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1f0502d3 | 1 | /* |
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2 | * Copyright (c) 1986, 1993 |
3 | * The Regents of the University of California. All rights reserved. | |
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4 | * |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Computer Consoles Inc. | |
7 | * | |
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8 | * Redistribution and use in source and binary forms, with or without |
9 | * modification, are permitted provided that the following conditions | |
10 | * are met: | |
11 | * 1. Redistributions of source code must retain the above copyright | |
12 | * notice, this list of conditions and the following disclaimer. | |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in the | |
15 | * documentation and/or other materials provided with the distribution. | |
16 | * 3. All advertising materials mentioning features or use of this software | |
17 | * must display the following acknowledgement: | |
18 | * This product includes software developed by the University of | |
19 | * California, Berkeley and its contributors. | |
20 | * 4. Neither the name of the University nor the names of its contributors | |
21 | * may be used to endorse or promote products derived from this software | |
22 | * without specific prior written permission. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
34 | * SUCH DAMAGE. | |
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35 | */ |
36 | ||
37 | #if defined(SYSLIBC_SCCS) && !defined(lint) | |
ad787160 | 38 | .asciz "@(#)cvtdl.s 8.1 (Berkeley) 6/4/93" |
1f0502d3 | 39 | #endif /* SYSLIBC_SCCS and not lint */ |
d09f4772 SL |
40 | |
41 | #include <tahoemath/fp.h> | |
42 | #include "DEFS.h" | |
43 | ||
44 | XENTRY(cvtdu, R2|R3|R4|R5) | |
45 | jbr 1f | |
46 | ||
47 | XENTRY(cvtdl, R2|R3|R4|R5) | |
48 | # | |
49 | #Some initializations: | |
50 | # | |
51 | 1: | |
52 | movl 4(fp),r0 # fetch operand. | |
53 | movl 8(fp),r1 | |
54 | clrl r3 # r3 - negative flag. | |
55 | # | |
56 | #get exponent | |
57 | # | |
58 | andl3 $EXPMASK,r0,r2 # r2 will hold the exponent. | |
59 | jeql is_reserved # check for reserved operand. | |
60 | cmpl $ONE_EXP,r2 # if exponent is less then 1,return zero. | |
61 | jgtr retzero | |
62 | andl2 $0!EXPSIGN,r2 # turn off biased exponent sign | |
63 | shrl $EXPSHIFT,r2,r2 | |
64 | # | |
65 | #get fraction | |
66 | # | |
67 | bbc $31,r0,positive # if negative remember it. | |
68 | incl r3 | |
69 | positive: | |
70 | # clear the non fraction parts. | |
71 | andl2 $(0!(EXPMASK | SIGNBIT)),r0 | |
72 | # add the hidden bit. | |
73 | orl2 $(0!CLEARHID),r0 | |
74 | subl2 $24,r2 # compute the shift. | |
75 | jgtr shift_left | |
76 | mnegl r2,r2 | |
77 | shrl r2,r0,r0 # shift right. | |
78 | jmp shifted | |
79 | shift_left: | |
80 | cmpl r2,$7 | |
81 | jgtr overflow | |
82 | go_on: shlq r2,r0,r0 # shift right. | |
83 | shifted: | |
84 | bbc $0,r3,done # check for negative | |
85 | mnegl r0,r0 | |
86 | done: | |
87 | ret | |
88 | ||
89 | retzero: | |
90 | clrl r0 | |
91 | ret | |
92 | overflow: | |
93 | callf $4,fpover | |
94 | jmp go_on | |
95 | ||
96 | is_reserved: | |
97 | bbc $31,r0,retzero | |
98 | ||
99 | callf $4,fpresop | |
100 | ret |