From 41be2e8943d8737c0074c266aa9c463ab7faff05 Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Tue, 17 Sep 1996 21:31:30 +0000
Subject: added routine _POSIX_Timespec_subtract

---
 cpukit/posix/src/time.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

(limited to 'cpukit/posix')

diff --git a/cpukit/posix/src/time.c b/cpukit/posix/src/time.c
index 125db4d16b..f184f200e8 100644
--- a/cpukit/posix/src/time.c
+++ b/cpukit/posix/src/time.c
@@ -14,6 +14,37 @@
 #include <rtems/posix/seterr.h>
 #include <rtems/posix/time.h>
 
+/*PAGE
+ *
+ *  _POSIX_Timespec_subtract
+ */
+
+void _POSIX_Timespec_subtract(
+  const struct timespec *the_start,
+  const struct timespec *end,
+  struct timespec *result
+)
+{
+  struct timespec  start_struct = *the_start;
+  struct timespec *start = &start_struct;
+  unsigned int nsecs_per_sec = TOD_NANOSECONDS_PER_SECOND;
+ 
+  if (end->tv_nsec < start->tv_nsec) {
+    int seconds = (start->tv_nsec - end->tv_nsec) / nsecs_per_sec + 1;
+    start->tv_nsec -= nsecs_per_sec * seconds;
+    start->tv_sec += seconds;
+  }
+ 
+  if (end->tv_nsec - start->tv_nsec > nsecs_per_sec) {
+    int seconds = (start->tv_nsec - end->tv_nsec) / nsecs_per_sec;
+    start->tv_nsec += nsecs_per_sec * seconds;
+    start->tv_sec -= seconds;
+  }
+ 
+  result->tv_sec  = end->tv_sec - start->tv_sec;
+  result->tv_nsec = end->tv_nsec - start->tv_nsec;
+}
+
 /*PAGE
  *
  *  _POSIX_Timespec_to_interval
-- 
cgit v1.2.3