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authorNobuhiro Iwamatsu <iwamatsu@nigauri.org>2007-09-23 01:29:43 +0900
committerNobuhiro Iwamatsu <iwamatsu@nigauri.org>2007-09-23 01:29:43 +0900
commitb8685affe614ccf5f4ec66252b30e2e524d18948 (patch)
tree05bc55b8a4a0451e6500f1f52651d81c0f48f012 /lib_generic/div64.c
parent69df3c4da0c93017cceb25a366e794570bd0ed98 (diff)
parent66dcad3a9a53e0766d90e0084123bd8529522fb0 (diff)
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Merge git://www.denx.de/git/u-boot
Conflicts: CREDITS
Diffstat (limited to 'lib_generic/div64.c')
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diff --git a/lib_generic/div64.c b/lib_generic/div64.c
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+/*
+ * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
+ *
+ * Based on former do_div() implementation from asm-parisc/div64.h:
+ * Copyright (C) 1999 Hewlett-Packard Co
+ * Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
+ *
+ *
+ * Generic C version of 64bit/32bit division and modulo, with
+ * 64bit result and 32bit remainder.
+ *
+ * The fast case for (n>>32 == 0) is handled inline by do_div().
+ *
+ * Code generated for this function might be very inefficient
+ * for some CPUs. __div64_32() can be overridden by linking arch-specific
+ * assembly versions such as arch/ppc/lib/div64.S and arch/sh/lib/div64.S.
+ */
+
+#include <linux/types.h>
+
+uint32_t __div64_32(uint64_t *n, uint32_t base)
+{
+ uint64_t rem = *n;
+ uint64_t b = base;
+ uint64_t res, d = 1;
+ uint32_t high = rem >> 32;
+
+ /* Reduce the thing a bit first */
+ res = 0;
+ if (high >= base) {
+ high /= base;
+ res = (uint64_t) high << 32;
+ rem -= (uint64_t) (high*base) << 32;
+ }
+
+ while ((int64_t)b > 0 && b < rem) {
+ b = b+b;
+ d = d+d;
+ }
+
+ do {
+ if (rem >= b) {
+ rem -= b;
+ res += d;
+ }
+ b >>= 1;
+ d >>= 1;
+ } while (d);
+
+ *n = res;
+ return rem;
+}