fenv.c - vx32 - Local 9vx git repository for patches.
 (HTM) git clone git://r-36.net/vx32
 (DIR) Log
 (DIR) Files
 (DIR) Refs
       ---
       fenv.c (2255B)
       ---
            1 /*-
            2  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
            3  * All rights reserved.
            4  *
            5  * Redistribution and use in source and binary forms, with or without
            6  * modification, are permitted provided that the following conditions
            7  * are met:
            8  * 1. Redistributions of source code must retain the above copyright
            9  *    notice, this list of conditions and the following disclaimer.
           10  * 2. Redistributions in binary form must reproduce the above copyright
           11  *    notice, this list of conditions and the following disclaimer in the
           12  *    documentation and/or other materials provided with the distribution.
           13  *
           14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
           15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
           16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
           17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
           18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
           19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
           20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
           21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
           22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
           23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
           24  * SUCH DAMAGE.
           25  *
           26  * $FreeBSD: src/lib/msun/amd64/fenv.c,v 1.2 2004/06/11 02:35:19 das Exp $
           27  */
           28 
           29 #include <fenv.h>
           30 
           31 int
           32 fesetexceptflag(const fexcept_t *flagp, int excepts)
           33 {
           34         unsigned __mxcsr;
           35 
           36         __stmxcsr(&__mxcsr);
           37         __mxcsr &= ~excepts;
           38         __mxcsr |= *flagp & excepts;
           39         __ldmxcsr(__mxcsr);
           40 
           41         return (0);
           42 }
           43 
           44 int
           45 feraiseexcept(int excepts)
           46 {
           47         fexcept_t ex = excepts;
           48 
           49         fesetexceptflag(&ex, excepts);
           50 
           51         // The DIVSS instruction can generate all SSE2 exceptions,
           52         // which hopefully means it will check all exception flags.
           53         // asm volatile("divss %0,%0" : : "x" (1.0));
           54 
           55         return (0);
           56 }
           57 
           58 int
           59 feholdexcept(fenv_t *envp)
           60 {
           61         int mxcsr;
           62 
           63         __stmxcsr(&mxcsr);
           64         *envp = mxcsr;
           65         mxcsr &= ~FE_ALL_EXCEPT;
           66         mxcsr |= FE_ALL_EXCEPT << 7;
           67         __ldmxcsr(mxcsr);
           68         return (0);
           69 }
           70 
           71 int
           72 feupdateenv(const fenv_t *envp)
           73 {
           74         int mxcsr;
           75 
           76         __stmxcsr(&mxcsr);
           77         fesetenv(envp);
           78         feraiseexcept(mxcsr & FE_ALL_EXCEPT);
           79         return (0);
           80 }
           81