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source:
trunk/third/gmp/mpz/aors_ui.h
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18191

Revision 18191, 2.8 KB checked in by ghudson, 22 years ago (diff) |
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1 | /* mpz_add_ui, mpz_sub_ui -- Add or subtract an mpz_t and an unsigned |

2 | one-word integer. |

3 | |

4 | Copyright 1991, 1993, 1994, 1996, 1999, 2000, 2001, 2002 Free Software |

5 | Foundation, Inc. |

6 | |

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

8 | |

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

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

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

12 | option) any later version. |

13 | |

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

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

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

17 | License for more details. |

18 | |

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

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

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

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

23 | |

24 | #include "gmp.h" |

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

26 | |

27 | |

28 | #ifdef OPERATION_add_ui |

29 | #define FUNCTION mpz_add_ui |

30 | #define FUNCTION2 mpz_add |

31 | #define VARIATION_CMP >= |

32 | #define VARIATION_NEG |

33 | #define VARIATION_UNNEG - |

34 | #endif |

35 | |

36 | #ifdef OPERATION_sub_ui |

37 | #define FUNCTION mpz_sub_ui |

38 | #define FUNCTION2 mpz_sub |

39 | #define VARIATION_CMP < |

40 | #define VARIATION_NEG - |

41 | #define VARIATION_UNNEG |

42 | #endif |

43 | |

44 | #ifndef FUNCTION |

45 | Error, need OPERATION_add_ui or OPERATION_sub_ui |

46 | #endif |

47 | |

48 | |

49 | void |

50 | FUNCTION (mpz_ptr w, mpz_srcptr u, unsigned long int vval) |

51 | { |

52 | mp_srcptr up; |

53 | mp_ptr wp; |

54 | mp_size_t usize, wsize; |

55 | mp_size_t abs_usize; |

56 | |

57 | #if GMP_NAIL_BITS != 0 |

58 | if (vval > GMP_NUMB_MAX) |

59 | { |

60 | mpz_t v; |

61 | mp_limb_t vl[2]; |

62 | PTR(v) = vl; |

63 | vl[0] = vval & GMP_NUMB_MASK; |

64 | vl[1] = vval >> GMP_NUMB_BITS; |

65 | SIZ(v) = 2; |

66 | FUNCTION2 (w, u, v); |

67 | return; |

68 | } |

69 | #endif |

70 | |

71 | usize = u->_mp_size; |

72 | abs_usize = ABS (usize); |

73 | |

74 | /* If not space for W (and possible carry), increase space. */ |

75 | wsize = abs_usize + 1; |

76 | if (w->_mp_alloc < wsize) |

77 | _mpz_realloc (w, wsize); |

78 | |

79 | /* These must be after realloc (U may be the same as W). */ |

80 | up = u->_mp_d; |

81 | wp = w->_mp_d; |

82 | |

83 | if (abs_usize == 0) |

84 | { |

85 | wp[0] = vval; |

86 | w->_mp_size = VARIATION_NEG (vval != 0); |

87 | return; |

88 | } |

89 | |

90 | if (usize VARIATION_CMP 0) |

91 | { |

92 | mp_limb_t cy; |

93 | cy = mpn_add_1 (wp, up, abs_usize, (mp_limb_t) vval); |

94 | wp[abs_usize] = cy; |

95 | wsize = VARIATION_NEG (abs_usize + cy); |

96 | } |

97 | else |

98 | { |

99 | /* The signs are different. Need exact comparison to determine |

100 | which operand to subtract from which. */ |

101 | if (abs_usize == 1 && up[0] < vval) |

102 | { |

103 | wp[0] = vval - up[0]; |

104 | wsize = VARIATION_NEG 1; |

105 | } |

106 | else |

107 | { |

108 | mpn_sub_1 (wp, up, abs_usize, (mp_limb_t) vval); |

109 | /* Size can decrease with at most one limb. */ |

110 | wsize = VARIATION_UNNEG (abs_usize - (wp[abs_usize - 1] == 0)); |

111 | } |

112 | } |

113 | |

114 | w->_mp_size = wsize; |

115 | } |

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