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 #ifndef NO_SYS_HEADERS
44 #include <stdarg.h>
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 sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
180 M.x86.enc_str_pos += strlen(x);
181 }
182
183 void
x86emu_decode_printf2(const char * x,int y)184 x86emu_decode_printf2(const char *x, int y)
185 {
186 char temp[100];
187
188 snprintf(temp, sizeof(temp), x, y);
189 sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
190 M.x86.enc_str_pos += strlen(temp);
191 }
192
193 void
x86emu_end_instr(void)194 x86emu_end_instr(void)
195 {
196 M.x86.enc_str_pos = 0;
197 M.x86.enc_pos = 0;
198 }
199
200 static void
print_encoded_bytes(u16 s,u16 o)201 print_encoded_bytes(u16 s, u16 o)
202 {
203 int i;
204 char buf1[64];
205
206 for (i = 0; i < M.x86.enc_pos; i++) {
207 sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
208 }
209 printk("%-20s", buf1);
210 }
211
212 static void
print_decoded_instruction(void)213 print_decoded_instruction(void)
214 {
215 printk("%s", M.x86.decoded_buf);
216 }
217
218 void
x86emu_print_int_vect(u16 iv)219 x86emu_print_int_vect(u16 iv)
220 {
221 u16 seg, off;
222
223 if (iv > 256)
224 return;
225 seg = fetch_data_word_abs(0, iv * 4);
226 off = fetch_data_word_abs(0, iv * 4 + 2);
227 printk("%04x:%04x ", seg, off);
228 }
229
230 void
X86EMU_dump_memory(u16 seg,u16 off,u32 amt)231 X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
232 {
233 u32 start = off & 0xfffffff0;
234 u32 end = (off + 16) & 0xfffffff0;
235 u32 i;
236 u32 current;
237
238 current = start;
239 while (end <= off + amt) {
240 printk("%04x:%04x ", seg, start);
241 for (i = start; i < off; i++)
242 printk(" ");
243 for (; i < end; i++)
244 printk("%02x ", fetch_data_byte_abs(seg, i));
245 printk("\n");
246 start = end;
247 end = start + 16;
248 }
249 }
250
251 void
x86emu_single_step(void)252 x86emu_single_step(void)
253 {
254 return;
255 char s[1024];
256 int ps[10];
257 int ntok;
258 int cmd;
259 int done;
260 int segment;
261 int offset;
262 static int breakpoint;
263 static int noDecode = 1;
264
265 //char *p;
266
267 if (DEBUG_BREAK()) {
268 if (M.x86.saved_ip != breakpoint) {
269 return;
270 }
271 else {
272 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
273 M.x86.debug |= DEBUG_TRACE_F;
274 M.x86.debug &= ~DEBUG_BREAK_F;
275 print_decoded_instruction();
276 X86EMU_trace_regs();
277 }
278 }
279 done = 0;
280 offset = M.x86.saved_ip;
281 while (!done) {
282 printk("-");
283 //p = fgets(s, 1023, stdin);
284 cmd = parse_line(s, ps, &ntok);
285 switch (cmd) {
286 case 'u':
287 disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
288 break;
289 case 'd':
290 if (ntok == 2) {
291 segment = M.x86.saved_cs;
292 offset = ps[1];
293 X86EMU_dump_memory(segment, (u16) offset, 16);
294 offset += 16;
295 }
296 else if (ntok == 3) {
297 segment = ps[1];
298 offset = ps[2];
299 X86EMU_dump_memory(segment, (u16) offset, 16);
300 offset += 16;
301 }
302 else {
303 segment = M.x86.saved_cs;
304 X86EMU_dump_memory(segment, (u16) offset, 16);
305 offset += 16;
306 }
307 break;
308 case 'c':
309 M.x86.debug ^= DEBUG_TRACECALL_F;
310 break;
311 case 's':
312 M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
313 break;
314 case 'r':
315 X86EMU_trace_regs();
316 break;
317 case 'x':
318 X86EMU_trace_xregs();
319 break;
320 case 'g':
321 if (ntok == 2) {
322 breakpoint = ps[1];
323 if (noDecode) {
324 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
325 }
326 else {
327 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
328 }
