1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 /* 28 * Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. 29 * Copyright (c) 1988 AT&T 30 * All Rights Reserved 31 */ 32 33 #pragma ident "%Z%%M% %I% %E% SMI" 34 35 /* 36 * Establish the default settings for the floating-point state for a C language 37 * program: 38 * rounding mode -- round to nearest default by OS, 39 * exceptions enabled -- all masked 40 * sticky bits -- all clear by default by OS. 41 * precision control -- double extended 42 */ 43 44 #pragma weak _fpstart = __fpstart 45 46 #include "synonyms.h" 47 #include <sys/types.h> 48 #include <sys/sysi86.h> /* for SI86FPHW/SI86FPSTART definitions */ 49 #include <sys/fp.h> /* for FPU_CW_INIT and SSE_MXCSR_INIT */ 50 51 int __flt_rounds; /* ANSI rounding mode */ 52 53 void 54 __fpstart() 55 { 56 int _fp_hw; /* default: bss: 0 == no hardware */ 57 58 /* 59 * query OS for HW status and ensure the x87 and (optional) 60 * SSE control words are (will be) set correctly. 61 * This "cannot fail". 62 */ 63 (void) sysi86(SI86FPSTART, 64 &_fp_hw, FPU_CW_INIT, SSE_MXCSR_INIT); 65 66 /* 67 * At this point the x87 fp environment that has been (or more 68 * hopefully, will be) established by the kernel is: 69 * 70 * affine infinity 0x1000 71 * round to nearest 0x0000 72 * 64-bit doubles 0x0300 73 * precision, underflow, overflow, zero-divide, denorm, invalid masked 74 * 0x003f 75 * 76 * which conforms to the 4th edition i386 ABI definition. 77 * 78 * Additionally, if we have SSE hardware, we've also masked all 79 * the same traps, and have round to nearest. 80 */ 81 82 __flt_rounds = 1; /* ANSI way of saying round-to-nearest */ 83 } 84