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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
|
/*[
call.c
LOCAL CHAR SccsID[]="@(#)call.c 1.15 02/27/95";
CALL CPU Functions.
-------------------
]*/
#include <insignia.h>
#include <host_def.h>
#include <xt.h>
#include <c_main.h>
#include <c_addr.h>
#include <c_bsic.h>
#include <c_prot.h>
#include <c_seg.h>
#include <c_stack.h>
#include <c_xcptn.h>
#include <c_reg.h>
#include <call.h>
#include <c_xfer.h>
#include <c_tsksw.h>
#include <fault.h>
/*
=====================================================================
EXTERNAL ROUTINES STARTS HERE.
=====================================================================
*/
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* Process far calls. */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
CALLF
#ifdef ANSI
(
IU32 op1[2] /* offset:segment pointer */
)
#else
(op1)
IU32 op1[2];
#endif
{
IU16 new_cs; /* The destination */
IU32 new_ip;
IU32 cs_descr_addr; /* code segment descriptor address */
CPU_DESCR cs_entry; /* code segment descriptor entry */
ISM32 dest_type; /* category for destination */
IU8 count; /* call gate count (if used) */
IU32 dpl; /* new privilege level (if used) */
IU16 new_ss; /* The new stack */
IU32 new_sp;
ISM32 new_stk_sz; /* Size in bytes of new stack */
IU32 ss_descr_addr; /* stack segment descriptor address */
CPU_DESCR ss_entry; /* stack segment descriptor entry */
/* Variables used on stack transfers */
IU32 old_cs;
IU32 old_ip;
IU32 old_ss;
IU32 old_sp;
IU32 params[31];
ISM32 i;
/* get destination (correctly typed) */
new_cs = op1[1];
new_ip = op1[0];
if ( GET_PE() == 0 || GET_VM() == 1 )
{
/* Real Mode or V86 Mode */
/* must be able to push CS:(E)IP */
validate_stack_space(USE_SP, (ISM32)NR_ITEMS_2);
#ifdef TAKE_REAL_MODE_LIMIT_FAULT
/* do ip limit checking */
if ( new_ip > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLF_RM_CS_LIMIT);
#else /* TAKE_REAL_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Real Mode limit failures.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#endif /* TAKE_REAL_MODE_LIMIT_FAULT */
/* ALL SYSTEMS GO */
/* push return address */
spush16((IU32)GET_CS_SELECTOR());
spush((IU32)GET_EIP());
load_CS_cache(new_cs, (IU32)0, (CPU_DESCR *)0);
SET_EIP(new_ip);
}
else
{
/* protected mode */
/* decode and check final destination */
validate_far_dest(&new_cs, &new_ip, &cs_descr_addr, &count,
&dest_type, CALL_ID);
/* action possible types of target */
switch ( dest_type )
{
case NEW_TASK:
switch_tasks(NOT_RETURNING, NESTING, new_cs, cs_descr_addr, GET_EIP());
/* limit check new IP (now in new task) */
if ( GET_EIP() > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLF_TASK_CS_LIMIT);
break;
case SAME_LEVEL:
read_descriptor_linear(cs_descr_addr, &cs_entry);
/* stamp new selector with CPL */
SET_SELECTOR_RPL(new_cs, GET_CPL());
/* check room for return address CS:(E)IP */
validate_stack_space(USE_SP, (ISM32)NR_ITEMS_2);
/* do ip limit check */
if ( new_ip > cs_entry.limit )
GP((IU16)0, FAULT_CALLF_PM_CS_LIMIT_1);
/* ALL SYSTEMS GO */
/* push return address */
spush16((IU32)GET_CS_SELECTOR());
spush((IU32)GET_EIP());
load_CS_cache(new_cs, cs_descr_addr, &cs_entry);
SET_EIP(new_ip);
break;
default: /* MORE_PRIVILEGE(0|1|2) */
read_descriptor_linear(cs_descr_addr, &cs_entry);
dpl = dest_type;
/* stamp new selector with new CPL */
SET_SELECTOR_RPL(new_cs, dpl);
/* find out about new stack */
get_stack_selector_from_TSS(dpl, &new_ss, &new_sp);
/* check new stack selector */
validate_SS_on_stack_change(dpl, new_ss,
&ss_descr_addr, &ss_entry);
/* check room for SS:(E)SP
parameters
CS:(E)IP */
new_stk_sz = count + NR_ITEMS_4;
