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Diffstat (limited to 'newlib/libc/stdlib/lldiv.c')
| -rw-r--r-- | newlib/libc/stdlib/lldiv.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/newlib/libc/stdlib/lldiv.c b/newlib/libc/stdlib/lldiv.c new file mode 100644 index 000000000..6b853e4b6 --- /dev/null +++ b/newlib/libc/stdlib/lldiv.c @@ -0,0 +1,115 @@ +/* +FUNCTION +<<lldiv>>---divide two long long integers + +INDEX + lldiv + +ANSI_SYNOPSIS + #include <stdlib.h> + lldiv_t lldiv(long long <[n]>, long long <[d]>); + +TRAD_SYNOPSIS + #include <stdlib.h> + lldiv_t lldiv(<[n]>, <[d]>) + long long <[n]>, <[d]>; + +DESCRIPTION +Divide +@tex +$n/d$, +@end tex +@ifnottex +<[n]>/<[d]>, +@end ifnottex +returning quotient and remainder as two long long integers in a structure +<<lldiv_t>>. + +RETURNS +The result is represented with the structure + +. typedef struct +. { +. long long quot; +. long long rem; +. } lldiv_t; + +where the <<quot>> field represents the quotient, and <<rem>> the +remainder. For nonzero <[d]>, if `<<<[r]> = ldiv(<[n]>,<[d]>);>>' then +<[n]> equals `<<<[r]>.rem + <[d]>*<[r]>.quot>>'. + +To divide <<long>> rather than <<long long>> values, use the similar +function <<ldiv>>. + +PORTABILITY +<<lldiv>> is ISO 9899 (C99) compatable. + +No supporting OS subroutines are required. +*/ + +/*- + * Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <stdlib.h> + +/* + * The ANSI standard says that |r.quot| <= |n/d|, where + * n/d is to be computed in infinite precision. In other + * words, we should always truncate the quotient towards + * 0, never -infinity. + * + * Machine division and remainer may work either way when + * one or both of n or d is negative. If only one is + * negative and r.quot has been truncated towards -inf, + * r.rem will have the same sign as denom and the opposite + * sign of num; if both are negative and r.quot has been + * truncated towards -inf, r.rem will be positive (will + * have the opposite sign of num). These are considered + * `wrong'. + * + * If both are num and denom are positive, r will always + * be positive. + * + * This all boils down to: + * if num >= 0, but r.rem < 0, we got the wrong answer. + * In that case, to get the right answer, add 1 to r.quot and + * subtract denom from r.rem. + */ +lldiv_t +_DEFUN (lldiv, (number, denom), + long long numer _AND long long denom) +{ + lldiv_t retval; + + retval.quot = numer / denom; + retval.rem = numer % denom; + if (numer >= 0 && retval.rem < 0) { + retval.quot++; + retval.rem -= denom; + } + return (retval); +} + |