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

Revision 18191, 3.2 KB checked in by ghudson, 22 years ago (diff) |
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1 | /* mpz_add, mpz_sub -- add or subtract integers. |

2 | |

3 | Copyright 1991, 1993, 1994, 1996, 2000, 2001 Free Software Foundation, Inc. |

4 | |

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

6 | |

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

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

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

10 | option) any later version. |

11 | |

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

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

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

15 | License for more details. |

16 | |

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

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

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

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

21 | |

22 | #include "gmp.h" |

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

24 | |

25 | |

26 | #ifdef BERKELEY_MP |

27 | |

28 | #include "mp.h" |

29 | #ifdef OPERATION_add |

30 | #define FUNCTION madd |

31 | #define VARIATION |

32 | #endif |

33 | #ifdef OPERATION_sub |

34 | #define FUNCTION msub |

35 | #define VARIATION - |

36 | #endif |

37 | #define ARGUMENTS mpz_srcptr u, mpz_srcptr v, mpz_ptr w |

38 | |

39 | #else /* normal GMP */ |

40 | |

41 | #ifdef OPERATION_add |

42 | #define FUNCTION mpz_add |

43 | #define VARIATION |

44 | #endif |

45 | #ifdef OPERATION_sub |

46 | #define FUNCTION mpz_sub |

47 | #define VARIATION - |

48 | #endif |

49 | #define ARGUMENTS mpz_ptr w, mpz_srcptr u, mpz_srcptr v |

50 | |

51 | #endif |

52 | |

53 | #ifndef FUNCTION |

54 | Error, need OPERATION_add or OPERATION_sub |

55 | #endif |

56 | |

57 | |

58 | void |

59 | FUNCTION (ARGUMENTS) |

60 | { |

61 | mp_srcptr up, vp; |

62 | mp_ptr wp; |

63 | mp_size_t usize, vsize, wsize; |

64 | mp_size_t abs_usize; |

65 | mp_size_t abs_vsize; |

66 | |

67 | usize = u->_mp_size; |

68 | vsize = VARIATION v->_mp_size; |

69 | abs_usize = ABS (usize); |

70 | abs_vsize = ABS (vsize); |

71 | |

72 | if (abs_usize < abs_vsize) |

73 | { |

74 | /* Swap U and V. */ |

75 | MPZ_SRCPTR_SWAP (u, v); |

76 | MP_SIZE_T_SWAP (usize, vsize); |

77 | MP_SIZE_T_SWAP (abs_usize, abs_vsize); |

78 | } |

79 | |

80 | /* True: ABS_USIZE >= ABS_VSIZE. */ |

81 | |

82 | /* If not space for w (and possible carry), increase space. */ |

83 | wsize = abs_usize + 1; |

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

85 | _mpz_realloc (w, wsize); |

86 | |

87 | /* These must be after realloc (u or v may be the same as w). */ |

88 | up = u->_mp_d; |

89 | vp = v->_mp_d; |

90 | wp = w->_mp_d; |

91 | |

92 | if ((usize ^ vsize) < 0) |

93 | { |

94 | /* U and V have different sign. Need to compare them to determine |

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

96 | |

97 | /* This test is right since ABS_USIZE >= ABS_VSIZE. */ |

98 | if (abs_usize != abs_vsize) |

99 | { |

100 | mpn_sub (wp, up, abs_usize, vp, abs_vsize); |

101 | wsize = abs_usize; |

102 | MPN_NORMALIZE (wp, wsize); |

103 | if (usize < 0) |

104 | wsize = -wsize; |

105 | } |

106 | else if (mpn_cmp (up, vp, abs_usize) < 0) |

107 | { |

108 | mpn_sub_n (wp, vp, up, abs_usize); |

109 | wsize = abs_usize; |

110 | MPN_NORMALIZE (wp, wsize); |

111 | if (usize >= 0) |

112 | wsize = -wsize; |

113 | } |

114 | else |

115 | { |

116 | mpn_sub_n (wp, up, vp, abs_usize); |

117 | wsize = abs_usize; |

118 | MPN_NORMALIZE (wp, wsize); |

119 | if (usize < 0) |

120 | wsize = -wsize; |

121 | } |

122 | } |

123 | else |

124 | { |

125 | /* U and V have same sign. Add them. */ |

126 | mp_limb_t cy_limb = mpn_add (wp, up, abs_usize, vp, abs_vsize); |

127 | wp[abs_usize] = cy_limb; |

128 | wsize = abs_usize + cy_limb; |

129 | if (usize < 0) |

130 | wsize = -wsize; |

131 | } |

132 | |

133 | w->_mp_size = wsize; |

134 | } |

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