LXR coreboot/src/include/arch-generic/div64.h

   1#ifndef ARCH_GENERIC_DIV64_H
   2#define ARCH_GENERIC_DIV64_H
   3/*
   4 * Copyright (C) 2003 Bernardo Innocenti <bernie@develer.com>
   5 * Based on former asm-ppc/div64.h and asm-m68knommu/div64.h
   6 *
   7 * The semantics of do_div() are:
   8 *
   9 * uint32_t do_div(uint64_t *n, uint32_t base)
  10 * {
  11 *      uint32_t remainder = *n % base;
  12 *      *n = *n / base;
  13 *      return remainder;
  14 * }
  15 *
  16 * NOTE: macro parameter n is evaluated multiple times,
  17 *       beware of side effects!
  18 */
  19
  20#ifndef ULONG_MAX
  21#include <limits.h>
  22#endif
  23#include <stdint.h>
  24
  25#if ULONG_MAX == 4294967295
  26
  27extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
  28
  29/* The unnecessary pointer compare is there
  30 * to check for type safety (n must be 64bit)
  31 */
  32# define do_div(n,base) ({                              \
  33        uint32_t __base = (base);                       \
  34        uint32_t __rem;                                 \
  35        (void)(((typeof((n)) *)0) == ((uint64_t *)0));  \
  36        if (((n) >> 32) == 0) {                         \
  37                __rem = (uint32_t)(n) % __base;         \
  38                (n) = (uint32_t)(n) / __base;           \
  39        } else                                          \
  40                __rem = __div64_32(&(n), __base);       \
  41        __rem;                                          \
  42 })
  43
  44#elif ULONG_MAX == 18446744073709551615
  45
  46# define do_div(n,base) ({                                      \
  47        uint32_t __base = (base);                               \
  48        uint32_t __rem;                                         \
  49        __rem = ((uint64_t)(n)) % __base;                       \
  50        (n) = ((uint64_t)(n)) / __base;                         \
  51        __rem;                                                  \
  52 })
  53
  54
  55#else /* BITS_PER_LONG == ?? */
  56
  57# error do_div() does not yet support the C64
  58
  59#endif /* BITS_PER_LONG */
  60
  61#endif /* ARCH_GENERIC_DIV64_H */
  62