div64.h 1.5 KB

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  1. #ifndef _ASM_GENERIC_DIV64_H
  2. #define _ASM_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. #include <linux/types.h>
  20. #include <linux/compiler.h>
  21. #if BITS_PER_LONG == 64
  22. # define do_div(n,base) ({ \
  23. uint32_t __base = (base); \
  24. uint32_t __rem; \
  25. __rem = ((uint64_t)(n)) % __base; \
  26. (n) = ((uint64_t)(n)) / __base; \
  27. __rem; \
  28. })
  29. static inline uint64_t div64_64(uint64_t dividend, uint64_t divisor)
  30. {
  31. return dividend / divisor;
  32. }
  33. #elif BITS_PER_LONG == 32
  34. extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor);
  35. /* The unnecessary pointer compare is there
  36. * to check for type safety (n must be 64bit)
  37. */
  38. # define do_div(n,base) ({ \
  39. uint32_t __base = (base); \
  40. uint32_t __rem; \
  41. (void)(((typeof((n)) *)0) == ((uint64_t *)0)); \
  42. if (likely(((n) >> 32) == 0)) { \
  43. __rem = (uint32_t)(n) % __base; \
  44. (n) = (uint32_t)(n) / __base; \
  45. } else \
  46. __rem = __div64_32(&(n), __base); \
  47. __rem; \
  48. })
  49. extern uint64_t div64_64(uint64_t dividend, uint64_t divisor);
  50. #else /* BITS_PER_LONG == ?? */
  51. # error do_div() does not yet support the C64
  52. #endif /* BITS_PER_LONG */
  53. #endif /* _ASM_GENERIC_DIV64_H */