diff options
Diffstat (limited to 'usr/src/lib/libm/common/m9x/round.c')
-rw-r--r-- | usr/src/lib/libm/common/m9x/round.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/usr/src/lib/libm/common/m9x/round.c b/usr/src/lib/libm/common/m9x/round.c new file mode 100644 index 0000000000..f4f5a48f2f --- /dev/null +++ b/usr/src/lib/libm/common/m9x/round.c @@ -0,0 +1,76 @@ +/* + * 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. + */ + +#if defined(ELFOBJ) +#pragma weak round = __round +#endif + +#include "libm.h" + +double +round(double x) { + union { + unsigned i[2]; + double d; + } xx; + unsigned hx, sx, i; + + xx.d = x; + hx = xx.i[HIWORD] & ~0x80000000; + sx = xx.i[HIWORD] & 0x80000000; + if (hx < 0x43300000) { /* |x| < 2^52 */ + if (hx < 0x3ff00000) { /* |x| < 1 */ + if (hx >= 0x3fe00000) + return (sx ? -1.0 : 1.0); + return (sx ? -0.0 : 0.0); + } + + /* round x at the integer bit */ + if (hx < 0x41300000) { + i = 1 << (0x412 - (hx >> 20)); + xx.i[HIWORD] = (xx.i[HIWORD] + i) & ~(i | (i - 1)); + xx.i[LOWORD] = 0; + } else { + i = 1 << (0x432 - (hx >> 20)); + xx.i[LOWORD] += i; + if (xx.i[LOWORD] < i) + xx.i[HIWORD]++; + xx.i[LOWORD] &= ~(i | (i - 1)); + } + return (xx.d); + } else if (hx < 0x7ff00000) + return (x); + else +#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) + return (hx >= 0x7ff80000 ? x : x + x); + /* assumes sparc-like QNaN */ +#else + return (x + x); +#endif +} |