diff options
Diffstat (limited to 'usr/src/lib/libm/common/C/remainder.c')
-rw-r--r-- | usr/src/lib/libm/common/C/remainder.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/C/remainder.c b/usr/src/lib/libm/common/C/remainder.c new file mode 100644 index 0000000000..ababc45cfb --- /dev/null +++ b/usr/src/lib/libm/common/C/remainder.c @@ -0,0 +1,87 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License (the "License"). + * You may not use this file except in compliance with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2011 Nexenta Systems, Inc. All rights reserved. + */ +/* + * Copyright 2006 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma weak remainder = __remainder + +/* + * remainder(x,p) + * Code originated from 4.3bsd. + * Modified by K.C. Ng for SUN 4.0 libm. + * Return : + * returns x REM p = x - [x/p]*p as if in infinite precise arithmetic, + * where [x/p] is the (inifinite bit) integer nearest x/p (in half way + * case choose the even one). + * Method : + * Based on fmod() return x-[x/p]chopped*p exactly. + */ + +#include "libm.h" + +static const double zero = 0.0, half = 0.5; + +double +remainder(double x, double p) { + double halfp; + int ix, hx, hp; + + ix = ((int *)&x)[HIWORD]; + hx = ix & ~0x80000000; + hp = ((int *)&p)[HIWORD] & ~0x80000000; + + if (hp > 0x7ff00000 || (hp == 0x7ff00000 && ((int *)&p)[LOWORD] != 0)) + return (x * p); + if (hx > 0x7ff00000 || (hx == 0x7ff00000 && ((int *)&x)[LOWORD] != 0)) + return (x * p); + + if ((hp | ((int *)&p)[LOWORD]) == 0 || hx == 0x7ff00000) + return (_SVID_libm_err(x, p, 28)); + + p = fabs(p); + if (hp < 0x7fe00000) + x = fmod(x, p + p); + x = fabs(x); + if (hp < 0x00200000) { + if (x + x > p) { + if (x == p) /* avoid x-x=-0 in RM mode */ + return ((ix < 0)? -zero : zero); + x -= p; + if (x + x >= p) + x -= p; + } + } else { + halfp = half * p; + if (x > halfp) { + if (x == p) /* avoid x-x=-0 in RM mode */ + return ((ix < 0)? -zero : zero); + x -= p; + if (x >= halfp) + x -= p; + } + } + return ((ix < 0)? -x : x); +} |