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, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. 24 * Copyright (c) 1988 AT&T 25 * All Rights Reserved 26 */ 27 28 /* 29 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 30 * Use is subject to license terms. 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 * Set _fp_hw according to what floating-point hardware is available. 43 * Set _sse_hw according to what SSE hardware is available. 44 * Set __flt_rounds according to the rounding mode. 45 */ 46 47 #pragma weak _fpstart = __fpstart 48 49 #include "synonyms.h" 50 #include <sys/types.h> 51 #include <sys/sysi86.h> /* for SI86FPHW/SI86FPSTART definitions */ 52 #include <sys/fp.h> /* for FPU_CW_INIT and SSE_MXCSR_INIT */ 53 54 extern int _private_sysi86(); 55 extern int __fltrounds(); 56 57 int _fp_hw; /* default: bss: 0 == no hardware */ 58 int _sse_hw; /* default: bss: 0 == no sse */ 59 int __flt_rounds; /* ANSI rounding mode */ 60 61 void 62 __fpstart() 63 { 64 /* 65 * query OS for HW status and ensure the x87 and (optional) 66 * SSE control words are (will be) set correctly. 67 */ 68 if ((_sse_hw = _private_sysi86(SI86FPSTART, 69 &_fp_hw, FPU_CW_INIT, SSE_MXCSR_INIT)) == -1) { 70 extern void _putcw(); 71 72 /* 73 * (fallback to old syscall on old kernels) 74 */ 75 _sse_hw = 0; 76 (void) _private_sysi86(SI86FPHW, &_fp_hw); 77 _putcw(0x133f); 78 } 79 80 /* 81 * At this point the x87 fp environment that has been (or more 82 * hopefully, will be) established by the kernel is: 83 * 84 * affine infinity 0x1000 85 * round to nearest 0x0000 86 * 64-bit doubles 0x0300 87 * precision, underflow, overflow, zero-divide, denorm, invalid masked 88 * 0x003f 89 * 90 * which conforms to the 4th edition i386 ABI definition. 91 * 92 * Additionally, if we have SSE hardware, we've also masked all 93 * the same traps, and have round to nearest. 94 */ 95 96 __flt_rounds = 1; /* ANSI way of saying round-to-nearest */ 97 } 98