351 lines
7.9 KiB
C
351 lines
7.9 KiB
C
/* $NetBSD: fenv.c,v 1.2 2017/03/22 23:11:09 chs Exp $ */
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/*-
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* Copyright (c) 2004-2005 David Schultz <das@FreeBSD.ORG>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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*/
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: fenv.c,v 1.2 2017/03/22 23:11:09 chs Exp $");
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#include <assert.h>
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#include <fenv.h>
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#define _DIAGASSERT(x) assert(x)
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#ifdef __weak_alias
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__weak_alias(feclearexcept,_feclearexcept)
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__weak_alias(fedisableexcept,_fedisableexcept)
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__weak_alias(feenableexcept,_feenableexcept)
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__weak_alias(fegetenv,_fegetenv)
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__weak_alias(fegetexcept,_fegetexcept)
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__weak_alias(fegetexceptflag,_fegetexceptflag)
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__weak_alias(fegetround,_fegetround)
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__weak_alias(feholdexcept,_feholdexcept)
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__weak_alias(feraiseexcept,_feraiseexcept)
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__weak_alias(fesetenv,_fesetenv)
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__weak_alias(fesetexceptflag,_fesetexceptflag)
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__weak_alias(fesetround,_fesetround)
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__weak_alias(fetestexcept,_fetestexcept)
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__weak_alias(feupdateenv,_feupdateenv)
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#endif
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/* Load floating-point state register (32bits) */
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#define __ldfsr(__r) __asm__ __volatile__ \
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("ld %0, %%fsr" : : "m" (__r))
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/* Save floating-point state register (32bits) */
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#define __stfsr(__r) __asm__ __volatile__ \
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("st %%fsr, %0" : "=m" (*(__r)))
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/*
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* The feclearexcept() function clears the supported floating-point exceptions
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* represented by `excepts'.
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*/
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int
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feclearexcept(int excepts)
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{
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fexcept_t r;
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int ex;
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_DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0);
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ex = excepts & FE_ALL_EXCEPT;
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__stfsr(&r);
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r &= ~ex;
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__ldfsr(r);
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/* Success */
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return 0;
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}
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/*
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* The fegetexceptflag() function stores an implementation-defined
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* representation of the states of the floating-point status flags indicated
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* by the argument excepts in the object pointed to by the argument flagp.
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*/
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int
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fegetexceptflag(fexcept_t *flagp, int excepts)
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{
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fexcept_t r;
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int ex;
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_DIAGASSERT(flagp != NULL);
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_DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0);
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ex = excepts & FE_ALL_EXCEPT;
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__stfsr(&r);
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*flagp = r & ex;
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/* Success */
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return 0;
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}
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/*
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* This function sets the floating-point status flags indicated by the argument
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* `excepts' to the states stored in the object pointed to by `flagp'. It does
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* NOT raise any floating-point exceptions, but only sets the state of the flags.
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*/
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int
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fesetexceptflag(const fexcept_t *flagp, int excepts)
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{
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fexcept_t r;
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int ex;
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_DIAGASSERT(flagp != NULL);
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_DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0);
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ex = excepts & FE_ALL_EXCEPT;
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__stfsr(&r);
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r &= ~ex;
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r |= *flagp & ex;
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__ldfsr(r);
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/* Success */
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return 0;
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}
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/*
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* The feraiseexcept() function raises the supported floating-point exceptions
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* represented by the argument `excepts'.
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*
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* The order in which these floating-point exceptions are raised is unspecified
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* (by the standard).
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*/
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int
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feraiseexcept(int excepts)
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{
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volatile double d;
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int ex;
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_DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0);
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ex = excepts & FE_ALL_EXCEPT;
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/*
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* With a compiler that supports the FENV_ACCESS pragma properly, simple
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* expressions like '0.0 / 0.0' should be sufficient to generate traps.
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* Unfortunately, we need to bring a volatile variable into the equation
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* to prevent incorrect optimizations.
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*/
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if (ex & FE_INVALID) {
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d = 0.0;
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d = 0.0 / d;
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}
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if (ex & FE_DIVBYZERO) {
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d = 0.0;
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d = 1.0 / d;
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}
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if (ex & FE_OVERFLOW) {
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d = 0x1.ffp1023;
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d *= 2.0;
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}
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if (ex & FE_UNDERFLOW) {
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d = 0x1p-1022;
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d /= 0x1p1023;
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}
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if (ex & FE_INEXACT) {
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d = 0x1p-1022;
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d += 1.0;
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}
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/* Success */
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return 0;
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}
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/*
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* The fetestexcept() function determines which of a specified subset of the
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* floating-point exception flags are currently set. The `excepts' argument
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* specifies the floating-point status flags to be queried.
