1 /* $NetBSD: fpsetsticky.c,v 1.2 2008/04/28 20:22:57 martin 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 __RCSID("$NetBSD: fpsetsticky.c,v 1.2 2008/04/28 20:22:57 martin Exp $"); 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include "namespace.h" 38 39 #include <sys/types.h> 40 #include <ieeefp.h> 41 #include <powerpc/fpu.h> 42 43 #define STICKYBITS (FPSCR_XX|FPSCR_ZX|FPSCR_UX|FPSCR_OX|FPSCR_VX) 44 #define INVBITS (FPSCR_VXCVI|FPSCR_VXSQRT|FPSCR_VXSOFT|FPSCR_VXVC|\ 45 FPSCR_VXIMZ|FPSCR_VXZDZ|FPSCR_VXIDI|FPSCR_VXISI|\ 46 FPSCR_VXSNAN) 47 #define STICKYSHFT 25 48 49 #ifdef __weak_alias 50 __weak_alias(fpsetsticky,_fpsetsticky) 51 #endif 52 53 fp_except 54 fpsetsticky(fp_except mask) 55 { 56 uint64_t fpscr; 57 fp_except old; 58 59 __asm volatile("mffs %0" : "=f"(fpscr)); 60 old = ((uint32_t)fpscr & STICKYBITS) >> STICKYSHFT; 61 /* 62 * FPSCR_VX (aka FP_X_INV) is not a sticky bit but a summary of the 63 * all the FPSCR_VX* sticky bits. So when FP_X_INV is cleared then 64 * clear all of those bits, likewise when it's set, set them all. 65 */ 66 if ((mask & FP_X_INV) == 0) 67 fpscr &= ~INVBITS; 68 else 69 fpscr |= INVBITS; 70 fpscr &= ~STICKYBITS; 71 fpscr |= ((uint32_t)mask << STICKYSHFT) & STICKYBITS; 72 /* 73 * Make FPSCR_FX reflect the presence of a set sticky bit (or not). 74 */ 75 if (fpscr & (STICKYBITS|INVBITS)) 76 fpscr |= FPSCR_FX; 77 else 78 fpscr &= ~FPSCR_FX; 79 /* 80 * Write back the fpscr. 81 */ 82 __asm volatile("mtfsf 0xff,%0" :: "f"(fpscr)); 83 return (old); 84 } 85