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1da177e4 LT |
1 | /* libgcc1 routines for 68000 w/o floating-point hardware. |
2 | Copyright (C) 1994, 1996, 1997, 1998 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GNU CC. | |
5 | ||
6 | GNU CC is free software; you can redistribute it and/or modify it | |
7 | under the terms of the GNU General Public License as published by the | |
8 | Free Software Foundation; either version 2, or (at your option) any | |
9 | later version. | |
10 | ||
11 | In addition to the permissions in the GNU General Public License, the | |
12 | Free Software Foundation gives you unlimited permission to link the | |
13 | compiled version of this file with other programs, and to distribute | |
14 | those programs without any restriction coming from the use of this | |
15 | file. (The General Public License restrictions do apply in other | |
16 | respects; for example, they cover modification of the file, and | |
17 | distribution when not linked into another program.) | |
18 | ||
19 | This file is distributed in the hope that it will be useful, but | |
20 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
d6410efa | 22 | General Public License for more details. */ |
1da177e4 LT |
23 | |
24 | /* As a special exception, if you link this library with files | |
25 | compiled with GCC to produce an executable, this does not cause | |
26 | the resulting executable to be covered by the GNU General Public License. | |
27 | This exception does not however invalidate any other reasons why | |
28 | the executable file might be covered by the GNU General Public License. */ | |
29 | ||
30 | /* Use this one for any 680x0; assumes no floating point hardware. | |
31 | The trailing " '" appearing on some lines is for ANSI preprocessors. Yuk. | |
32 | Some of this code comes from MINIX, via the folks at ericsson. | |
33 | D. V. Henkel-Wallace (gumby@cygnus.com) Fete Bastille, 1992 | |
34 | */ | |
d13ffb56 | 35 | #include <asm/export.h> |
1da177e4 LT |
36 | /* These are predefined by new versions of GNU cpp. */ |
37 | ||
38 | #ifndef __USER_LABEL_PREFIX__ | |
39 | #define __USER_LABEL_PREFIX__ _ | |
40 | #endif | |
41 | ||
42 | #ifndef __REGISTER_PREFIX__ | |
43 | #define __REGISTER_PREFIX__ | |
44 | #endif | |
45 | ||
46 | #ifndef __IMMEDIATE_PREFIX__ | |
47 | #define __IMMEDIATE_PREFIX__ # | |
48 | #endif | |
49 | ||
50 | /* ANSI concatenation macros. */ | |
51 | ||
52 | #define CONCAT1(a, b) CONCAT2(a, b) | |
53 | #define CONCAT2(a, b) a ## b | |
54 | ||
55 | /* Use the right prefix for global labels. */ | |
56 | ||
57 | #define SYM(x) CONCAT1 (__USER_LABEL_PREFIX__, x) | |
58 | ||
59 | /* Use the right prefix for registers. */ | |
60 | ||
61 | #define REG(x) CONCAT1 (__REGISTER_PREFIX__, x) | |
62 | ||
63 | /* Use the right prefix for immediate values. */ | |
64 | ||
65 | #define IMM(x) CONCAT1 (__IMMEDIATE_PREFIX__, x) | |
66 | ||
67 | #define d0 REG (d0) | |
68 | #define d1 REG (d1) | |
69 | #define d2 REG (d2) | |
70 | #define d3 REG (d3) | |
71 | #define d4 REG (d4) | |
72 | #define d5 REG (d5) | |
73 | #define d6 REG (d6) | |
74 | #define d7 REG (d7) | |
