1 /****************************************************************************
2 *
3 * Realmode X86 Emulator Library
4 *
5 * Copyright (C) 1996-1999 SciTech Software, Inc.
6 * Copyright (C) David Mosberger-Tang
7 * Copyright (C) 1999 Egbert Eich
8 *
9 * ========================================================================
10 *
11 * Permission to use, copy, modify, distribute, and sell this software and
12 * its documentation for any purpose is hereby granted without fee,
13 * provided that the above copyright notice appear in all copies and that
14 * both that copyright notice and this permission notice appear in
15 * supporting documentation, and that the name of the authors not be used
16 * in advertising or publicity pertaining to distribution of the software
17 * without specific, written prior permission. The authors makes no
18 * representations about the suitability of this software for any purpose.
19 * It is provided "as is" without express or implied warranty.
20 *
21 * THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
22 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
23 * EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
24 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
25 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
26 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
27 * PERFORMANCE OF THIS SOFTWARE.
28 *
29 * ========================================================================
30 *
31 * Language: ANSI C
32 * Environment: Any
33 * Developer: Kendall Bennett
34 *
35 * Description: This file contains the code to handle debugging of the
36 * emulator.
37 *
38 ****************************************************************************/
39
40 #include "x86emu/x86emui.h"
41 #include <stdio.h>
42 #include <string.h>
43 #include <stdarg.h>
44 #ifndef NO_SYS_HEADERS
45 #include <stdlib.h>
46 #endif
47
48 /*----------------------------- Implementation ----------------------------*/
49
50 #ifdef DEBUG
51
52 static void print_encoded_bytes(u16 s, u16 o);
53 static void print_decoded_instruction(void);
54 static int parse_line(char *s, int *ps, int *n);
55
56 /* should look something like debug's output. */
57 void
X86EMU_trace_regs(void)58 X86EMU_trace_regs(void)
59 {
60 if (DEBUG_TRACE()) {
61 x86emu_dump_regs();
62 }
63 if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
64 printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
65 print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
66 print_decoded_instruction();
67 }
68 }
69
70 void
X86EMU_trace_xregs(void)71 X86EMU_trace_xregs(void)
72 {
73 if (DEBUG_TRACE()) {
74 x86emu_dump_xregs();
75 }
76 }
77
78 void
x86emu_just_disassemble(void)79 x86emu_just_disassemble(void)
80 {
81 /*
82 * This routine called if the flag DEBUG_DISASSEMBLE is set kind
83 * of a hack!
84 */
85 printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
86 print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
87 print_decoded_instruction();
88 }
89
90 static void
disassemble_forward(u16 seg,u16 off,int n)91 disassemble_forward(u16 seg, u16 off, int n)
92 {
93 X86EMU_sysEnv tregs;
94 int i;
95 u8 op1;
96
97 /*
98 * hack, hack, hack. What we do is use the exact machinery set up
99 * for execution, except that now there is an additional state
100 * flag associated with the "execution", and we are using a copy
101 * of the register struct. All the major opcodes, once fully
102 * decoded, have the following two steps: TRACE_REGS(r,m);
103 * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
104 * the preprocessor. The TRACE_REGS macro expands to:
105 *
106 * if (debug&DEBUG_DISASSEMBLE)
107 * {just_disassemble(); goto EndOfInstruction;}
108 * if (debug&DEBUG_TRACE) trace_regs(r,m);
109 *
110 * ...... and at the last line of the routine.
111 *
112 * EndOfInstruction: end_instr();
113 *
114 * Up to the point where TRACE_REG is expanded, NO modifications
115 * are done to any register EXCEPT the IP register, for fetch and
116 * decoding purposes.
117 *
118 * This was done for an entirely different reason, but makes a
119 * nice way to get the system to help debug codes.
120 */
121 tregs = M;
122 tregs.x86.R_IP = off;
123 tregs.x86.R_CS = seg;
124
125 /* reset the decoding buffers */
126 tregs.x86.enc_str_pos = 0;
127 tregs.x86.enc_pos = 0;
128
129 /* turn on the "disassemble only, no execute" flag */
130 tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
131
132 /* DUMP NEXT n instructions to screen in straight_line fashion */
133 /*
134 * This looks like the regular instruction fetch stream, except
135 * that when this occurs, each fetched opcode, upon seeing the
136 * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
137 * the instruction. XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
138 * Note the use of a copy of the register structure...
