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___CXX03___SUPPORT_IBM_GETTOD_ZOS_H 11 #define _LIBCPP___CXX03___SUPPORT_IBM_GETTOD_ZOS_H 12 13 #include <__cxx03/time.h> 14 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___CXX03___SUPPORT_IBM_GETTOD_ZOS_H 53