75 | #define a0 REG (a0) | |
76 | #define a1 REG (a1) | |
77 | #define a2 REG (a2) | |
78 | #define a3 REG (a3) | |
79 | #define a4 REG (a4) | |
80 | #define a5 REG (a5) | |
81 | #define a6 REG (a6) | |
82 | #define fp REG (fp) | |
83 | #define sp REG (sp) | |
84 | ||
85 | .text | |
86 | .proc | |
87 | .globl SYM (__udivsi3) | |
88 | SYM (__udivsi3): | |
89 | #if !(defined(__mcf5200__) || defined(__mcoldfire__)) | |
90 | movel d2, sp@- | |
91 | movel sp@(12), d1 /* d1 = divisor */ | |
92 | movel sp@(8), d0 /* d0 = dividend */ | |
93 | ||
94 | cmpl IMM (0x10000), d1 /* divisor >= 2 ^ 16 ? */ | |
95 | jcc L3 /* then try next algorithm */ | |
96 | movel d0, d2 | |
97 | clrw d2 | |
98 | swap d2 | |
99 | divu d1, d2 /* high quotient in lower word */ | |
100 | movew d2, d0 /* save high quotient */ | |
101 | swap d0 | |
102 | movew sp@(10), d2 /* get low dividend + high rest */ | |
103 | divu d1, d2 /* low quotient */ | |
104 | movew d2, d0 | |
105 | jra L6 | |
106 | ||
107 | L3: movel d1, d2 /* use d2 as divisor backup */ | |
108 | L4: lsrl IMM (1), d1 /* shift divisor */ | |
109 | lsrl IMM (1), d0 /* shift dividend */ | |
110 | cmpl IMM (0x10000), d1 /* still divisor >= 2 ^ 16 ? */ | |
111 | jcc L4 | |
112 | divu d1, d0 /* now we have 16 bit divisor */ | |
113 | andl IMM (0xffff), d0 /* mask out divisor, ignore remainder */ | |
114 | ||
115 | /* Multiply the 16 bit tentative quotient with the 32 bit divisor. Because of | |
116 | the operand ranges, this might give a 33 bit product. If this product is | |
117 | greater than the dividend, the tentative quotient was too large. */ | |
118 | movel d2, d1 | |
119 | mulu d0, d1 /* low part, 32 bits */ | |
120 | swap d2 | |
121 | mulu d0, d2 /* high part, at most 17 bits */ | |
122 | swap d2 /* align high part with low part */ | |
123 | tstw d2 /* high part 17 bits? */ | |
124 | jne L5 /* if 17 bits, quotient was too large */ | |
125 | addl d2, d1 /* add parts */ | |
126 | jcs L5 /* if sum is 33 bits, quotient was too large */ | |
127 | cmpl sp@(8), d1 /* compare the sum with the dividend */ | |
128 | jls L6 /* if sum > dividend, quotient was too large */ | |
129 | L5: subql IMM (1), d0 /* adjust quotient */ | |
130 | ||
131 | L6: movel sp@+, d2 | |
132 | rts | |
133 | ||
134 | #else /* __mcf5200__ || __mcoldfire__ */ | |
135 | ||
136 | /* Coldfire implementation of non-restoring division algorithm from | |
137 | Hennessy & Patterson, Appendix A. */ | |
138 | link a6,IMM (-12) | |
139 | moveml d2-d4,sp@ | |
140 | movel a6@(8),d0 | |
141 | movel a6@(12),d1 | |
142 | clrl d2 | clear p | |
143 | moveq IMM (31),d4 | |
144 | L1: addl d0,d0 | shift reg pair (p,a) one bit left | |
145 | addxl d2,d2 | |
146 | movl d2,d3 | subtract b from p, store in tmp. | |
147 | subl d1,d3 | |
148 | jcs L2 | if no carry, | |
149 | bset IMM (0),d0 | set the low order bit of a to 1, | |
150 | movl d3,d2 | and store tmp in p. | |
151 | L2: subql IMM (1),d4 | |
152 | jcc L1 | |
153 | moveml sp@,d2-d4 | restore data registers | |
154 | unlk a6 | and return | |
155 | rts | |
156 | #endif /* __mcf5200__ || __mcoldfire__ */ | |
d13ffb56 | 157 | EXPORT_SYMBOL(__udivsi3) |