ref: 15ad5bac3dd1a18be6e632afa73f5ac12b4a5ec1
dir: /lib/thread/futex+linux.myr/
use std use sys use "atomic" use "common" pkg thread = type ftxtag = uint32 impl atomic ftxtag const ftxwait : (uaddr : ftxtag#, val : ftxtag, tmout : std.time -> sys.errno) const ftxwake : (uaddr : ftxtag# -> void) const ftxwakeall : (uaddr : ftxtag# -> void) ;; const ftxwait = {uaddr, val, tmout var rc if tmout < 0 while (rc = (sys.futex((uaddr : int32#), sys.Futexwait | sys.Futexpriv, (val : int32), Zptr, Zptr, 0) : sys.errno)) == sys.Eintr ;; else var t = (tmout : int64) var ts std.assert(sys.clock_gettime(`sys.Clockmonotonic, &ts) == 0, "error: clock_gettime returned -1\n") ts.nsec += (t % 1_000_000) * 1000 ts.sec += (ts.nsec / 1_000_000_000) + (t / 1_000_000) ts.nsec %= 1_000_000_000 /* Futexwaitbitset + Futexbitsetmatchany causes the timeout to be treated as absolute rather than relative. */ while (rc = (sys.futex((uaddr : int32#), sys.Futexwaitbitset | sys.Futexpriv, (val : int32), &ts, Zptr, sys.Futexbitsetmatchany) : sys.errno)) == sys.Eintr ;; ;; match rc | 0: -> 0 | sys.Eagain: -> sys.Eagain | sys.Etimedout: -> sys.Etimedout | err: std.fput(2, "error: futex returned {}\n", err) std.suicide() ;; } const ftxwake = {uaddr sys.futex((uaddr : int32#), sys.Futexwake | sys.Futexpriv, 1, Zptr, Zptr, 0) } const ftxwakeall = {uaddr sys.futex((uaddr : int32#), sys.Futexwake | sys.Futexpriv, 0x7fffffff, Zptr, Zptr, 0) } impl atomic ftxtag = xget = {p; -> (xget32((p : uint32#)) : ftxtag)} xset = {p, v; xset32((p : uint32#), (v : uint32))} xadd = {p, v; -> (xadd32((p : uint32#), (v : uint32)) : ftxtag)} xcas = {p, old, new; -> (xcas32((p : uint32#), (old : uint32), (new : uint32)) : ftxtag)} xchg = {p, v; -> (xchg32((p : uint32#), (v : uint32)) : ftxtag)} ;;