memmove_64.c 1.2 KB

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  1. /* Normally compiler builtins are used, but sometimes the compiler calls out
  2. of line code. Based on asm-i386/string.h.
  3. */
  4. #define _STRING_C
  5. #include <linux/string.h>
  6. #include <linux/module.h>
  7. #undef memmove
  8. void *memmove(void *dest, const void *src, size_t count)
  9. {
  10. unsigned long d0, d1, d2, d3;
  11. if (dest < src) {
  12. if ((dest + count) < src)
  13. return memcpy(dest, src, count);
  14. else
  15. __asm__ __volatile__(
  16. "movq %0, %3\n\t"
  17. "shr $3, %0\n\t"
  18. "andq $7, %3\n\t"
  19. "rep\n\t"
  20. "movsq\n\t"
  21. "movq %3, %0\n\t"
  22. "rep\n\t"
  23. "movsb"
  24. : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3)
  25. :"0" (count),
  26. "1" (src),
  27. "2" (dest)
  28. :"memory");
  29. } else {
  30. if((src + count) < dest)
  31. return memcpy(dest, src, count);
  32. else
  33. __asm__ __volatile__(
  34. "movq %0, %3\n\t"
  35. "lea -8(%1, %0), %1\n\t"
  36. "lea -8(%2, %0), %2\n\t"
  37. "shr $3, %0\n\t"
  38. "andq $7, %3\n\t"
  39. "std\n\t"
  40. "rep\n\t"
  41. "movsq\n\t"
  42. "lea 7(%1), %1\n\t"
  43. "lea 7(%2), %2\n\t"
  44. "movq %3, %0\n\t"
  45. "rep\n\t"
  46. "movsb\n\t"
  47. "cld"
  48. : "=&c" (d0), "=&S" (d1), "=&D" (d2), "=r" (d3)
  49. :"0" (count),
  50. "1" (src),
  51. "2" (dest)
  52. :"memory");
  53. }
  54. return dest;
  55. }
  56. EXPORT_SYMBOL(memmove);