1 /* $NetBSD: fpsetsticky.c,v 1.6 2004/04/04 19:54:05 matt Exp $ */ 2 3 /* 4 * Copyright (c) 1999 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Dan Winship. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 41 #include "namespace.h" 42 43 #include <sys/types.h> 44 #include <ieeefp.h> 45 #include <powerpc/fpu.h> 46 47 #define STICKYBITS (FPSCR_XX|FPSCR_ZX|FPSCR_UX|FPSCR_OX|FPSCR_VX) 48 #define INVBITS (FPSCR_VXCVI|FPSCR_VXSQRT|FPSCR_VXSOFT|FPSCR_VXVC|\ 49 FPSCR_VXIMZ|FPSCR_VXZDZ|FPSCR_VXIDI|FPSCR_VXISI|\ 50 FPSCR_VXSNAN) 51 #define STICKYSHFT 25 52 53 #ifdef __weak_alias 54 __weak_alias(fpsetsticky,_fpsetsticky) 55 #endif 56 57 fp_except 58 fpsetsticky(fp_except mask) 59 { 60 uint64_t fpscr; 61 fp_except old; 62 63 __asm__ __volatile("mffs %0" : "=f"(fpscr)); 64 old = ((uint32_t)fpscr & STICKYBITS) >> STICKYSHFT; 65 /* 66 * FPSCR_VX (aka FP_X_INV) is not a sticky bit but a summary of the 67 * all the FPSCR_VX* sticky bits. So when FP_X_INV is cleared then 68 * clear all of those bits, likewise when it's set, set them all. 69 */ 70 if ((mask & FP_X_INV) == 0) 71 fpscr &= ~INVBITS; 72 else 73 fpscr |= INVBITS; 74 fpscr &= ~STICKYBITS; 75 fpscr |= ((uint32_t)mask << STICKYSHFT) & STICKYBITS; 76 /* 77 * Make FPSCR_FX reflect the presence of a set sticky bit (or not). 78 */ 79 if (fpscr & (STICKYBITS|INVBITS)) 80 fpscr |= FPSCR_FX; 81 else 82 fpscr &= ~FPSCR_FX; 83 /* 84 * Write back the fpscr. 85 */ 86 __asm__ __volatile("mtfsf 0xff,%0" :: "f"(fpscr)); 87 return (old); 88 } 89