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
gettimeofdayMonotonic(struct timespec64 * Output)15 inline _LIBCPP_HIDE_FROM_ABI int gettimeofdayMonotonic(struct timespec64* Output) {
16 // The POSIX gettimeofday() function is not available on z/OS. Therefore,
17 // we will call stcke and other hardware instructions in implement equivalent.
18 // Note that nanoseconds alone will overflow when reaching new epoch in 2042.
19
20 struct _t {
21 uint64_t Hi;
22 uint64_t Lo;
23 };
24 struct _t Value = {0, 0};
25 uint64_t CC = 0;
26 asm(" stcke %0\n"
27 " ipm %1\n"
28 " srlg %1,%1,28\n"
29 : "=m"(Value), "+r"(CC)::);
30
31 if (CC != 0) {
32 errno = EMVSTODNOTSET;
33 return CC;
34 }
35 uint64_t us = (Value.Hi >> 4);
36 uint64_t ns = ((Value.Hi & 0x0F) << 8) + (Value.Lo >> 56);
37 ns = (ns * 1000) >> 12;
38 us = us - 2208988800000000;
39
40 register uint64_t DivPair0 asm("r0"); // dividend (upper half), remainder
41 DivPair0 = 0;
42 register uint64_t DivPair1 asm("r1"); // dividend (lower half), quotient
43 DivPair1 = us;
44 uint64_t Divisor = 1000000;
45 asm(" dlgr %0,%2" : "+r"(DivPair0), "+r"(DivPair1) : "r"(Divisor) :);
46
47 Output->tv_sec = DivPair1;
48 Output->tv_nsec = DivPair0 * 1000 + ns;
49 return 0;
50 }
51
52 #endif // _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H
53