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      1  1.10     matt /*	$NetBSD: fpsetround.c,v 1.10 2011/07/10 21:18:47 matt Exp $	*/
      2   1.1     danw 
      3   1.1     danw /*
      4   1.1     danw  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5   1.1     danw  * All rights reserved.
      6   1.1     danw  *
      7   1.1     danw  * This code is derived from software contributed to The NetBSD Foundation
      8   1.1     danw  * by Dan Winship.
      9   1.1     danw  *
     10   1.1     danw  * Redistribution and use in source and binary forms, with or without
     11   1.1     danw  * modification, are permitted provided that the following conditions
     12   1.1     danw  * are met:
     13   1.1     danw  * 1. Redistributions of source code must retain the above copyright
     14   1.1     danw  *    notice, this list of conditions and the following disclaimer.
     15   1.1     danw  * 2. Redistributions in binary form must reproduce the above copyright
     16   1.1     danw  *    notice, this list of conditions and the following disclaimer in the
     17   1.1     danw  *    documentation and/or other materials provided with the distribution.
     18   1.1     danw  *
     19   1.1     danw  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20   1.1     danw  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21   1.1     danw  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22   1.1     danw  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23   1.1     danw  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24   1.1     danw  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25   1.1     danw  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26   1.1     danw  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27   1.1     danw  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28   1.1     danw  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29   1.1     danw  * POSSIBILITY OF SUCH DAMAGE.
     30   1.1     danw  */
     31   1.1     danw 
     32   1.3  thorpej #include <sys/cdefs.h>
     33   1.6    lukem #if defined(LIBC_SCCS) && !defined(lint)
     34  1.10     matt __RCSID("$NetBSD: fpsetround.c,v 1.10 2011/07/10 21:18:47 matt Exp $");
     35   1.6    lukem #endif /* LIBC_SCCS and not lint */
     36   1.3  thorpej 
     37   1.3  thorpej #include "namespace.h"
     38   1.3  thorpej 
     39   1.1     danw #include <sys/types.h>
     40   1.1     danw #include <ieeefp.h>
     41   1.4     matt #include <powerpc/fpu.h>
     42   1.3  thorpej 
     43   1.3  thorpej #ifdef __weak_alias
     44   1.3  thorpej __weak_alias(fpsetround,_fpsetround)
     45   1.3  thorpej #endif
     46   1.1     danw 
     47   1.4     matt #define	ROUNDBITS	FPSCR_RN
     48   1.4     matt 
     49   1.1     danw fp_rnd
     50   1.4     matt fpsetround(fp_rnd rnd_dir)
     51   1.1     danw {
     52  1.10     matt 	union {
     53  1.10     matt 		double u_d;
     54  1.10     matt 		uint64_t u_fpscr;
     55  1.10     matt 	} ud;
     56   1.1     danw 	fp_rnd old;
     57   1.1     danw 
     58  1.10     matt 	__asm volatile("mffs %0" : "=f"(ud.u_d));
     59  1.10     matt 	old = (uint32_t)ud.u_fpscr & ROUNDBITS;
     60  1.10     matt 	ud.u_fpscr &= ~ROUNDBITS;
     61  1.10     matt 	ud.u_fpscr |= rnd_dir & ROUNDBITS;
     62  1.10     matt 	__asm volatile("mtfsf 0xff,%0" :: "f"(ud.u_d));
     63   1.1     danw 	return (old);
     64   1.1     danw }
     65