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1 | /*- |
2 | * Copyright (c) 1985 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * This code is derived from software contributed to Berkeley by | |
6 | * Computer Consoles Inc. | |
7 | * | |
af359dea C |
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. | |
7c27088c | 23 | * |
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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. | |
35 | * | |
36 | * @(#)Kdivd.s 7.1 (Berkeley) 12/6/90 | |
7c27088c | 37 | */ |
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39 | #include "../math/fp.h" |
40 | #include "../math/Kfp.h" | |
9d1834ba | 41 | #include "../tahoe/SYS.h" |
b3162c13 | 42 | |
2b252132 | 43 | #define HIDDEN 23 # here we count from 0 not from 1 as in fp.h |
b3162c13 SL |
44 | |
45 | .text | |
2b252132 | 46 | ENTRY(Kdivd, R9|R8|R7|R6|R5|R4|R3|R2) |
b3162c13 SL |
47 | clrl r3 # r3 - sign: 0 for positive,1 for negative. |
48 | movl 4(fp),r0 | |
49 | jgeq 1f | |
50 | movl $1,r3 | |
51 | 1: movl 12(fp),r2 | |
52 | jgeq 2f | |
53 | bbc $0,r3,1f # seconed operand is negative. | |
54 | clrl r3 # if first was negative, make result positive. | |
55 | jmp 2f | |
56 | 1: movl $1,r3 # if first was positive, make result negative. | |
57 | 2: andl2 $EXPMASK,r0 # compute first 'pure'exponent. | |
58 | jeql retz | |
59 | shrl $EXPSHIFT,r0,r0 | |
60 | subl2 $BIAS,r0 | |
61 | andl2 $EXPMASK,r2 # compute seconed 'pure'exponent. | |
62 | jeql retz2 | |
63 | shrl $EXPSHIFT,r2,r2 | |
64 | subl2 $BIAS,r2 | |
65 | subl3 r2,r0,r2 # subtruct the exponents. | |
66 | addl2 $BIAS,r2 | |
67 | jleq underf | |
68 | # normalization can make the exp. smaller. | |
69 | # | |
70 | # We have the sign in r3,the exponent in r2,now is the time to | |
71 | # perform the division... | |
72 | # | |
73 | # fetch dividend. (r4,r5) | |
74 | andl3 $(0!(EXPMASK | SIGNBIT)),4(fp),r4 | |
75 | orl2 $(0!CLEARHID),r4 | |
76 | movl 8(fp),r5 | |
77 | ||
78 | # fetch divisor : (r6,r7) | |
79 | andl3 $(0!(EXPMASK | SIGNBIT)),12(fp),r6 | |
80 | orl2 $(0!CLEARHID),r6 | |
81 | movl 16(fp),r7 | |
82 | ||
83 | movl $0,r0 # init r0,r1 to be zeros | |
84 | movl $0,r1 | |
85 | movl $(0!CLEARHID),r8# r8 first bit to set (if). | |
86 | shll $1,r8,r8 # to have one more bit,because we might | |
87 | # have to shift left to normelize. | |
88 | movl $0,r9 | |
89 | ||
90 | 2: | |
91 | subl2 r7,r5 | |
92 | sbwc r6,r4 | |
93 | jgeq 1f | |
94 | addl2 r7,r5 | |
95 | adwc r6,r4 | |
96 | shlq $1,r4,r4 | |
97 | shrq $1,r8,r8 | |
98 | jeql over | |
99 | jmp 2b | |
100 | 1: | |
101 | orl2 r8,r0 | |
102 | orl2 r9,r1 | |
103 | shlq $1,r4,r4 | |
104 | shrq $1,r8,r8 | |
105 | jneq 2b | |
106 | ||
107 | over: | |
108 | pushl 20(fp) | |
2b252132 | 109 | callf $8,_Kfnorm |
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110 | sign: |
111 | 1: bbc $0,r3,done | |
112 | orl2 $SIGNBIT,r0 | |
113 | done: ret | |
114 | ||
115 | retz: | |
116 | clrl r0 | |
117 | clrl r1 | |
118 | ret | |
119 | ||
120 | retz2: bbc $31,12(fp),z_div | |
121 | clrl r0 | |
122 | clrl r1 | |
123 | ret | |
124 | underf: | |
125 | orl2 $HFS_UNDF,*20(fp) | |
126 | ret | |
127 | z_div: | |
128 | orl2 $HFS_DIVZ,*20(fp) | |
129 | ret |