Merge branch 'for-2.6.37' into HEAD

[karo-tx-linux.git] / lib / div64.c

diff --git a/lib/div64.c b/lib/div64.c
index b71cf93c529adaa3364afa4a1b997c54cc9ef363..5b4919191778bb4f2224e798037f23e9dd5ea2ad 100644 (file)
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -16,9 +16,8 @@
  * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.
  */
 
-#include <linux/types.h>
 #include <linux/module.h>
-#include <asm/div64.h>
+#include <linux/math64.h>
 
 /* Not needed on 64bit architectures */
 #if BITS_PER_LONG == 32
@@ -58,24 +57,86 @@ uint32_t __attribute__((weak)) __div64_32(uint64_t *n, uint32_t base)
 
 EXPORT_SYMBOL(__div64_32);
 
-/* 64bit divisor, dividend and result. dynamic precision */
-uint64_t div64_64(uint64_t dividend, uint64_t divisor)
+#ifndef div_s64_rem
+s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder)
 {
-       uint32_t high, d;
+       u64 quotient;
 
-       high = divisor >> 32;
-       if (high) {
-               unsigned int shift = fls(high);
+       if (dividend < 0) {
+               quotient = div_u64_rem(-dividend, abs(divisor), (u32 *)remainder);
+               *remainder = -*remainder;
+               if (divisor > 0)
+                       quotient = -quotient;
+       } else {
+               quotient = div_u64_rem(dividend, abs(divisor), (u32 *)remainder);
+               if (divisor < 0)
+                       quotient = -quotient;
+       }
+       return quotient;
+}
+EXPORT_SYMBOL(div_s64_rem);
+#endif
+
+/**
+ * div64_u64 - unsigned 64bit divide with 64bit divisor
+ * @dividend:  64bit dividend
+ * @divisor:   64bit divisor
+ *
+ * This implementation is a modified version of the algorithm proposed
+ * by the book 'Hacker's Delight'.  The original source and full proof
+ * can be found here and is available for use without restriction.
+ *
+ * 'http://www.hackersdelight.org/HDcode/newCode/divDouble.c'
+ */
+#ifndef div64_u64
+u64 div64_u64(u64 dividend, u64 divisor)
+{
+       u32 high = divisor >> 32;
+       u64 quot;
 
-               d = divisor >> shift;
-               dividend >>= shift;
-       } else
-               d = divisor;
+       if (high == 0) {
+               quot = div_u64(dividend, divisor);
+       } else {
+               int n = 1 + fls(high);
+               quot = div_u64(dividend >> n, divisor >> n);
 
-       do_div(dividend, d);
+               if (quot != 0)
+                       quot--;
+               if ((dividend - quot * divisor) >= divisor)
+                       quot++;
+       }
 
-       return dividend;
+       return quot;
 }
-EXPORT_SYMBOL(div64_64);
+EXPORT_SYMBOL(div64_u64);
+#endif
+
+/**
+ * div64_s64 - signed 64bit divide with 64bit divisor
+ * @dividend:  64bit dividend
+ * @divisor:   64bit divisor
+ */
+#ifndef div64_s64
+s64 div64_s64(s64 dividend, s64 divisor)
+{
+       s64 quot, t;
+
+       quot = div64_u64(abs64(dividend), abs64(divisor));
+       t = (dividend ^ divisor) >> 63;
+
+       return (quot ^ t) - t;
+}
+EXPORT_SYMBOL(div64_s64);
+#endif
 
 #endif /* BITS_PER_LONG == 32 */
+
+/*
+ * Iterative div/mod for use when dividend is not expected to be much
+ * bigger than divisor.
+ */
+u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
+{
+       return __iter_div_u64_rem(dividend, divisor, remainder);
+}
+EXPORT_SYMBOL(iter_div_u64_rem);