Add precise_time.c to misc to help speed up Windows

https://github.com/Hamlib/Hamlib/issues/1290

lib/Makefile.am

@@ -1,7 +1,7 @@
-EXTRA_DIST = getopt.c getopt.h getopt_long.c usleep.c \
+EXTRA_DIST = getopt.c getopt.h getopt_long.c usleep.c \ 
 	termios.c win32termios.h gettimeofday.c getaddrinfo.c
 
 noinst_LTLIBRARIES = libmisc.la
 
-libmisc_la_SOURCES = cJSON.c cJSON.h asyncpipe.c asyncpipe.h
+libmisc_la_SOURCES = cJSON.c cJSON.h asyncpipe.c asyncpipe.h precise_time.c
 libmisc_la_LIBADD = $(LTLIBOBJS) $(NET_LIBS)

lib/precise_time.c

@@ -0,0 +1,164 @@
+// ---------------------------------------------------------------------
+// precise_time.cxx
+//
+// Copyright (C) 2023
+//		Dave Freese, W1HKJ
+//
+// This file is part of flrig
+//
+// flrig is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// flrig is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with fldigi.  If not, see <http://www.gnu.org/licenses/>.
+// ---------------------------------------------------------------------
+
+#include <errno.h>
+#include <time.h>
+#include <sys/time.h>
+
+#if 0
+// return current tick time in seconds
+double monotonic_seconds()
+{
+	static struct timeval t1;
+	gettimeofday(&t1, NULL);
+	return t1.tv_sec + t1.tv_usec / 1e6;
+}
+
+#else
+
+//======================================================================
+//
+// A cross platform monotonic timer.
+// Copyright 2013 Alex Reece.
+//
+
+#include <unistd.h>
+
+#define NANOS_PER_SECF 1000000000.0
+#define USECS_PER_SEC 1000000
+
+static int showme = 0;
+
+#if _POSIX_TIMERS > 0 && defined(_POSIX_MONOTONIC_CLOCK)
+	// If we have it, use clock_gettime and CLOCK_MONOTONIC.
+
+	#include <time.h>
+
+	double monotonic_seconds() {
+		if (showme) {
+			showme = 0;
+		}
+		struct timespec time;
+		// Note: Make sure to link with -lrt to define clock_gettime.
+		clock_gettime(CLOCK_MONOTONIC, &time);
+		return ((double) time.tv_sec) + ((double) time.tv_nsec / (NANOS_PER_SECF));
+	}
+
+#elif defined(__APPLE__)
+	// If we don't have CLOCK_MONOTONIC, we might be on a Mac. There we instead
+	// use mach_absolute_time().
+
+	#include <mach/mach_time.h>
+
+	static mach_timebase_info_data_t info;
+	static void __attribute__((constructor)) init_info() {
+		mach_timebase_info(&info);
+	}
+
+	double monotonic_seconds() {
+		uint64_t time = mach_absolute_time();
+		double dtime = (double) time;
+		dtime *= (double) info.numer;
+		dtime /= (double) info.denom;
+		return dtime / NANOS_PER_SECF;
+	}
+
+#elif defined(__WIN32__)
+	// On Windows, use QueryPerformanceCounter and QueryPerformanceFrequency.
+
+	#include <windows.h>
+
+	static double PCFreq = 0.0;
+
+	// According to http://stackoverflow.com/q/1113409/447288, this will
+	// make this function a constructor.
+	// TODO(awreece) Actually attempt to compile on windows.
+	// w1hkj - builds OK on mingw32
+
+	static void __cdecl init_pcfreq();
+	__declspec(allocate(".CRT$XCU")) void (__cdecl*init_pcfreq_)() = init_pcfreq;
+	static void __cdecl init_pcfreq() {
+		// Accoring to http://stackoverflow.com/a/1739265/447288, this will
+		// properly initialize the QueryPerformanceCounter.
+		LARGE_INTEGER li;
+		int has_qpc = QueryPerformanceFrequency(&li);
+		assert(has_qpc);
+
+		PCFreq = ((double) li.QuadPart) / 1000.0;
+	}
+
+	double monotonic_seconds() {
+		LARGE_INTEGER li;
+		QueryPerformanceCounter(&li);
+		return ((double) li.QuadPart) / PCFreq;
+	}
+
+#else
+	// Fall back to rdtsc. The reason we don't use clock() is this scary message
+	// from the man page:
+	//     "On several other implementations, the value returned by clock() also
+	//      includes the times of any children whose status has been collected via
+	//      wait(2) (or another wait-type call)."
+	//
+	// Also, clock() only has microsecond accuracy.
+	//
+	// This whitepaper offered excellent advice on how to use rdtscp for
+	// profiling: http://download.intel.com/embedded/software/IA/324264.pdf
+	//
+	// Unfortunately, we can't follow its advice exactly with our semantics,
+	// so we're just going to use rdtscp with cpuid.
+	//
+	// Note that rdtscp will only be available on new processors.
+
+	#include <stdint.h>
+
+	static inline uint64_t rdtsc() {
+		uint32_t hi, lo;
+		asm volatile("rdtscp\n"
+								 "movl %%edx, %0\n"
+								 "movl %%eax, %1\n"
+								 "cpuid"
+								 : "=r" (hi), "=r" (lo) : : "%rax", "%rbx", "%rcx", "%rdx");
+		return (((uint64_t)hi) << 32) | (uint64_t)lo;
+	}
+
+	static uint64_t rdtsc_per_sec = 0;
+	static void __attribute__((constructor)) init_rdtsc_per_sec() {
+		uint64_t before, after;
+
+		before = rdtsc();
+		usleep(USECS_PER_SEC);
+		after = rdtsc();
+
+		rdtsc_per_sec = after - before;
+	}
+
+	double monotonic_seconds() {
+		if (showme) {
+			showme = false;
+		}
+		return (double) rdtsc() / (double) rdtsc_per_sec;
+	}
+
+#endif
+
+#endif