arch/x86_64-all/mlib/fenv.c

   1 /*-
   2  * Copyright (c) 2004-2005 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 1.4 2007/01/05 07:15:26 das Exp $
  27  */
  28
  29 #include <sys/cdefs.h>
  30 #include <sys/types.h>
  31 #ifndef __AROS__
  32 #include <machine/fpu.h>
  33 #endif
  34 #include <fenv.h>
  35
  36 const fenv_t __fe_dfl_env = {
  37         { 0xffff0000 | __INITIAL_FPUCW__,
  38           0xffff0000,
  39           0xffffffff,
  40           { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  41             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff }
  42         },
  43         __INITIAL_MXCSR__
  44 };
  45
  46 int
  47 fesetexceptflag(const fexcept_t *flagp, int excepts)
  48 {
  49         fenv_t env;
  50
  51         __fnstenv(&env.__x87);
  52         env.__x87.__status &= ~excepts;
  53         env.__x87.__status |= *flagp & excepts;
  54         __fldenv(env.__x87);
  55
  56         __stmxcsr(&env.__mxcsr);
  57         env.__mxcsr &= ~excepts;
  58         env.__mxcsr |= *flagp & excepts;
  59         __ldmxcsr(env.__mxcsr);
  60
  61         return (0);
  62 }
  63
  64 int
  65 feraiseexcept(int excepts)
  66 {
  67         fexcept_t ex = excepts;
  68
  69         fesetexceptflag(&ex, excepts);
  70         __fwait();
  71         return (0);
  72 }
  73
  74 int
  75 fegetenv(fenv_t *envp)
  76 {
  77
  78         __fnstenv(&envp->__x87);
  79         __stmxcsr(&envp->__mxcsr);
  80         /*
  81          * fnstenv masks all exceptions, so we need to restore the
  82          * control word to avoid this side effect.
  83          */
  84         __fldcw(envp->__x87.__control);
  85         return (0);
  86 }
  87
  88 int
  89 feholdexcept(fenv_t *envp)
  90 {
  91         int mxcsr;
  92
  93         __stmxcsr(&mxcsr);
  94         __fnstenv(&envp->__x87);
  95         __fnclex();
  96         envp->__mxcsr = mxcsr;
  97         mxcsr &= ~FE_ALL_EXCEPT;
  98         mxcsr |= FE_ALL_EXCEPT << _SSE_EMASK_SHIFT;
  99         __ldmxcsr(mxcsr);
 100         return (0);
 101 }
 102
 103 int
 104 feupdateenv(const fenv_t *envp)
 105 {
 106         int mxcsr, status;
 107
 108         __fnstsw(&status);
 109         __stmxcsr(&mxcsr);
 110         fesetenv(envp);
 111         feraiseexcept((mxcsr | status) & FE_ALL_EXCEPT);
 112         return (0);
 113 }
 114
 115 int
 116 __feenableexcept(int mask)
 117 {
 118         int mxcsr, control, omask;
 119
 120         mask &= FE_ALL_EXCEPT;
 121         __fnstcw(&control);
 122         __stmxcsr(&mxcsr);
 123         omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 124         control &= ~mask;
 125         __fldcw(control);
 126         mxcsr &= ~(mask << _SSE_EMASK_SHIFT);
 127         __ldmxcsr(mxcsr);
 128         return (~omask);
 129 }
 130
 131 int
 132 __fedisableexcept(int mask)
 133 {
 134         int mxcsr, control, omask;
 135
 136         mask &= FE_ALL_EXCEPT;
 137         __fnstcw(&control);
 138         __stmxcsr(&mxcsr);
 139         omask = (control | mxcsr >> _SSE_EMASK_SHIFT) & FE_ALL_EXCEPT;
 140         control |= mask;
 141         __fldcw(control);
 142         mxcsr |= mask << _SSE_EMASK_SHIFT;
 143         __ldmxcsr(mxcsr);
 144         return (~omask);
 145 }
 146
 147 __weak_reference(__feenableexcept, feenableexcept);
 148 __weak_reference(__fedisableexcept, fedisableexcept);