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fenv.c revision 1.1 
      1 /*	$NetBSD: fenv.c,v 1.1 2016/08/23 10:00:15 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2004-2005 David Schultz <das (at) FreeBSD.ORG>
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  *
     28  * $FreeBSD: src/lib/msun/alpha/fenv.c,v 1.2 2005/03/16 19:03:44 das Exp $
     29  */
     30 #include <sys/cdefs.h>
     31 __RCSID("$NetBSD: fenv.c,v 1.1 2016/08/23 10:00:15 christos Exp $");
     32 
     33 #ifdef __weak_alias
     34 #define feenableexcept _feenableexcept
     35 #define fedisableexcept _fedisableexcept
     36 #define fegetexcept _fegetexcept
     37 #endif
     38 #include <machine/sysarch.h>
     39 #include <fenv.h>
     40 
     41 const fenv_t __fe_dfl_env = 0x680e000000000000ULL;
     42 
     43 /*
     44  * The lower 49 bits of the FPCR are unused by the hardware, so we use
     45  * the lower order bits to store the kernel's idea of the FP mask as
     46  * described in the Alpha Architecture Manual.
     47  */
     48 int
     49 fegetenv(fenv_t *envp)
     50 {
     51 	struct alpha_fp_except_args p;
     52 	union __fpcr r;
     53 
     54 	/*
     55 	 * The syscall acts as an implicit exception barrier, so we
     56 	 * only need to issue an excb after the mf_fpcr to ensure that
     57 	 * the read is executed before any subsequent FP ops.
     58 	 */
     59 	sysarch(ALPHA_FPGETMASK, (char *)&p);
     60 	__mf_fpcr(&r.__d);
     61 	*envp = r.__bits | p.mask;
     62 	__excb();
     63 	return 0;
     64 }
     65 
     66 int
     67 feholdexcept(fenv_t *envp)
     68 {
     69 	struct alpha_fp_except_args p;
     70 	union __fpcr r;
     71 
     72 	sysarch(ALPHA_FPGETMASK, (char *)&p);
     73 	__mf_fpcr(&r.__d);
     74 	*envp = r.__bits | p.mask;
     75 	r.__bits &= ~((fenv_t)FE_ALL_EXCEPT << _FPUSW_SHIFT);
     76 	__mt_fpcr(r.__d);
     77 	if (p.mask & FE_ALL_EXCEPT) {
     78 		p.mask = 0;
     79 		sysarch(ALPHA_FPSETMASK, &p);
     80 	}
     81 	__excb();
     82 	return 0;
     83 }
     84 
     85 int
     86 fesetenv(const fenv_t *envp)
     87 {
     88 	struct alpha_fp_except_args p;
     89 	union __fpcr r;
     90 
     91 	p.mask = *envp & FE_ALL_EXCEPT;
     92 	sysarch(ALPHA_FPSETMASK, &p);
     93 	r.__bits = *envp & ~FE_ALL_EXCEPT;
     94 	__mt_fpcr(r.__d);
     95 	__excb();
     96 	return 0;
     97 }
     98 
     99 int
    100 feupdateenv(const fenv_t *envp)
    101 {
    102 	struct alpha_fp_except_args p;
    103 	union __fpcr oldr, newr;
    104 
    105 	p.mask = *envp & FE_ALL_EXCEPT;
    106 	sysarch(ALPHA_FPSETMASK, &p);
    107 	__mf_fpcr(&oldr.__d);
    108 	newr.__bits = *envp & ~FE_ALL_EXCEPT;
    109 	__excb();
    110 	__mt_fpcr(newr.__d);
    111 	feraiseexcept((oldr.__bits >> _FPUSW_SHIFT) & FE_ALL_EXCEPT);
    112 	return 0;
    113 }
    114 
    115 #ifdef __weak_alias
    116 __weak_alias(feenableexcept, _feenableexcept);
    117 __weak_alias(fedisableexcept, _fedisableexcept);
    118 __weak_alias(fegetexcept, _fegetexcept);
    119 #endif
    120 
    121 int
    122 feenableexcept(int mask)
    123 {
    124 	struct alpha_fp_except_args p;
    125 
    126 	sysarch(ALPHA_FPGETMASK, &p);
    127 	p.mask |= (mask & FE_ALL_EXCEPT);
    128 	sysarch(ALPHA_FPSETMASK, &p);
    129 	return p.mask;
    130 }
    131 
    132 int
    133 fedisableexcept(int mask)
    134 {
    135 	struct alpha_fp_except_args p;
    136 
    137 	sysarch(ALPHA_FPGETMASK, &p);
    138 	p.mask &= ~(mask & FE_ALL_EXCEPT);
    139 	sysarch(ALPHA_FPSETMASK, &p);
    140 	return p.mask;
    141 }
    142 
    143 int
    144 fegetexcept(void)
    145 {
    146 	struct alpha_fp_except_args p;
    147 
    148 	sysarch(ALPHA_FPGETMASK, &p);
    149 	return p.mask;
    150 }
    151