/*
* 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 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
/*
* Copyright (c) 1990, 1991 UNIX System Laboratories, Inc.
* Copyright (c) 1988 AT&T
* All Rights Reserved
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Establish the default settings for the floating-point state for a C language
* program:
* rounding mode -- round to nearest default by OS,
* exceptions enabled -- all masked
* sticky bits -- all clear by default by OS.
* precision control -- double extended
*/
#pragma weak _fpstart = __fpstart
#include "lint.h"
#include <sys/types.h>
#include <sys/sysi86.h> /* for SI86FPHW/SI86FPSTART definitions */
#include <sys/fp.h> /* for FPU_CW_INIT and SSE_MXCSR_INIT */
int __flt_rounds; /* ANSI rounding mode */
void
__fpstart()
{
int _fp_hw; /* default: bss: 0 == no hardware */
/*
* query OS for HW status and ensure the x87 and (optional)
* SSE control words are (will be) set correctly.
* This "cannot fail".
*/
(void) sysi86(SI86FPSTART,
&_fp_hw, FPU_CW_INIT, SSE_MXCSR_INIT);
/*
* At this point the x87 fp environment that has been (or more
* hopefully, will be) established by the kernel is:
*
* affine infinity 0x1000
* round to nearest 0x0000
* 64-bit doubles 0x0300
* precision, underflow, overflow, zero-divide, denorm, invalid masked
* 0x003f
*
* which conforms to the 4th edition i386 ABI definition.
*
* Additionally, if we have SSE hardware, we've also masked all
* the same traps, and have round to nearest.
*/
__flt_rounds = 1; /* ANSI way of saying round-to-nearest */
}