| /* |
| * 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> |
| |
| #include <asm-generic/div64.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; |
| } |