154746Storek /*- 2*61160Sbostic * Copyright (c) 1992, 1993 3*61160Sbostic * The Regents of the University of California. All rights reserved. 454746Storek * 554746Storek * This software was developed by the Computer Systems Engineering group 654746Storek * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 754746Storek * contributed to Berkeley. 854746Storek * 954746Storek * %sccs.include.redist.c% 1054746Storek */ 1154746Storek 1254746Storek #if defined(LIBC_SCCS) && !defined(lint) 13*61160Sbostic static char sccsid[] = "@(#)fixunssfdi.c 8.1 (Berkeley) 06/04/93"; 1454746Storek #endif /* LIBC_SCCS and not lint */ 1554746Storek 1654746Storek #include "quad.h" 1754746Storek 1854746Storek #define ONE_FOURTH (1 << (LONG_BITS - 2)) 1954746Storek #define ONE_HALF (ONE_FOURTH * 2.0) 2054746Storek #define ONE (ONE_FOURTH * 4.0) 2154746Storek 2254746Storek /* 2354746Storek * Convert float to (unsigned) quad. We do most of our work in double, 2454746Storek * out of sheer paranoia. 2554746Storek * 2654746Storek * Not sure what to do with negative numbers---for now, anything out 2754746Storek * of range becomes UQUAD_MAX. 2854746Storek * 2954746Storek * N.B.: must use new ANSI syntax (sorry). 3054746Storek */ 3154746Storek u_quad_t __fixunssfdi(float f)3254746Storek__fixunssfdi(float f) 3354746Storek { 3454746Storek double x, toppart; 3554746Storek union uu t; 3654746Storek 3754746Storek if (f < 0) 3854746Storek return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ 3955180Storek #ifdef notdef /* this falls afoul of a GCC bug */ 4054746Storek if (f >= UQUAD_MAX) 4154746Storek return (UQUAD_MAX); 4255180Storek #else /* so we wire in 2^64-1 instead */ 4355180Storek if (f >= 18446744073709551615.0) 4455180Storek return (UQUAD_MAX); 4555180Storek #endif 4654746Storek x = f; 4754746Storek /* 4854746Storek * Get the upper part of the result. Note that the divide 4954746Storek * may round up; we want to avoid this if possible, so we 5054746Storek * subtract `1/2' first. 5154746Storek */ 5254746Storek toppart = (x - ONE_HALF) / ONE; 5354746Storek /* 5454746Storek * Now build a u_quad_t out of the top part. The difference 5554746Storek * between x and this is the bottom part (this may introduce 5654746Storek * a few fuzzy bits, but what the heck). With any luck this 5754746Storek * difference will be nonnegative: x should wind up in the 5854746Storek * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. 5954746Storek * 2*ULONG_MAX] instead. 6054746Storek */ 6154746Storek t.ul[H] = (unsigned long)toppart; 6254746Storek t.ul[L] = 0; 6354746Storek x -= (double)t.uq; 6454746Storek if (x < 0) { 6554746Storek t.ul[H]--; 6654746Storek x += ULONG_MAX; 6754746Storek } 6854746Storek if (x > ULONG_MAX) { 6954746Storek t.ul[H]++; 7054746Storek x -= ULONG_MAX; 7154746Storek } 7254746Storek t.ul[L] = (u_long)x; 7354746Storek return (t.uq); 7454746Storek } 75