#
source:
trunk/third/gmp/mpz/fdiv_q_ui.c
@
18191

Revision 18191, 2.2 KB checked in by ghudson, 22 years ago (diff) |
---|

Line | |
---|---|

1 | /* mpz_fdiv_q_ui -- Division rounding the quotient towards -infinity. |

2 | The remainder gets the same sign as the denominator. |

3 | |

4 | Copyright 1994, 1995, 1996, 1999, 2001, 2002 Free Software Foundation, Inc. |

5 | |

6 | This file is part of the GNU MP Library. |

7 | |

8 | The GNU MP Library is free software; you can redistribute it and/or modify |

9 | it under the terms of the GNU Lesser General Public License as published by |

10 | the Free Software Foundation; either version 2.1 of the License, or (at your |

11 | option) any later version. |

12 | |

13 | The GNU MP Library is distributed in the hope that it will be useful, but |

14 | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |

15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |

16 | License for more details. |

17 | |

18 | You should have received a copy of the GNU Lesser General Public License |

19 | along with the GNU MP Library; see the file COPYING.LIB. If not, write to |

20 | the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |

21 | MA 02111-1307, USA. */ |

22 | |

23 | #include "gmp.h" |

24 | #include "gmp-impl.h" |

25 | |

26 | unsigned long int |

27 | mpz_fdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor) |

28 | { |

29 | mp_size_t ns, nn, qn; |

30 | mp_ptr np, qp; |

31 | mp_limb_t rl; |

32 | |

33 | if (divisor == 0) |

34 | DIVIDE_BY_ZERO; |

35 | |

36 | ns = SIZ(dividend); |

37 | if (ns == 0) |

38 | { |

39 | SIZ(quot) = 0; |

40 | return 0; |

41 | } |

42 | |

43 | nn = ABS(ns); |

44 | MPZ_REALLOC (quot, nn); |

45 | qp = PTR(quot); |

46 | np = PTR(dividend); |

47 | |

48 | #if GMP_NAIL_BITS != 0 |

49 | if (divisor > GMP_NUMB_MAX) |

50 | { |

51 | mp_limb_t dp[2], rp[2]; |

52 | |

53 | if (nn == 1) /* tdiv_qr requirements; tested above for 0 */ |

54 | { |

55 | qp[0] = 0; |

56 | rl = np[0]; |

57 | qn = 1; /* a white lie, fixed below */ |

58 | } |

59 | else |

60 | { |

61 | dp[0] = divisor & GMP_NUMB_MASK; |

62 | dp[1] = divisor >> GMP_NUMB_BITS; |

63 | mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2); |

64 | rl = rp[0] + (rp[1] << GMP_NUMB_BITS); |

65 | qn = nn - 2 + 1; |

66 | } |

67 | |

68 | if (rl != 0 && ns < 0) |

69 | { |

70 | mpn_incr_u (qp, (mp_limb_t) 1); |

71 | rl = divisor - rl; |

72 | } |

73 | |

74 | qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0; |

75 | } |

76 | else |

77 | #endif |

78 | { |

79 | rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor); |

80 | |

81 | if (rl != 0 && ns < 0) |

82 | { |

83 | mpn_incr_u (qp, (mp_limb_t) 1); |

84 | rl = divisor - rl; |

85 | } |

86 | |

87 | qn = nn - (qp[nn - 1] == 0); |

88 | } |

89 | |

90 | SIZ(quot) = ns >= 0 ? qn : -qn; |

91 | return rl; |

92 | } |

**Note:**See TracBrowser for help on using the repository browser.