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*/
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int
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fetestexcept(int excepts)
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{
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fexcept_t r;
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_DIAGASSERT((excepts & ~FE_ALL_EXCEPT) == 0);
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__stfsr(&r);
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return r & (excepts & FE_ALL_EXCEPT);
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}
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/*
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* The fegetround() function gets the current rounding direction.
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*/
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int
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fegetround(void)
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{
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fenv_t r;
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__stfsr(&r);
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return (r >> _ROUND_SHIFT) & _ROUND_MASK;
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}
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/*
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* The fesetround() function establishes the rounding direction represented by
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* its argument `round'. If the argument is not equal to the value of a rounding
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* direction macro, the rounding direction is not changed.
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*/
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int
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fesetround(int round)
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{
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fenv_t r;
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_DIAGASSERT((round & ~_ROUND_MASK) == 0);
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if (round & ~_ROUND_MASK)
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return -1;
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__stfsr(&r);
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r &= ~(_ROUND_MASK << _ROUND_SHIFT);
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r |= round << _ROUND_SHIFT;
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__ldfsr(r);
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/* Success */
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return 0;
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}
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/*
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* The fegetenv() function attempts to store the current floating-point
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* environment in the object pointed to by envp.
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*/
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int
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fegetenv(fenv_t *envp)
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{
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_DIAGASSERT(envp != NULL);
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__stfsr(envp);
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/* Success */
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return 0;
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}
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/*
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* The feholdexcept() function saves the current floating-point environment
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* in the object pointed to by envp, clears the floating-point status flags, and
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* then installs a non-stop (continue on floating-point exceptions) mode, if
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* available, for all floating-point exceptions.
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*/
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int
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feholdexcept(fenv_t *envp)
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{
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fenv_t r;
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_DIAGASSERT(envp != NULL);
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__stfsr(&r);
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*envp = r;
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r &= ~(FE_ALL_EXCEPT | _ENABLE_MASK);
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__ldfsr(r);
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/* Success */
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return 0;
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}
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/*
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* The fesetenv() function attempts to establish the floating-point environment
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* represented by the object pointed to by envp. The argument `envp' points
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* to an object set by a call to fegetenv() or feholdexcept(), or equal a
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* floating-point environment macro. The fesetenv() function does not raise
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* floating-point exceptions, but only installs the state of the floating-point
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* status flags represented through its argument.
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*/
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int
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fesetenv(const fenv_t *envp)
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{
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_DIAGASSERT(envp != NULL);
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__ldfsr(*envp);
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/* Success */
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return 0;
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}
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/*
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* The feupdateenv() function saves the currently raised floating-point
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* exceptions in its automatic storage, installs the floating-point environment
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* represented by the object pointed to by `envp', and then raises the saved
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* floating-point exceptions. The argument `envp' shall point to an object set
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* by a call to feholdexcept() or fegetenv(), or equal a floating-point
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* environment macro.
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*/
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int
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feupdateenv(const fenv_t *envp)
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{
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fexcept_t r;
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_DIAGASSERT(envp != NULL);
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__stfsr(&r);
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__ldfsr(*envp);
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_DIAGASSERT((r & ~FE_ALL_EXCEPT) == 0);
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feraiseexcept(r & FE_ALL_EXCEPT);
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/* Success */
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return 0;
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}
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/*
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* The following functions are extentions to the standard
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*/
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int
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feenableexcept(int mask)
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{
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fenv_t old_r, new_r;
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__stfsr(&old_r);
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new_r = old_r | ((mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
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__ldfsr(new_r);
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return (old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT;
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}
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int
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fedisableexcept(int mask)
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{
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fenv_t old_r, new_r;
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__stfsr(&old_r);
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new_r = old_r & ~((mask & FE_ALL_EXCEPT) << _FPUSW_SHIFT);
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__ldfsr(new_r);
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return (old_r >> _FPUSW_SHIFT) & FE_ALL_EXCEPT;
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}
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int
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fegetexcept(void)
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{
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fenv_t r;
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__stfsr(&r);
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return (r & _ENABLE_MASK) >> _FPUSW_SHIFT;
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}
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