ashrdi3.c 1.3 KB

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  1. /*===-- ashrdi3.c - Implement __ashrdi3 -----------------------------------===
  2. *
  3. * The LLVM Compiler Infrastructure
  4. *
  5. * This file is dual licensed under the MIT and the University of Illinois Open
  6. * Source Licenses. See LICENSE.TXT for details.
  7. *
  8. * ===----------------------------------------------------------------------===
  9. *
  10. * This file implements __ashrdi3 for the compiler_rt library.
  11. *
  12. * ===----------------------------------------------------------------------===
  13. */
  14. #include "int_lib.h"
  15. /* Returns: arithmetic a >> b */
  16. /* Precondition: 0 <= b < bits_in_dword */
  17. ARM_EABI_FNALIAS(lasr, ashrdi3)
  18. COMPILER_RT_ABI di_int
  19. __ashrdi3(di_int a, si_int b)
  20. {
  21. const int bits_in_word = (int)(sizeof(si_int) * CHAR_BIT);
  22. dwords input;
  23. dwords result;
  24. input.all = a;
  25. if (b & bits_in_word) /* bits_in_word <= b < bits_in_dword */
  26. {
  27. /* result.s.high = input.s.high < 0 ? -1 : 0 */
  28. result.s.high = input.s.high >> (bits_in_word - 1);
  29. result.s.low = input.s.high >> (b - bits_in_word);
  30. }
  31. else /* 0 <= b < bits_in_word */
  32. {
  33. if (b == 0)
  34. return a;
  35. result.s.high = input.s.high >> b;
  36. result.s.low = (input.s.high << (bits_in_word - b)) | (input.s.low >> b);
  37. }
  38. return result.all;
  39. }