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| Rev | Author | Line No. | Line |
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| 2 | pj | 1 | /*- |
| 2 | * Copyright (c) 1992, 1993 |
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| 3 | * The Regents of the University of California. All rights reserved. |
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| 4 | * |
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| 5 | * This software was developed by the Computer Systems Engineering group |
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| 6 | * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and |
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| 7 | * contributed to Berkeley. |
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| 8 | * |
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| 9 | * Redistribution and use in source and binary forms, with or without |
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| 10 | * modification, are permitted provided that the following conditions |
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| 11 | * are met: |
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| 12 | * 1. Redistributions of source code must retain the above copyright |
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| 13 | * notice, this list of conditions and the following disclaimer. |
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| 14 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 15 | * notice, this list of conditions and the following disclaimer in the |
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| 16 | * documentation and/or other materials provided with the distribution. |
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| 17 | * 3. All advertising materials mentioning features or use of this software |
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| 18 | * must display the following acknowledgement: |
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| 19 | * This product includes software developed by the University of |
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| 20 | * California, Berkeley and its contributors. |
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| 21 | * 4. Neither the name of the University nor the names of its contributors |
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| 22 | * may be used to endorse or promote products derived from this software |
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| 23 | * without specific prior written permission. |
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| 24 | * |
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| 25 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 26 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 27 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 28 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 29 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 30 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 31 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 32 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 33 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 34 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 35 | * SUCH DAMAGE. |
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| 36 | */ |
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| 37 | |||
| 38 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 39 | static char sccsid[] = "@(#)fixunssfdi.c 8.1 (Berkeley) 6/4/93"; |
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| 40 | #endif /* LIBC_SCCS and not lint */ |
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| 41 | |||
| 42 | #include "quad.h" |
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| 43 | |||
| 44 | #define ONE_FOURTH (1 << (LONG_BITS - 2)) |
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| 45 | #define ONE_HALF (ONE_FOURTH * 2.0) |
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| 46 | #define ONE (ONE_FOURTH * 4.0) |
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| 47 | |||
| 48 | /* |
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| 49 | * Convert float to (unsigned) quad. We do most of our work in double, |
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| 50 | * out of sheer paranoia. |
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| 51 | * |
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| 52 | * Not sure what to do with negative numbers---for now, anything out |
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| 53 | * of range becomes UQUAD_MAX. |
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| 54 | * |
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| 55 | * N.B.: must use new ANSI syntax (sorry). |
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| 56 | */ |
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| 57 | u_quad_t |
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| 58 | __fixunssfdi(float f) |
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| 59 | { |
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| 60 | double x, toppart; |
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| 61 | union uu t; |
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| 62 | |||
| 63 | if (f < 0) |
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| 64 | return (UQUAD_MAX); /* ??? should be 0? ERANGE??? */ |
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| 65 | #ifdef notdef /* this falls afoul of a GCC bug */ |
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| 66 | if (f >= UQUAD_MAX) |
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| 67 | return (UQUAD_MAX); |
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| 68 | #else /* so we wire in 2^64-1 instead */ |
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| 69 | if (f >= 18446744073709551615.0) |
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| 70 | return (UQUAD_MAX); |
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| 71 | #endif |
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| 72 | x = f; |
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| 73 | /* |
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| 74 | * Get the upper part of the result. Note that the divide |
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| 75 | * may round up; we want to avoid this if possible, so we |
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| 76 | * subtract `1/2' first. |
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| 77 | */ |
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| 78 | toppart = (x - ONE_HALF) / ONE; |
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| 79 | /* |
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| 80 | * Now build a u_quad_t out of the top part. The difference |
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| 81 | * between x and this is the bottom part (this may introduce |
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| 82 | * a few fuzzy bits, but what the heck). With any luck this |
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| 83 | * difference will be nonnegative: x should wind up in the |
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| 84 | * range [0..ULONG_MAX]. For paranoia, we assume [LONG_MIN.. |
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| 85 | * 2*ULONG_MAX] instead. |
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| 86 | */ |
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| 87 | t.ul[H] = (unsigned long)toppart; |
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| 88 | t.ul[L] = 0; |
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| 89 | x -= (double)t.uq; |
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| 90 | if (x < 0) { |
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| 91 | t.ul[H]--; |
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| 92 | x += ULONG_MAX; |
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| 93 | } |
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| 94 | if (x > ULONG_MAX) { |
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| 95 | t.ul[H]++; |
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| 96 | x -= ULONG_MAX; |
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| 97 | } |
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| 98 | t.ul[L] = (u_long)x; |
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| 99 | return (t.uq); |
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| 100 | } |