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fpsetsticky.c revision 1.2.8.2 
      1  1.2.8.2  martin /*	$NetBSD: fpsetsticky.c,v 1.2.8.2 2008/04/28 20:22:58 martin Exp $	*/
      2  1.2.8.2  martin 
      3  1.2.8.2  martin /*
      4  1.2.8.2  martin  * Copyright (c) 1999 The NetBSD Foundation, Inc.
      5  1.2.8.2  martin  * All rights reserved.
      6  1.2.8.2  martin  *
      7  1.2.8.2  martin  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2.8.2  martin  * by Dan Winship.
      9  1.2.8.2  martin  *
     10  1.2.8.2  martin  * Redistribution and use in source and binary forms, with or without
     11  1.2.8.2  martin  * modification, are permitted provided that the following conditions
     12  1.2.8.2  martin  * are met:
     13  1.2.8.2  martin  * 1. Redistributions of source code must retain the above copyright
     14  1.2.8.2  martin  *    notice, this list of conditions and the following disclaimer.
     15  1.2.8.2  martin  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2.8.2  martin  *    notice, this list of conditions and the following disclaimer in the
     17  1.2.8.2  martin  *    documentation and/or other materials provided with the distribution.
     18  1.2.8.2  martin  *
     19  1.2.8.2  martin  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2.8.2  martin  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2.8.2  martin  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2.8.2  martin  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2.8.2  martin  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2.8.2  martin  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2.8.2  martin  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2.8.2  martin  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2.8.2  martin  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2.8.2  martin  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2.8.2  martin  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2.8.2  martin  */
     31  1.2.8.2  martin 
     32  1.2.8.2  martin #include <sys/cdefs.h>
     33  1.2.8.2  martin #if defined(LIBC_SCCS) && !defined(lint)
     34  1.2.8.2  martin __RCSID("$NetBSD: fpsetsticky.c,v 1.2.8.2 2008/04/28 20:22:58 martin Exp $");
     35  1.2.8.2  martin #endif /* LIBC_SCCS and not lint */
     36  1.2.8.2  martin 
     37  1.2.8.2  martin #include "namespace.h"
     38  1.2.8.2  martin 
     39  1.2.8.2  martin #include <sys/types.h>
     40  1.2.8.2  martin #include <ieeefp.h>
     41  1.2.8.2  martin #include <powerpc/fpu.h>
     42  1.2.8.2  martin 
     43  1.2.8.2  martin #define	STICKYBITS	(FPSCR_XX|FPSCR_ZX|FPSCR_UX|FPSCR_OX|FPSCR_VX)
     44  1.2.8.2  martin #define	INVBITS		(FPSCR_VXCVI|FPSCR_VXSQRT|FPSCR_VXSOFT|FPSCR_VXVC|\
     45  1.2.8.2  martin 			 FPSCR_VXIMZ|FPSCR_VXZDZ|FPSCR_VXIDI|FPSCR_VXISI|\
     46  1.2.8.2  martin 			 FPSCR_VXSNAN)
     47  1.2.8.2  martin #define	STICKYSHFT	25
     48  1.2.8.2  martin 
     49  1.2.8.2  martin #ifdef __weak_alias
     50  1.2.8.2  martin __weak_alias(fpsetsticky,_fpsetsticky)
     51  1.2.8.2  martin #endif
     52  1.2.8.2  martin 
     53  1.2.8.2  martin fp_except
     54  1.2.8.2  martin fpsetsticky(fp_except mask)
     55  1.2.8.2  martin {
     56  1.2.8.2  martin 	uint64_t fpscr;
     57  1.2.8.2  martin 	fp_except old;
     58  1.2.8.2  martin 
     59  1.2.8.2  martin 	__asm volatile("mffs %0" : "=f"(fpscr));
     60  1.2.8.2  martin 	old = ((uint32_t)fpscr & STICKYBITS) >> STICKYSHFT;
     61  1.2.8.2  martin 	/*
     62  1.2.8.2  martin 	 * FPSCR_VX (aka FP_X_INV) is not a sticky bit but a summary of the
     63  1.2.8.2  martin 	 * all the FPSCR_VX* sticky bits.  So when FP_X_INV is cleared then
     64  1.2.8.2  martin 	 * clear all of those bits, likewise when it's set, set them all.
     65  1.2.8.2  martin 	 */
     66  1.2.8.2  martin 	if ((mask & FP_X_INV) == 0)
     67  1.2.8.2  martin 		fpscr &= ~INVBITS;
     68  1.2.8.2  martin 	else
     69  1.2.8.2  martin 		fpscr |= INVBITS;
     70  1.2.8.2  martin 	fpscr &= ~STICKYBITS;
     71  1.2.8.2  martin 	fpscr |= ((uint32_t)mask << STICKYSHFT) & STICKYBITS;
     72  1.2.8.2  martin 	/*
     73  1.2.8.2  martin 	 * Make FPSCR_FX reflect the presence of a set sticky bit (or not).
     74  1.2.8.2  martin 	 */
     75  1.2.8.2  martin 	if (fpscr & (STICKYBITS|INVBITS))
     76  1.2.8.2  martin 		fpscr |= FPSCR_FX;
     77  1.2.8.2  martin 	else
     78  1.2.8.2  martin 		fpscr &= ~FPSCR_FX;
     79  1.2.8.2  martin 	/*
     80  1.2.8.2  martin 	 * Write back the fpscr.
     81  1.2.8.2  martin 	 */
     82  1.2.8.2  martin 	__asm volatile("mtfsf 0xff,%0" :: "f"(fpscr));
     83  1.2.8.2  martin 	return (old);
     84  1.2.8.2  martin }
     85