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Diffstat (limited to 'lib/ldiv.c')
| -rw-r--r-- | lib/ldiv.c | 55 | 
1 files changed, 55 insertions, 0 deletions
| diff --git a/lib/ldiv.c b/lib/ldiv.c new file mode 100644 index 000000000..5d231a2a6 --- /dev/null +++ b/lib/ldiv.c @@ -0,0 +1,55 @@ +/* Copyright (C) 1992, 1997 Free Software Foundation, Inc. +   This file is part of the GNU C Library. + +   The GNU C Library is free software; you can redistribute it and/or +   modify it under the terms of the GNU Library General Public License as +   published by the Free Software Foundation; either version 2 of the +   License, or (at your option) any later version. + +   The GNU C Library is distributed in the hope that it will be useful, +   but WITHOUT ANY WARRANTY; without even the implied warranty of +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU +   Library General Public License for more details. + +   You should have received a copy of the GNU Library General Public +   License along with the GNU C Library; see the file COPYING.LIB.  If not, +   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +   Boston, MA 02111-1307, USA.  */ + +typedef struct { +	long    quot; +	long    rem; +} ldiv_t; +/* Return the `ldiv_t' representation of NUMER over DENOM.  */ +ldiv_t +ldiv (long int numer, long int denom) +{ +  ldiv_t result; + +  result.quot = numer / denom; +  result.rem = numer % denom; + +  /* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where +     NUMER / DENOM is to be computed in infinite precision.  In +     other words, we should always truncate the quotient towards +     zero, never -infinity.  Machine division and remainer may +     work either way when one or both of NUMER or DENOM is +     negative.  If only one is negative and QUOT has been +     truncated towards -infinity, REM will have the same sign as +     DENOM and the opposite sign of NUMER; if both are negative +     and QUOT has been truncated towards -infinity, REM will be +     positive (will have the opposite sign of NUMER).  These are +     considered `wrong'.  If both are NUM and DENOM are positive, +     RESULT will always be positive.  This all boils down to: if +     NUMER >= 0, but REM < 0, we got the wrong answer.  In that +     case, to get the right answer, add 1 to QUOT and subtract +     DENOM from REM.  */ + +  if (numer >= 0 && result.rem < 0) +    { +      ++result.quot; +      result.rem -= denom; +    } + +  return result; +} |