Moved the uPause function to timmings.h for modularity and easier porting to BSD.

2001-12-23 19:43:20 +00:00
parent 54eb272a69
commit 5de08960bf
6 changed files with 141 additions and 223 deletions
@@ -0,0 +1,110 @@
+#ifndef _TIMING_H
+#define _TIMING_H
+
+/*
+ * Utility header file for timing functions
+ *
+ * Made by Guillaume Filion, moved from the HD44780 driver.
+ *
+ * From hd44780.c:
+ * Modified July 2000 by Charles Steinkuehler to use one of 3 methods for delay
+ * timing.  I/O reads, gettimeofday, and nanosleep.  Of the three, nanosleep
+ * seems to work best, so that's what is set by default.
+ *
+ * This file is released under the GNU General Public License. Refer to the
+ * COPYING file distributed with this package.
+ *
+ * Copyright (c)  2001 Guillaume Filion <gfk@logidac.com>
+ *                2000 Charles Steinkuehler <cstein@newtek.com>
+ */
+
+// Uncomment one of the lines below to select your desired delay generation
+// mechanism.  If both defines are commented, the original I/O read timing
+// loop is used.  Using DELAY_NANOSLEEP  seems to provide the best performance.
+//#define DELAY_GETTIMEOFDAY
+#ifdef HAVE_SCHED_H
+# define DELAY_NANOSLEEP
+#else
+# define DELAY_GETTIMEOFDAY
+#endif
+
+#if TIME_WITH_SYS_TIME
+# include <sys/time.h>
+# include <time.h>
+#else
+# if HAVE_SYS_TIME_H
+#  include <sys/time.h>
+# else
+#  include <time.h>
+# endif
+#endif
+
+// Only one alternate delay method at a time, please ;-)
+#if defined DELAY_GETTIMEOFDAY
+# undef DELAY_NANOSLEEP
+#elif defined DELAY_NANOSLEEP
+# include <sched.h>
+# include <time.h>
+#endif
+
+static int delayMult = 0;	 // Delay multiplier for slow displays
+
+/////////////////////////////////////////////////////////////////
+// Initialisation
+//
+static inline int timing_init() {
+#if defined DELAY_NANOSLEEP
+	// Change to Round-Robin scheduling for nanosleep
+	{
+		// Set priority to 1
+		struct sched_param param;
+		param.sched_priority=1;
+		if (( sched_setscheduler(0, SCHED_RR, &param)) == -1) {
+			fprintf (stderr, "timing_init: failed (%s)\n", strerror (errno));
+			return -1;
+		}
+	}
+#endif
+	return 0;
+}
+
+/////////////////////////////////////////////////////////////////
+// IO delay to avoid a task switch
+//
+static inline void timing_uPause (int usecs) {
+	int delay = usecs * delayMult;  // To correct for slower displays
+
+#if defined DELAY_GETTIMEOFDAY
+	struct timeval current_time,delay_time,wait_time;
+
+	// Get current time first thing
+	gettimeofday(&current_time,NULL);
+
+	// Calculate when delay is over
+	delay_time.tv_sec  = 0;
+	delay_time.tv_usec = delay;
+	timeradd(&current_time,&delay_time,&wait_time);
+
+	do {
+		gettimeofday(&current_time,NULL);
+	} while (timercmp(&current_time,&wait_time,<));
+
+#elif defined DELAY_NANOSLEEP
+	struct timespec delay_time,remaining;
+
+	delay_time.tv_sec = 0;
+	delay_time.tv_nsec = delay * 1000;
+	while ( nanosleep(&delay_time,&remaining) == -1 )
+	{
+		delay_time.tv_sec  = remaining.tv_sec;
+		delay_time.tv_nsec = remaining.tv_nsec;
+	}
+#else // using I/O timing
+      // Assuming every port I/O takes 1ms, we'll do at least one.
+	int i=0;
+	do { port_in (port); } while (i++ < delay/1000);
+#endif
+}
+
+
+#endif // _TIMING_H