validate_new_stack_space(new_stk_sz, new_sp, &ss_entry, new_ss);
/* do ip limit check */
if ( new_ip > cs_entry.limit )
GP((IU16)0, FAULT_CALLF_PM_CS_LIMIT_2);
/* ALL SYSTEMS GO */
SET_CPL(dpl);
/* update code segment */
old_cs = (IU32)GET_CS_SELECTOR();
old_ip = GET_EIP();
load_CS_cache(new_cs, cs_descr_addr, &cs_entry);
SET_EIP(new_ip);
/* 'pop' params from old stack */
old_ss = (IU32)GET_SS_SELECTOR();
old_sp = GET_ESP();
for ( i = 0; i < count; i++ )
params[i] = spop();
/* update stack segment */
load_SS_cache(new_ss, ss_descr_addr, &ss_entry);
if ( GET_OPERAND_SIZE() == USE16 )
SET_SP(new_sp);
else
SET_ESP(new_sp);
/*
FORM NEW STACK, VIZ
========== ==========
old SS:SP -> | parm 1 | new SS:SP -> | old IP |
| parm 2 | | old CS |
| parm 3 | | parm 1 |
========== | parm 2 |
| parm 3 |
| old SP |
| old SS |
==========
*/
/* push old stack values */
spush16(old_ss);
spush(old_sp);
/* push back params onto new stack */
for ( i = count-1; i >= 0; i-- )
spush(params[i]);
/* push return address */
spush16(old_cs);
spush(old_ip);
break;
}
}
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* call near indirect */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
CALLN
IFN1(
IU32, offset
)
{
/* check push to stack ok */
validate_stack_space(USE_SP, (ISM32)NR_ITEMS_1);
/*
Although the 386 book says a 16-bit operand should be AND'ed
with 0x0000ffff, a 16-bit operand is never fetched with the
top bits dirty anyway, so we don't AND here.
*/
/* do ip limit check */
#ifdef TAKE_REAL_MODE_LIMIT_FAULT
if ( offset > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLN_RM_CS_LIMIT);
#else /* TAKE_REAL_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Real Mode limit failures.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#ifdef TAKE_PROT_MODE_LIMIT_FAULT
if ( GET_PE() == 1 && GET_VM() == 0 )
{
if ( offset > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLN_PM_CS_LIMIT);
}
#endif /* TAKE_PROT_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Protected Mode limit failues
* for the instructions with relative offsets, Jxx, LOOPxx, JCXZ,
* JMP rel and CALL rel, or instructions with near offsets,
* JMP near and CALL near.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#endif /* TAKE_REAL_MODE_LIMIT_FAULT */
/* all systems go */
spush((IU32)GET_EIP());
SET_EIP(offset);
}
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
/* call near relative */
/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
GLOBAL VOID
CALLR
IFN1(
IU32, rel_offset
)
{
IU32 new_dest;
/* check push to stack ok */
validate_stack_space(USE_SP, (ISM32)NR_ITEMS_1);
/* calculate and check new destination */
new_dest = GET_EIP() + rel_offset;
if ( GET_OPERAND_SIZE() == USE16 )
new_dest &= WORD_MASK;
/* do ip limit check */
#ifdef TAKE_REAL_MODE_LIMIT_FAULT
if ( new_dest > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLR_RM_CS_LIMIT);
#else /* TAKE_REAL_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Real Mode limit failures.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#ifdef TAKE_PROT_MODE_LIMIT_FAULT
if ( GET_PE() == 1 && GET_VM() == 0 )
{
if ( new_dest > GET_CS_LIMIT() )
GP((IU16)0, FAULT_CALLR_PM_CS_LIMIT);
}
#endif /* TAKE_PROT_MODE_LIMIT_FAULT */
/* The Soft486 EDL CPU does not take Protected Mode limit failues
* for the instructions with relative offsets, Jxx, LOOPxx, JCXZ,
* JMP rel and CALL rel, or instructions with near offsets,
* JMP near and CALL near.
* Since the Ccpu486 is used as a "reference" cpu we wish it
* to behave a C version of the EDL Cpu rather than as a C
* version of a i486.
*/
#endif /* TAKE_REAL_MODE_LIMIT_FAULT */
/* all systems go */
spush((IU32)GET_EIP());
SET_EIP(new_dest);
}
|
