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1.1 root 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: *
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.
35: *
36: * @(#)Kdivd.s 7.1 (Berkeley) 12/6/90
37: */
38:
39: #include "../math/fp.h"
40: #include "../math/Kfp.h"
41: #include "../tahoe/SYS.h"
42:
43: #define HIDDEN 23 # here we count from 0 not from 1 as in fp.h
44:
45: .text
46: ENTRY(Kdivd, R9|R8|R7|R6|R5|R4|R3|R2)
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)
109: callf $8,_Kfnorm
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
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