modti3.c 1.1 KB

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  1. /* ===-- modti3.c - Implement __modti3 -------------------------------------===
  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 __modti3 for the compiler_rt library.
  11. *
  12. * ===----------------------------------------------------------------------===
  13. */
  14. #include "int_lib.h"
  15. #ifdef CRT_HAS_128BIT
  16. /*Returns: a % b */
  17. COMPILER_RT_ABI ti_int
  18. __modti3(ti_int a, ti_int b)
  19. {
  20. const int bits_in_tword_m1 = (int)(sizeof(ti_int) * CHAR_BIT) - 1;
  21. ti_int s = b >> bits_in_tword_m1; /* s = b < 0 ? -1 : 0 */
  22. b = (b ^ s) - s; /* negate if s == -1 */
  23. s = a >> bits_in_tword_m1; /* s = a < 0 ? -1 : 0 */
  24. a = (a ^ s) - s; /* negate if s == -1 */
  25. tu_int r;
  26. __udivmodti4(a, b, &r);
  27. return ((ti_int)r ^ s) - s; /* negate if s == -1 */
  28. }
  29. #endif /* CRT_HAS_128BIT */