139 */
140 for (i = 0; i < n; i++) {
141 op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
142 (x86emu_optab[op1]) (op1);
143 }
144 /* end major hack mode. */
145 }
146
147 void
x86emu_check_ip_access(void)148 x86emu_check_ip_access(void)
149 {
150 /* NULL as of now */
151 }
152
153 void
x86emu_check_sp_access(void)154 x86emu_check_sp_access(void)
155 {
156 }
157
158 void
x86emu_check_mem_access(u32 dummy)159 x86emu_check_mem_access(u32 dummy)
160 {
161 /* check bounds, etc */
162 }
163
164 void
x86emu_check_data_access(uint dummy1,uint dummy2)165 x86emu_check_data_access(uint dummy1, uint dummy2)
166 {
167 /* check bounds, etc */
168 }
169
170 void
x86emu_inc_decoded_inst_len(int x)171 x86emu_inc_decoded_inst_len(int x)
172 {
173 M.x86.enc_pos += x;
174 }
175
176 void
x86emu_decode_printf(const char * x,...)177 x86emu_decode_printf(const char *x, ...)
178 {
179 va_list ap;
180 char temp[100];
181
182 va_start(ap, x);
183 vsnprintf(temp, sizeof(temp), x, ap);
184 va_end(ap);
185 sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
186 M.x86.enc_str_pos += strlen(temp);
187 }
188
189 void
x86emu_end_instr(void)190 x86emu_end_instr(void)
191 {
192 M.x86.enc_str_pos = 0;
193 M.x86.enc_pos = 0;
194 }
195
196 static void
print_encoded_bytes(u16 s,u16 o)197 print_encoded_bytes(u16 s, u16 o)
198 {
199 int i;
200 char buf1[64];
201
202 for (i = 0; i < M.x86.enc_pos; i++) {
203 sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
204 }
205 printk("%-20s", buf1);
206 }
207
208 static void
print_decoded_instruction(void)209 print_decoded_instruction(void)
210 {
211 printk("%s", M.x86.decoded_buf);
212 }
213
214 void
x86emu_print_int_vect(u16 iv)215 x86emu_print_int_vect(u16 iv)
216 {
217 u16 seg, off;
218
219 if (iv > 256)
220 return;
221 seg = fetch_data_word_abs(0, iv * 4);
222 off = fetch_data_word_abs(0, iv * 4 + 2);
223 printk("%04x:%04x ", seg, off);
224 }
225
226 void
X86EMU_dump_memory(u16 seg,u16 off,u32 amt)227 X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
228 {
229 u32 start = off & 0xfffffff0;
230 u32 end = (off + 16) & 0xfffffff0;
231 u32 i;
232
233 while (end <= off + amt) {
234 printk("%04x:%04x ", seg, start);
235 for (i = start; i < off; i++)
236 printk(" ");
237 for (; i < end; i++)
238 printk("%02x ", fetch_data_byte_abs(seg, i));
239 printk("\n");
240 start = end;
241 end = start + 16;
242 }
243 }
244
245 void
x86emu_single_step(void)246 x86emu_single_step(void)
247 {
248 char s[1024];
249 int ps[10];
250 int ntok;
251 int cmd;
252 int done;
253 int segment;
254 int offset;
255 static int breakpoint;
256 static int noDecode = 1;
257
258 if (DEBUG_BREAK()) {
259 if (M.x86.saved_ip != breakpoint) {
260 return;
261 }
262 else {
263 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
264 M.x86.debug |= DEBUG_TRACE_F;
265 M.x86.debug &= ~DEBUG_BREAK_F;
266 print_decoded_instruction();
267 X86EMU_trace_regs();
268 }
269 }
270 done = 0;
271 offset = M.x86.saved_ip;
272 while (!done) {
273 printk("-");
274 (void)fgets(s, 1023, stdin);
275 cmd = parse_line(s, ps, &ntok);
276 switch (cmd) {
277 case 'u':
278 disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
279 break;
280 case 'd':
281 if (ntok == 2) {
282 segment = M.x86.saved_cs;
283 offset = ps[1];
284 X86EMU_dump_memory(segment, (u16) offset, 16);
285 offset += 16;
286 }
287 else if (ntok == 3) {
288 segment = ps[1];
289 offset = ps[2];
290 X86EMU_dump_memory(segment, (u16) offset, 16);
291 offset += 16;
292 }
293 else {
294 segment = M.x86.saved_cs;
295 X86EMU_dump_memory(segment, (u16) offset, 16);
296 offset += 16;
297 }
298 break;
299 case 'c':
300 M.x86.debug ^= DEBUG_TRACECALL_F;
301 break;
302 case 's':
303 M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
304 break;
305 case 'r':
306 X86EMU_trace_regs();
307 break;
308 case 'x':
