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 static inline int gettimeofdayMonotonic(struct timespec64* Output) {
16
17 // The POSIX gettimeofday() function is not available on z/OS. Therefore,
18 // we will call stcke and other hardware instructions in implement equivalent.
19 // Note that nanoseconds alone will overflow when reaching new epoch in 2042.
20
21 struct _t {
22 uint64_t Hi;
23 uint64_t Lo;
24 };
25 struct _t Value = {0, 0};
26 uint64_t CC = 0;
27 asm(" stcke %0\n"
28 " ipm %1\n"
29 " srlg %1,%1,28\n"
30 : "=m"(Value), "+r"(CC)::);
31
32 if (CC != 0) {
33 errno = EMVSTODNOTSET;
34 return CC;
35 }
36 uint64_t us = (Value.Hi >> 4);
37 uint64_t ns = ((Value.Hi & 0x0F) << 8) + (Value.Lo >> 56);
38 ns = (ns * 1000) >> 12;
39 us = us - 2208988800000000;
40
41 register uint64_t DivPair0 asm("r0"); // dividend (upper half), remainder
42 DivPair0 = 0;
43 register uint64_t DivPair1 asm("r1"); // dividend (lower half), quotient
44 DivPair1 = us;
45 uint64_t Divisor = 1000000;
46 asm(" dlgr %0,%2" : "+r"(DivPair0), "+r"(DivPair1) : "r"(Divisor) :);
47
48 Output->tv_sec = DivPair1;
49 Output->tv_nsec = DivPair0 * 1000 + ns;
50 return 0;
51 }
52
53 #endif // _LIBCPP_SUPPORT_IBM_GETTOD_ZOS_H
54