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7993050251
features appear to work, subject to the caveat that you tell gcc you want standard rather than recklessly fast behavior (-mieee-with-inexact -mfp-rounding-mode=d). The non-standard feature of delivering a SIGFPE when an application raises an unmasked exception does not work, presumably due to a kernel bug. This isn't so bad given that floating-point exceptions on the Alpha architecture are not precise, so making them useful in userland requires a significant amount of wizardry. Reviewed by: standards@
132 lines
3.2 KiB
C
132 lines
3.2 KiB
C
/*-
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* Copyright (c) 2004 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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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <sys/cdefs.h>
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#include <machine/sysarch.h>
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#include <fenv.h>
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const fenv_t __fe_dfl_env = 0x680e000000000000ULL;
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struct mask_args {
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fenv_t mask;
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};
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/*
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* The lower 49 bits of the FPCR are unused by the hardware, so we use
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* the lower order bits to store the kernel's idea of the FP mask as
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* described in the Alpha Architecture Manual.
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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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struct mask_args p;
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union __fpcr r;
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/*
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* The syscall acts as an implicit exception barrier, so we
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* only need to issue an excb after the mf_fpcr to ensure that
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* the read is executed before any subsequent FP ops.
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*/
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sysarch(ALPHA_GET_FPMASK, (char *)&p);
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__mf_fpcr(&r.__d);
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*envp = r.__bits | p.mask;
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__excb();
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return (0);
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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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struct mask_args p;
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union __fpcr r;
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sysarch(ALPHA_GET_FPMASK, (char *)&p);
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__mf_fpcr(&r.__d);
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*envp = r.__bits | p.mask;
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r.__bits &= ~((fenv_t)FE_ALL_EXCEPT << _FPUSW_SHIFT);
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__mt_fpcr(r.__d);
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if (p.mask & FE_ALL_EXCEPT) {
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p.mask = 0;
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sysarch(ALPHA_SET_FPMASK, &p);
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}
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__excb();
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return (0);
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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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struct mask_args p;
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union __fpcr r;
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p.mask = *envp & FE_ALL_EXCEPT;
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sysarch(ALPHA_SET_FPMASK, &p);
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r.__bits = *envp & ~FE_ALL_EXCEPT;
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__mt_fpcr(r.__d);
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__excb();
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return (0);
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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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struct mask_args p;
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union __fpcr oldr, newr;
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p.mask = *envp & FE_ALL_EXCEPT;
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sysarch(ALPHA_SET_FPMASK, &p);
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__mf_fpcr(&oldr.__d);
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newr.__bits = *envp & ~FE_ALL_EXCEPT;
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__excb();
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__mt_fpcr(newr.__d);
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feraiseexcept((oldr.__bits >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
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return (0);
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}
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int
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__fesetmask(int mask)
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{
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struct mask_args p;
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p.mask = mask;
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sysarch(ALPHA_SET_FPMASK, &p);
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return (p.mask);
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}
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int
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__fegetmask(void)
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{
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struct mask_args p;
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sysarch(ALPHA_GET_FPMASK, &p);
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return (p.mask);
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}
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__weak_reference(__fesetmask, fesetmask);
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__weak_reference(__fegetmask, fegetmask);
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