk == sys.Mapbad
		-> `std.Fail "couldn't get stack"
	;;
	tid = -1
	/* find top of stack */
	tos = (stk castto(std.intptr)) + (sz castto(std.intptr))

	/* store the stack size */
	tos -= sizeof(sys.size)
	sz -= sizeof(sys.size)
	szp = tos castto(sys.size#)
	szp# = Stacksz

	/* store the function we call */
	tos -= sizeof((->void))
	sz -= sizeof((->void))
	fp = tos castto((->void)#)
	fp# = fn

	ret = sys.thr_new(&[
		.startfn = startthread castto(void#),
		.arg = tos castto(void#),
		.stkbase = stk castto(byte#),
		.stksz = sz,
		.tid = &ctid,
		.ptid = &tid,
		.flags = 2,
		.rtp = 0 castto(sys.rtprio#)
	], sizeof(sys.thrparam))

	if ret < 0
		-> `std.Fail "couldn't spawn thread"
	;;
	-> `std.Ok tid castto(tid)
}

const getstk = {sz
	var p, m

	p = sys.mmap(0 castto(byte#), sz, sys.Mprotrw, sys.Mpriv | sys.Manon, -1, 0)
	if p == sys.Mapbad
		-> p
	;;
	m = p castto(std.intptr)
	-> m castto(byte#)
}

const startthread = {fn : (-> void)#
	fn#()
	exit()
}