309 X86EMU_trace_xregs();
310 break;
311 case 'g':
312 if (ntok == 2) {
313 breakpoint = ps[1];
314 if (noDecode) {
315 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
316 }
317 else {
318 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
319 }
320 M.x86.debug &= ~DEBUG_TRACE_F;
321 M.x86.debug |= DEBUG_BREAK_F;
322 done = 1;
323 }
324 break;
325 case 'q':
326 M.x86.debug |= DEBUG_EXIT;
327 return;
328 case 'P':
329 noDecode = (noDecode) ? 0 : 1;
330 printk("Toggled decoding to %s\n", (noDecode) ? "FALSE" : "TRUE");
331 break;
332 case 't':
333 case 0:
334 done = 1;
335 break;
336 }
337 }
338 }
339
340 int
X86EMU_trace_on(void)341 X86EMU_trace_on(void)
342 {
343 return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
344 }
345
346 int
X86EMU_trace_off(void)347 X86EMU_trace_off(void)
348 {
349 return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
350 }
351
352 static int
parse_line(char * s,int * ps,int * n)353 parse_line(char *s, int *ps, int *n)
354 {
355 int cmd;
356
357 *n = 0;
358 while (*s == ' ' || *s == '\t')
359 s++;
360 ps[*n] = *s;
361 switch (*s) {
362 case '\n':
363 *n += 1;
364 return 0;
365 default:
366 cmd = *s;
367 *n += 1;
368 }
369
370 while (1) {
371 while (*s != ' ' && *s != '\t' && *s != '\n')
372 s++;
373
374 if (*s == '\n')
375 return cmd;
376
377 while (*s == ' ' || *s == '\t')
378 s++;
379
380 sscanf(s, "%x", &ps[*n]);
381 *n += 1;
382 }
383 }
384
385 #endif /* DEBUG */
386
387 void
x86emu_dump_regs(void)388 x86emu_dump_regs(void)
389 {
390 printk("\tAX=%04x ", M.x86.R_AX);
391 printk("BX=%04x ", M.x86.R_BX);
392 printk("CX=%04x ", M.x86.R_CX);
393 printk("DX=%04x ", M.x86.R_DX);
394 printk("SP=%04x ", M.x86.R_SP);
395 printk("BP=%04x ", M.x86.R_BP);
396 printk("SI=%04x ", M.x86.R_SI);
397 printk("DI=%04x\n", M.x86.R_DI);
398 printk("\tDS=%04x ", M.x86.R_DS);
399 printk("ES=%04x ", M.x86.R_ES);
400 printk("SS=%04x ", M.x86.R_SS);
401 printk("CS=%04x ", M.x86.R_CS);
402 printk("IP=%04x ", M.x86.R_IP);
403 if (ACCESS_FLAG(F_OF))
404 printk("OV "); /* CHECKED... */
405 else
406 printk("NV ");
407 if (ACCESS_FLAG(F_DF))
408 printk("DN ");
409 else
410 printk("UP ");
411 if (ACCESS_FLAG(F_IF))
412 printk("EI ");
413 else
414 printk("DI ");
415 if (ACCESS_FLAG(F_SF))
416 printk("NG ");
417 else
418 printk("PL ");
419 if (ACCESS_FLAG(F_ZF))
420 printk("ZR ");
421 else
422 printk("NZ ");
423 if (ACCESS_FLAG(F_AF))
424 printk("AC ");
425 else
426 printk("NA ");
427 if (ACCESS_FLAG(F_PF))
428 printk("PE ");
429 else
430 printk("PO ");
431 if (ACCESS_FLAG(F_CF))
432 printk("CY ");
433 else
434 printk("NC ");
435 printk("\n");
436 }
437
438 void
x86emu_dump_xregs(void)439 x86emu_dump_xregs(void)
440 {
441 printk("\tEAX=%08x ", M.x86.R_EAX);
442 printk("EBX=%08x ", M.x86.R_EBX);
443 printk("ECX=%08x ", M.x86.R_ECX);
444 printk("EDX=%08x \n", M.x86.R_EDX);
445 printk("\tESP=%08x ", M.x86.R_ESP);
446 printk("EBP=%08x ", M.x86.R_EBP);
447 printk("ESI=%08x ", M.x86.R_ESI);
448 printk("EDI=%08x\n", M.x86.R_EDI);
449 printk("\tDS=%04x ", M.x86.R_DS);
450 printk("ES=%04x ", M.x86.R_ES);
451 printk("SS=%04x ", M.x86.R_SS);
452 printk("CS=%04x ", M.x86.R_CS);
453 printk("EIP=%08x\n\t", M.x86.R_EIP);
454 if (ACCESS_FLAG(F_OF))
455 printk("OV "); /* CHECKED... */
456 else
457 printk("NV ");
458 if (ACCESS_FLAG(F_DF))
459 printk("DN ");
460 else
461 printk("UP ");
462 if (ACCESS_FLAG(F_IF))
463 printk("EI ");
464 else
465 printk("DI ");
466 if (ACCESS_FLAG(F_SF))
467 printk("NG ");
468 else
469 printk("PL ");
470 if (ACCESS_FLAG(F_ZF))
471 printk("ZR ");
472 else
473 printk("NZ ");
474 if (ACCESS_FLAG(F_AF))
475 printk("AC ");
476 else
477 printk("NA ");
478 if (ACCESS_FLAG(F_PF))
479 printk("PE ");
480 else
481 printk("PO ");
482 if (ACCESS_FLAG(F_CF))
483 printk("CY ");
484 else
485 printk("NC ");
486 printk("\n");
487 }
488