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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: * @(#)Kmodf.s 7.1 (Berkeley) 12/6/90
37: */
38:
39: #include "../tahoe/SYS.h"
40: #include "../math/fp.h"
41:
42: /*
43: * float Kmodf (value, iptr, hfs)
44: * float value, *iptr;
45: * int hfs;
46: *
47: * Modf returns the fractional part of "value",
48: * and stores the integer part indirectly through "iptr".
49: */
50: .text
51: ENTRY(Kmodf, R8|R7|R6|R5|R4|R3|R2)
52: /*
53: * Some initializations:
54: */
55: clrl r3
56: movl 4(fp),r0 /* fetch operand to r0. */
57: movl 8(fp),r1
58: movl 12(fp),r6 /* fetch addr of int to r6. */
59: /*
60: * get exponent
61: */
62: andl3 $EXPMASK,r0,r2 /* r2 will hold the exponent. */
63: shrl $EXPSHIFT,r2,r2
64: subl2 $BIAS,r2 /* unbias it. */
65: jleq allfrac /* it's int part is zero. */
66: cmpl r2,$56
67: jgeq allint /* it's fraction part is zero. */
68: /*
69: * get fraction
70: */
71: movl r0,r4 /* remember the original number. */
72: movl r1,r5
73: bbc $31,r0,positive /* if negative remember it. */
74: incl r3
75: positive:
76: /* clear the non fraction parts. */
77: andl2 $(0!(EXPMASK | SIGNBIT)),r0
78: /* add the hidden bit. */
79: orl2 $(0!CLEARHID),r0
80:
81: cmpl r2,$HID_POS /* see if there are bits to clear only in r0 */
82: jgtr in_r1 /* some bytes in r1 */
83: jeql onlyallr0 /* all r0 must be cleared. */
84: mnegl r2,r7 /* r7 - loop counter. */
85: movl $CLEARHID,r8 /* first bit to clear. */
86: 1:
87: andl2 r8,r0 /* clear int. bits from fraction part. */
88: shar $1,r8,r8
89: aoblss $0,r7,1b
90: 1:
91: andl2 r8,r4 /* clear frac bits for int calculation: */
92: shar $1,r8,r8
93: cmpl $0xffffffff,r8
94: jneq 1b
95: clrl r5
96: jmp norm
97:
98: onlyallr0:
99: clrl r0
100: clrl r5
101: jmp norm
102:
103: in_r1:
104: clrl r0
105: subl3 r2,$HID_POS,r7
106: movl $0x7fffffff,r8
107: 1:
108: andl2 r8,r1
109: shar $1,r8,r8
110: orl2 $0x80000000,r8
111: aoblss $0,r7,1b
112: 1:
113: andl2 r8,r5
114: shar $1,r8,r8
115: cmpl $0xffffffff,r8
116: jneq 1b
117: norm:
118: addl2 $BIAS,r2 /* fnorm expects it biased. */
119: pushl 16(fp) /* hfs */
120: callf $8,_Kfnorm /* normelize fraction part. */
121: cmpl $0,r0
122: jeql 1f
123: bbc $0,r3,1f
124: orl2 $0x80000000,r0
125: 1:
126: movl r4,(r6) /* put int part in place. */
127: movl r5,4(r6)
128: ret
129:
130: allint:
131: movl r0,(r6) /* copy the argument to the int addr. */
132: movl r1,4(r6)
133: clrl r0 /* clear the fraction part. */
134: clrl r1
135: ret
136:
137: allfrac:
138: /* the fraction is ready in r0. */
139: clrl (r6) /* zero the int part. */
140: clrl 4(r6)
141: ret
142:
143: ret_zero:
144: clrl (r6)
145: clrl 4(r6)
146: clrl r0
147: clrl r1
148: ret
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