329 M.x86.debug &= ~DEBUG_TRACE_F;
330 M.x86.debug |= DEBUG_BREAK_F;
331 done = 1;
332 }
333 break;
334 case 'q':
335 M.x86.debug |= DEBUG_EXIT;
336 return;
337 case 'P':
338 noDecode = (noDecode) ? 0 : 1;
339 printk("Toggled decoding to %s\n", (noDecode) ? "FALSE" : "TRUE");
340 break;
341 case 't':
342 case 0:
343 done = 1;
344 break;
345 }
346 }
347 }
348
349 int
X86EMU_trace_on(void)350 X86EMU_trace_on(void)
351 {
352 return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
353 }
354
355 int
X86EMU_trace_off(void)356 X86EMU_trace_off(void)
357 {
358 return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
359 }
360
361 static int
parse_line(char * s,int * ps,int * n)362 parse_line(char *s, int *ps, int *n)
363 {
364 int cmd;
365
366 *n = 0;
367 while (*s == ' ' || *s == '\t')
368 s++;
369 ps[*n] = *s;
370 switch (*s) {
371 case '\n':
372 *n += 1;
373 return 0;
374 default:
375 cmd = *s;
376 *n += 1;
377 }
378
379 while (1) {
380 while (*s != ' ' && *s != '\t' && *s != '\n')
381 s++;
382
383 if (*s == '\n')
384 return cmd;
385
386 while (*s == ' ' || *s == '\t')
387 s++;
388
389 //sscanf(s, "%x", &ps[*n]);
390 *n += 1;
391 }
392 }
393
394 #endif /* DEBUG */
395
396 void
x86emu_dump_regs(void)397 x86emu_dump_regs(void)
398 {
399 printk("\tAX=%04x ", M.x86.R_AX);
400 printk("BX=%04x ", M.x86.R_BX);
401 printk("CX=%04x ", M.x86.R_CX);
402 printk("DX=%04x ", M.x86.R_DX);
403 printk("SP=%04x ", M.x86.R_SP);
404 printk("BP=%04x ", M.x86.R_BP);
405 printk("SI=%04x ", M.x86.R_SI);
406 printk("DI=%04x\n", M.x86.R_DI);
407 printk("\tDS=%04x ", M.x86.R_DS);
408 printk("ES=%04x ", M.x86.R_ES);
409 printk("SS=%04x ", M.x86.R_SS);
410 printk("CS=%04x ", M.x86.R_CS);
411 printk("IP=%04x ", M.x86.R_IP);
412 if (ACCESS_FLAG(F_OF))
413 printk("OV "); /* CHECKED... */
414 else
415 printk("NV ");
416 if (ACCESS_FLAG(F_DF))
417 printk("DN ");
418 else
419 printk("UP ");
420 if (ACCESS_FLAG(F_IF))
421 printk("EI ");
422 else
423 printk("DI ");
424 if (ACCESS_FLAG(F_SF))
425 printk("NG ");
426 else
427 printk("PL ");
428 if (ACCESS_FLAG(F_ZF))
429 printk("ZR ");
430 else
431 printk("NZ ");
432 if (ACCESS_FLAG(F_AF))
433 printk("AC ");
434 else
435 printk("NA ");
436 if (ACCESS_FLAG(F_PF))
437 printk("PE ");
438 else
439 printk("PO ");
440 if (ACCESS_FLAG(F_CF))
441 printk("CY ");
442 else
443 printk("NC ");
444 printk("\n");
445 }
446
447 void
x86emu_dump_xregs(void)448 x86emu_dump_xregs(void)
449 {
450 printk("\tEAX=%08x ", M.x86.R_EAX);
451 printk("EBX=%08x ", M.x86.R_EBX);
452 printk("ECX=%08x ", M.x86.R_ECX);
453 printk("EDX=%08x \n", M.x86.R_EDX);
454 printk("\tESP=%08x ", M.x86.R_ESP);
455 printk("EBP=%08x ", M.x86.R_EBP);
456 printk("ESI=%08x ", M.x86.R_ESI);
457 printk("EDI=%08x\n", M.x86.R_EDI);
458 printk("\tDS=%04x ", M.x86.R_DS);
459 printk("ES=%04x ", M.x86.R_ES);
460 printk("SS=%04x ", M.x86.R_SS);
461 printk("CS=%04x ", M.x86.R_CS);
462 printk("EIP=%08x\n\t", M.x86.R_EIP);
463 if (ACCESS_FLAG(F_OF))
464 printk("OV "); /* CHECKED... */
465 else
466 printk("NV ");
467 if (ACCESS_FLAG(F_DF))
468 printk("DN ");
469 else
470 printk("UP ");
471 if (ACCESS_FLAG(F_IF))
472 printk("EI ");
473 else
474 printk("DI ");
475 if (ACCESS_FLAG(F_SF))
476 printk("NG ");
477 else
478 printk("PL ");
479 if (ACCESS_FLAG(F_ZF))
480 printk("ZR ");
481 else
482 printk("NZ ");
483 if (ACCESS_FLAG(F_AF))
484 printk("AC ");
485 else
486 printk("NA ");
487 if (ACCESS_FLAG(F_PF))
488 printk("PE ");
489 else
490 printk("PO ");
491 if (ACCESS_FLAG(F_CF))
492 printk("CY ");
493 else
494 printk("NC ");
495 printk("\n");
496 }
497