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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H11#define _LIBCPP___SUPPORT_IBM_GETTOD_ZOS_H12 13#include <time.h>14 15inline _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), remainder41 DivPair0 = 0;42 register uint64_t DivPair1 asm("r1"); // dividend (lower half), quotient43 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_H53