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1 | /* |
2 | * Copyright (c) 1986 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 | * | |
1c15e888 C |
8 | * Redistribution and use in source and binary forms are permitted |
9 | * provided that: (1) source distributions retain this entire copyright | |
10 | * notice and comment, and (2) distributions including binaries display | |
11 | * the following acknowledgement: ``This product includes software | |
12 | * developed by the University of California, Berkeley and its contributors'' | |
13 | * in the documentation or other materials provided with the distribution | |
14 | * and in all advertising materials mentioning features or use of this | |
15 | * software. Neither the name of the University nor the names of its | |
16 | * contributors may be used to endorse or promote products derived | |
17 | * from this software without specific prior written permission. | |
18 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR | |
19 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED | |
20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. | |
1f0502d3 KB |
21 | */ |
22 | ||
23 | #if defined(SYSLIBC_SCCS) && !defined(lint) | |
1c15e888 | 24 | .asciz "@(#)addd.s 1.3 (Berkeley) 6/1/90" |
1f0502d3 | 25 | #endif /* SYSLIBC_SCCS and not lint */ |
5733b822 SL |
26 | |
27 | #include <tahoemath/fp.h> | |
28 | #include "DEFS.h" | |
29 | ||
30 | XENTRY(addd, R2|R3|R4|R5|R6|R7|R8|R9|R10) | |
31 | /* | |
32 | * see which operand has a greater exponent | |
33 | * The greater one will be fetched into r0,r1,r2,r3. | |
34 | * r0,r1 - 'pure' fraction, r2 - exponent, r3 - sign). | |
35 | * The smaller operand will be fetched into r4,r5,r6,r7. | |
36 | */ | |
37 | andl3 $EXPMASK,4(fp),r0 | |
38 | andl3 $EXPMASK,12(fp),r1 | |
39 | cmpl r0,r1 | |
40 | jgtr first_greater | |
41 | ||
42 | movl 12(fp),r0 # bigger operand to r0,r1 | |
43 | movl 16(fp),r1 | |
44 | ||
45 | movl 4(fp),r4 # smaller operand to r4,r5 | |
46 | movl 8(fp),r5 | |
47 | jmp expo | |
48 | ||
49 | first_greater: | |
50 | movl 4(fp),r0 # bigger operand to r0,r1 | |
51 | movl 8(fp),r1 | |
52 | ||
53 | movl 12(fp),r4 # smaller operand to r4,r5 | |
54 | movl 16(fp),r5 | |
55 | ||
56 | /* | |
57 | * compute exponents: | |
58 | */ | |
59 | expo: | |
60 | andl3 $EXPMASK,r0,r2 # r2 will hold the exponent. | |
61 | jeql is_res1 # check for reserved operand. | |
62 | shrl $EXPSHIFT,r2,r2 | |
63 | ||
64 | ||
65 | andl3 $EXPMASK,r4,r6 # r6 will hold the exponent. | |
66 | jeql is_res2 # check for reserved operand. | |
67 | shrl $EXPSHIFT,r6,r6 | |
68 | /* | |
69 | * compare the exponents: | |
70 | */ | |
71 | subl3 r6,r2,r8 | |
72 | jeql signs | |
73 | cmpl r8,$MAX_EXP_DIF | |
74 | jlss signs | |
75 | ret # return the bigger number. | |
76 | ||
77 | /* | |
78 | * remember the signs: | |
79 | */ | |
80 | signs: | |
81 | clrl r3 | |
82 | bbc $31,r0,sign2 # if negative remember it. | |
83 | incl r3 | |
84 | sign2: | |
85 | clrl r7 | |
86 | bbc $31,r4,frac # if negative remember it. | |
87 | incl r7 | |
88 | /* | |
89 | * compute 'pure' fraction: | |
90 | */ | |
91 | frac: | |
92 | # clear the non fraction parts. | |
93 | andl2 $(0!(EXPMASK | SIGNBIT)),r0 | |
94 | # add the hidden bit. | |
95 | orl2 $(0!CLEARHID),r0 | |
96 | # clear the non fraction parts. | |
97 | andl2 $(0!(EXPMASK | SIGNBIT)),r4 | |
98 | # add the hidden bit. | |
99 | orl2 $(0!CLEARHID),r4 | |
100 | ||
101 | /* | |
102 | * shift the smaller operand: | |
103 | */ | |
104 | shrq r8,r4,r4 | |
105 | eql_exps: | |
106 | cmpl r3,r7 | |
107 | jeql add | |
108 | bbc $0,r3,negr4r5 | |
109 | /* | |
110 | * negate the pair r0,r1: | |
111 | */ | |
112 | clrl r3 | |
113 | mcoml r1,r1 | |
114 | clrl r9 # r9 - carry flag. | |
115 | incl r1 | |
116 | bcc comr0 | |
117 | incl r9 # remember the carry. | |
118 | comr0: mcoml r0,r0 | |
119 | bbc $0,r9,add | |
120 | incl r0 | |
121 | ||
122 | /* | |
123 | * add the fractions: | |
124 | */ | |
125 | add: | |
126 | clrl r10 # to remember the sign of the result. | |
127 | addl2 r5,r1 | |
128 | adwc r4,r0 | |
129 | jgeq norm # if positive go to normelize. | |
130 | incl r10 # else remember it and negate the result. | |
131 | /* | |
132 | * negate the pair r0,r1: | |
133 | */ | |
134 | clrl r3 | |
135 | mcoml r1,r1 | |
136 | clrl r9 # r9 - carry flag. | |
137 | incl r1 | |
138 | bcc comr00 | |
139 | incl r9 # remember the carry. | |
140 | comr00: mcoml r0,r0 | |
141 | bbc $0,r9,norm | |
142 | incl r0 | |
143 | norm: callf $4,fnorm | |
144 | ||
145 | /* | |
146 | * add the sign bit | |
147 | */ | |
148 | bbs $0,r10,negative | |
149 | bbs $0,r3,negative | |
150 | ret | |
151 | negative: | |
152 | orl2 $SIGNBIT,r0 | |
153 | ret | |
154 | ||
155 | ||
156 | /* | |
157 | * negate the pair r4,r5: | |
158 | */ | |
159 | negr4r5: | |
160 | clrl r7 | |
161 | mcoml r5,r5 | |
162 | clrl r9 # r9 - carry flag. | |
163 | incl r5 | |
164 | bcc comr4 | |
165 | incl r9 # remember the carry. | |
166 | comr4: mcoml r4,r4 | |
167 | bbc $0,r9,add | |
168 | incl r4 | |
169 | jmp add | |
170 | ||
171 | ||
172 | is_res1: | |
173 | bbs $31,r0,res_op | |
174 | movl r4,r0 # return the smaller operand. | |
175 | movl r5,r1 | |
176 | ret | |
177 | ||
178 | is_res2: | |
179 | bbs $31,r4,res_op | |
180 | ret # we allready have the 'result' in r0,r1. | |
181 | ||
182 | res_op: | |
183 | callf $4,fpresop | |
184 | ret |