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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 6301b4b30229079bfaff8c46a5c2321f64dec3a0 / . / lib / ldiv.c

Tom Rini | 83d290c | 2018-05-06 17:58:06 -0400 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0+ |

wdenk | 4a5b6a3 | 2001-04-28 17:59:11 +0000 | [diff] [blame] | 2 | /* Copyright (C) 1992, 1997 Free Software Foundation, Inc. |

3 | This file is part of the GNU C Library. | ||||

Wolfgang Denk | a53002f | 2013-07-08 11:58:49 +0200 | [diff] [blame] | 4 | */ |

wdenk | 4a5b6a3 | 2001-04-28 17:59:11 +0000 | [diff] [blame] | 5 | |

6 | typedef struct { | ||||

wdenk | 8bde7f7 | 2003-06-27 21:31:46 +0000 | [diff] [blame] | 7 | long quot; |

8 | long rem; | ||||

wdenk | 4a5b6a3 | 2001-04-28 17:59:11 +0000 | [diff] [blame] | 9 | } ldiv_t; |

10 | /* Return the `ldiv_t' representation of NUMER over DENOM. */ | ||||

11 | ldiv_t | ||||

12 | ldiv (long int numer, long int denom) | ||||

13 | { | ||||

14 | ldiv_t result; | ||||

15 | |||||

16 | result.quot = numer / denom; | ||||

17 | result.rem = numer % denom; | ||||

18 | |||||

19 | /* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where | ||||

20 | NUMER / DENOM is to be computed in infinite precision. In | ||||

21 | other words, we should always truncate the quotient towards | ||||

22 | zero, never -infinity. Machine division and remainer may | ||||

23 | work either way when one or both of NUMER or DENOM is | ||||

24 | negative. If only one is negative and QUOT has been | ||||

25 | truncated towards -infinity, REM will have the same sign as | ||||

26 | DENOM and the opposite sign of NUMER; if both are negative | ||||

27 | and QUOT has been truncated towards -infinity, REM will be | ||||

28 | positive (will have the opposite sign of NUMER). These are | ||||

29 | considered `wrong'. If both are NUM and DENOM are positive, | ||||

30 | RESULT will always be positive. This all boils down to: if | ||||

31 | NUMER >= 0, but REM < 0, we got the wrong answer. In that | ||||

32 | case, to get the right answer, add 1 to QUOT and subtract | ||||

33 | DENOM from REM. */ | ||||

34 | |||||

35 | if (numer >= 0 && result.rem < 0) | ||||

36 | { | ||||

37 | ++result.quot; | ||||

38 | result.rem -= denom; | ||||

39 | } | ||||

40 | |||||

41 | return result; | ||||

42 | } |