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

Revision 18191, 2.7 KB checked in by ghudson, 22 years ago (diff) |
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1 | /* mpz_mul_ui/si (product, multiplier, small_multiplicand) -- Set PRODUCT to |

2 | MULTIPLICATOR times SMALL_MULTIPLICAND. |

3 | |

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

5 | 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_mul_si |

29 | #define FUNCTION mpz_mul_si |

30 | #define MULTIPLICAND_UNSIGNED |

31 | #define MULTIPLICAND_ABS(x) ((unsigned long) ABS(x)) |

32 | #endif |

33 | |

34 | #ifdef OPERATION_mul_ui |

35 | #define FUNCTION mpz_mul_ui |

36 | #define MULTIPLICAND_UNSIGNED unsigned |

37 | #define MULTIPLICAND_ABS(x) x |

38 | #endif |

39 | |

40 | #ifndef FUNCTION |

41 | Error, error, unrecognised OPERATION |

42 | #endif |

43 | |

44 | |

45 | void |

46 | FUNCTION (mpz_ptr prod, mpz_srcptr mult, |

47 | MULTIPLICAND_UNSIGNED long int small_mult) |

48 | { |

49 | mp_size_t size = SIZ(mult); |

50 | mp_size_t sign_product = size; |

51 | mp_limb_t sml; |

52 | mp_limb_t cy; |

53 | mp_ptr pp; |

54 | |

55 | if (size == 0 || small_mult == 0) |

56 | { |

57 | SIZ(prod) = 0; |

58 | return; |

59 | } |

60 | |

61 | size = ABS (size); |

62 | |

63 | sml = MULTIPLICAND_ABS (small_mult); |

64 | |

65 | if (small_mult <= GMP_NUMB_MAX) |

66 | { |

67 | MPZ_REALLOC (prod, size + 1); |

68 | pp = PTR(prod); |

69 | cy = mpn_mul_1 (pp, PTR(mult), size, sml & GMP_NUMB_MASK); |

70 | pp[size] = cy; |

71 | size += cy != 0; |

72 | } |

73 | #if GMP_NAIL_BITS != 0 |

74 | else |

75 | { |

76 | /* Operand too large for the current nails size. Use temporary for |

77 | intermediate products, to allow prod and mult being identical. */ |

78 | mp_ptr tp; |

79 | TMP_DECL (mark); |

80 | TMP_MARK (mark); |

81 | |

82 | tp = TMP_ALLOC_LIMBS (size + 2); |

83 | |

84 | cy = mpn_mul_1 (tp, PTR(mult), size, sml & GMP_NUMB_MASK); |

85 | tp[size] = cy; |

86 | cy = mpn_addmul_1 (tp + 1, PTR(mult), size, sml >> GMP_NUMB_BITS); |

87 | tp[size + 1] = cy; |

88 | size += 2; |

89 | MPN_NORMALIZE_NOT_ZERO (tp, size); /* too general, need to trim one or two limb */ |

90 | MPZ_REALLOC (prod, size); |

91 | pp = PTR(prod); |

92 | MPN_COPY (pp, tp, size); |

93 | TMP_FREE (mark); |

94 | } |

95 | #endif |

96 | |

97 | SIZ(prod) = ((sign_product < 0) ^ (small_mult < 0)) ? -size : size; |

98 | } |

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