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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: * @(#)Kfnorm.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: .text
44: ENTRY(Kfnorm, R6|R5|R4|R3|R2)
45: # clrl r1
46: movl r0,r4 # copy to temporary.
47: jneq inr0
48: movl r1,r5
49: clrl r3 # r3 - pos of m.s.b
50: inr1: ffs r5,r6
51: incl r6
52: addl2 r6,r3
53: shrl r6,r5,r5
54: jneq inr1
55: cmpl $0,r3
56: jeql retzero
57: jmp cmpshift
58: inr0: movl $32,r3
59: inr00: ffs r4,r6
60: incl r6
61: addl2 r6,r3
62: shrl r6,r4,r4
63: jneq inr00
64:
65: cmpshift:
66: # compute the shift (r4).
67: subl3 r3,$HID_R0R1,r4
68: jlss shiftr # if less then zero we shift right.
69: shlq r4,r0,r0 # else we shift left.
70: subl2 r4,r2 # uodate exponent.
71: jleq underflow # if less then 0 (biased) it is underflow.
72: jmp combine # go to combine exponent and fraction.
73: shiftr:
74: mnegl r4,r4
75: shrq r4,r0,r0 # shift right.
76: addl2 r4,r2 # update exponent
77: cmpl r2,$256
78: jgeq overflow # check for overflow.
79: combine:
80: andl2 $CLEARHID,r0 # clear the hidden bit.
81: shal $EXPSHIFT,r2,r2 # shift the exponent to its proper place.
82: orl2 r2,r0
83: ret
84:
85: underflow:
86: clrl r0
87: orl2 $HFS_UNDF,*4(fp)
88: ret
89:
90: overflow:
91: orl2 $HFS_OVF,*4(fp)
92: ret
93: retzero:
94: clrl r0
95: clrl r1
96: ret
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