1 /* $OpenBSD: fixunssfdi.c,v 1.7 2019/11/10 22:23:28 guenther Exp $ */ 2 /*- 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This software was developed by the Computer Systems Engineering group 7 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 8 * contributed to Berkeley. 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "quad.h" 36 37 #define ONE_FOURTH ((int)1 << (INT_BITS - 2)) 38 #define ONE_HALF (ONE_FOURTH * 2.0) 39 #define ONE (ONE_FOURTH * 4.0) 40 41 /* 42 * Convert float to (unsigned) quad. We do most of our work in double, 43 * out of sheer paranoia. 44 * 45 * Not sure what to do with negative numbers---for now, anything out 46 * of range becomes UQUAD_MAX. 47 * 48 * N.B.: must use new ANSI syntax (sorry). 49 */ 50 u_quad_t 51 __fixunssfdi(float f) 52 { 53 double x, toppart; 54 union uu t; 55 56 if (f < 0) 57 return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 58 #ifdef notdef /* this falls afoul of a GCC bug */ 59 if (f >= UQUAD_MAX) 60 return (UQUAD_MAX); 61 #else /* so we wire in 2^64-1 instead */ 62 if (f >= 18446744073709551615.0) /* XXX */ 63 return (UQUAD_MAX); 64 #endif 65 x = f; 66 /* 67 * Get the upper part of the result. Note that the divide 68 * may round up; we want to avoid this if possible, so we 69 * subtract `1/2' first. 70 */ 71 toppart = (x - ONE_HALF) / ONE; 72 /* 73 * Now build a u_quad_t out of the top part. The difference 74 * between x and this is the bottom part (this may introduce 75 * a few fuzzy bits, but what the heck). With any luck this 76 * difference will be nonnegative: x should wind up in the 77 * range [0..UINT_MAX]. For paranoia, we assume [INT_MIN.. 78 * 2*UINT_MAX] instead. 79 */ 80 t.ul[H] = (unsigned int)toppart; 81 t.ul[L] = 0; 82 x -= (double)t.uq; 83 if (x < 0) { 84 t.ul[H]--; 85 x += UINT_MAX; 86 } 87 if (x > UINT_MAX) { 88 t.ul[H]++; 89 x -= UINT_MAX; 90 } 91 t.ul[L] = (u_int)x; 92 return (t.uq); 93 } 94 95 #ifdef __ARM_EABI__ 96 __strong_alias(__aeabi_f2ulz, __fixunssfdi); 97 __asm(".protected __aeabi_f2ulz"); 98 #endif 99