1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/* $OpenBSD: fpu.c,v 1.9 1997/03/12 13:37:00 briggs Exp $ */
/* $NetBSD: fpu.c,v 1.21 1996/12/16 16:17:16 scottr Exp $ */
/*-
* Copyright (c) 1996 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Gordon W. Ross.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Floating Point Unit (MC68881/882/040)
* Probe for the FPU at autoconfig time.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <machine/psl.h>
#include <machine/cpu.h>
#include <machine/frame.h>
/*
* FPU type; emulator uses FPU_NONE
*/
int fputype;
extern int *nofault;
static int fpu_match __P((struct device *, void *, void *));
static void fpu_attach __P((struct device *, struct device *, void *));
static int fpu_probe __P((void));
struct cfattach fpu_ca = {
sizeof(struct device), fpu_match, fpu_attach
};
struct cfdriver fpu_cd = {
NULL, "fpu", DV_DULL, 0
};
static int
fpu_match(parent, vcf, aux)
struct device *parent;
void *vcf;
void *aux;
{
return 1;
}
static char *fpu_descr[] = {
#ifdef FPU_EMULATE
"emulator", /* 0 */
#else
"no math support", /* 0 */
#endif
"mc68881", /* 1 */
"mc68882", /* 2 */
"mc68040", /* 3 */
"mc68060", /* 4 */
"unknown" };
static void
fpu_attach(parent, self, args)
struct device *parent;
struct device *self;
void *args;
{
char *descr;
fputype = fpu_probe();
if ((0 <= fputype) && (fputype <= 3))
descr = fpu_descr[fputype];
else
descr = "unknown type";
printf(" (%s)\n", descr);
}
static int
fpu_probe()
{
/*
* A 68881 idle frame is 28 bytes and a 68882's is 60 bytes.
* We, of course, need to have enough room for either.
*/
int fpframe[60 / sizeof(int)];
label_t faultbuf;
u_char b;
nofault = (int *) &faultbuf;
if (setjmp(&faultbuf)) {
nofault = (int *) 0;
return (FPU_NONE);
}
/*
* Synchronize FPU or cause a fault.
* This should leave the 881/882 in the IDLE state,
* state, so we can determine which we have by
* examining the size of the FP state frame
*/
__asm("fnop");
nofault = (int *) 0;
/*
* Presumably, if we're an 040 and did not take exception
* above, we have an FPU. Don't bother probing.
*/
if (mmutype == MMU_68040)
return (FPU_68040);
/*
* Presumably, this will not cause a fault--the fnop should
* have if this will. We save the state in order to get the
* size of the frame.
*/
__asm("movl %0, a0; fsave a0@" : : "a" (fpframe) : "a0" );
b = *((u_char *) fpframe + 1);
/*
* Now, restore a NULL state to reset the FPU.
*/
fpframe[0] = fpframe[1] = 0;
m68881_restore((struct fpframe *) fpframe);
/*
* The size of a 68881 IDLE frame is 0x18
* and a 68882 frame is 0x38
*/
if (b == 0x18)
return (FPU_68881);
if (b == 0x38)
return (FPU_68882);
/*
* If it's not one of the above, we have no clue what it is.
*/
return (FPU_UNKNOWN);
}
|
