1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
3 //
4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5 // See https://llvm.org/LICENSE.txt for license information.
6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //
8 //===----------------------------------------------------------------------===//
9
10 #ifndef _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H
11 #define _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H
12
13 #include <time.h>
14
15 inline _LIBCPP_HIDE_FROM_ABI int
gettimeofdayMonotonic(struct timespec64 * Output)16 gettimeofdayMonotonic(struct timespec64* Output) {
17
18 // The POSIX gettimeofday() function is not available on z/OS. Therefore,
19 // we will call stcke and other hardware instructions in implement equivalent.
20 // Note that nanoseconds alone will overflow when reaching new epoch in 2042.
21
22 struct _t {
23 uint64_t Hi;
24 uint64_t Lo;
25 };
26 struct _t Value = {0, 0};
27 uint64_t CC = 0;
28 asm(" stcke %0\n"
29 " ipm %1\n"
30 " srlg %1,%1,28\n"
31 : "=m"(Value), "+r"(CC)::);
32
33 if (CC != 0) {
34 errno = EMVSTODNOTSET;
35 return CC;
36 }
37 uint64_t us = (Value.Hi >> 4);
38 uint64_t ns = ((Value.Hi & 0x0F) << 8) + (Value.Lo >> 56);
39 ns = (ns * 1000) >> 12;
40 us = us - 2208988800000000;
41
42 register uint64_t DivPair0 asm("r0"); // dividend (upper half), remainder
43 DivPair0 = 0;
44 register uint64_t DivPair1 asm("r1"); // dividend (lower half), quotient
45 DivPair1 = us;
46 uint64_t Divisor = 1000000;
47 asm(" dlgr %0,%2" : "+r"(DivPair0), "+r"(DivPair1) : "r"(Divisor) :);
48
49 Output->tv_sec = DivPair1;
50 Output->tv_nsec = DivPair0 * 1000 + ns;
51 return 0;
52 }
53
54 #endif // _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H
55