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[linux-2.6.git] / include / linux / times.h

diff --git a/include/linux/times.h b/include/linux/times.h
index e2d3020..0c5aa07 100644 (file)
--- a/include/linux/times.h
+++ b/include/linux/times.h
@@ -1,7 +1,79 @@
 #ifndef _LINUX_TIMES_H
 #define _LINUX_TIMES_H
 
-#include <linux/types.h>
+#ifdef __KERNEL__
+#include <linux/timex.h>
+#include <asm/div64.h>
+#include <asm/types.h>
+#include <asm/param.h>
+
+static inline clock_t jiffies_to_clock_t(long x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+       return x / (HZ / USER_HZ);
+#else
+       u64 tmp = (u64)x * TICK_NSEC;
+       do_div(tmp, (NSEC_PER_SEC / USER_HZ));
+       return (long)tmp;
+#endif
+}
+
+static inline unsigned long clock_t_to_jiffies(unsigned long x)
+{
+#if (HZ % USER_HZ)==0
+       if (x >= ~0UL / (HZ / USER_HZ))
+               return ~0UL;
+       return x * (HZ / USER_HZ);
+#else
+       u64 jif;
+
+       /* Don't worry about loss of precision here .. */
+       if (x >= ~0UL / HZ * USER_HZ)
+               return ~0UL;
+
+       /* .. but do try to contain it here */
+       jif = x * (u64) HZ;
+       do_div(jif, USER_HZ);
+       return jif;
+#endif
+}
+
+static inline u64 jiffies_64_to_clock_t(u64 x)
+{
+#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
+       do_div(x, HZ / USER_HZ);
+#else
+       /*
+        * There are better ways that don't overflow early,
+        * but even this doesn't overflow in hundreds of years
+        * in 64 bits, so..
+        */
+       x *= TICK_NSEC;
+       do_div(x, (NSEC_PER_SEC / USER_HZ));
+#endif
+       return x;
+}
+#endif
+
+static inline u64 nsec_to_clock_t(u64 x)
+{
+#if (NSEC_PER_SEC % USER_HZ) == 0
+       do_div(x, (NSEC_PER_SEC / USER_HZ));
+#elif (USER_HZ % 512) == 0
+       x *= USER_HZ/512;
+       do_div(x, (NSEC_PER_SEC / 512));
+#else
+       /*
+         * max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
+         * overflow after 64.99 years.
+         * exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
+         */
+       x *= 9;
+       do_div(x, (unsigned long)((9ull * NSEC_PER_SEC + (USER_HZ/2))
+                                 / USER_HZ));
+#endif
+       return x;
+}
 
 struct tms {
        clock_t tms_utime;