1 /****************************************************************************
2 *
3 * Realmode X86 Emulator Library
4 *
5 * Copyright (C) 1991-2004 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 "x86emui.h"
41
42 /*----------------------------- Implementation ----------------------------*/
43
44 #ifdef DEBUG
45
46 static void print_encoded_bytes (u16 s, u16 o);
47 static void print_decoded_instruction (void);
48 int parse_line (char *s, int *ps, int *n);
49
50 /* should look something like debug's output. */
X86EMU_trace_regs(void)51 void X86EMU_trace_regs (void)
52 {
53 if (DEBUG_TRACE()) {
54 if (M.x86.mode & (SYSMODE_PREFIX_DATA | SYSMODE_PREFIX_ADDR)) {
55 x86emu_dump_xregs();
56 } else {
57 x86emu_dump_regs();
58 }
59 }
60 if (DEBUG_DECODE() && ! DEBUG_DECODE_NOPRINT()) {
61 printf("%04x:%04x ",M.x86.saved_cs, M.x86.saved_ip);
62 print_encoded_bytes( M.x86.saved_cs, M.x86.saved_ip);
63 print_decoded_instruction();
64 }
65 }
66
X86EMU_trace_xregs(void)67 void X86EMU_trace_xregs (void)
68 {
69 if (DEBUG_TRACE()) {
70 x86emu_dump_xregs();
71 }
72 }
73
x86emu_just_disassemble(void)74 void x86emu_just_disassemble (void)
75 {
76 /*
77 * This routine called if the flag DEBUG_DISASSEMBLE is set kind
78 * of a hack!
79 */
80 printf("%04x:%04x ",M.x86.saved_cs, M.x86.saved_ip);
81 print_encoded_bytes( M.x86.saved_cs, M.x86.saved_ip);
82 print_decoded_instruction();
83 }
84
disassemble_forward(u16 seg,u16 off,int n)85 void disassemble_forward (u16 seg, u16 off, int n)
86 {
87 X86EMU_sysEnv tregs;
88 int i;
89 u8 op1;
90 /*
91 * hack, hack, hack. What we do is use the exact machinery set up
92 * for execution, except that now there is an additional state
93 * flag associated with the "execution", and we are using a copy
94 * of the register struct. All the major opcodes, once fully
95 * decoded, have the following two steps: TRACE_REGS(r,m);
96 * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
97 * the preprocessor. The TRACE_REGS macro expands to:
98 *
99 * if (debug&DEBUG_DISASSEMBLE)
100 * {just_disassemble(); goto EndOfInstruction;}
101 * if (debug&DEBUG_TRACE) trace_regs(r,m);
102 *
103 * ...... and at the last line of the routine.
104 *
105 * EndOfInstruction: end_instr();
106 *
107 * Up to the point where TRACE_REG is expanded, NO modifications
108 * are done to any register EXCEPT the IP register, for fetch and
109 * decoding purposes.
110 *
111 * This was done for an entirely different reason, but makes a
112 * nice way to get the system to help debug codes.
113 */
114 tregs = M;
115 tregs.x86.R_IP = off;
116 tregs.x86.R_CS = seg;
117
118 /* reset the decoding buffers */
119 tregs.x86.enc_str_pos = 0;
120 tregs.x86.enc_pos = 0;
121
122 /* turn on the "disassemble only, no execute" flag */
123 tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
124
125 /* DUMP NEXT n instructions to screen in straight_line fashion */
126 /*
127 * This looks like the regular instruction fetch stream, except
128 * that when this occurs, each fetched opcode, upon seeing the
129 * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
130 * the instruction. XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
131 * Note the use of a copy of the register structure...
132 */
133 for (i=0; i<n; i++) {
134 op1 = (*sys_rdb)(((u32)M.x86.R_CS<<4) + (M.x86.R_IP++));
135 (x86emu_optab[op1])(op1);
136 }
137 /* end major hack mode. */
138 }
139
x86emu_check_ip_access(void)140 void x86emu_check_ip_access (void)
141 {
142 /* NULL as of now */
143 }
144
x86emu_check_sp_access(void)145 void x86emu_check_sp_access (void)
146 {
147 }
148
x86emu_check_mem_access(u32 dummy)149 void x86emu_check_mem_access (u32 dummy)
150 {
151 /* check bounds, etc */
152 }
153
x86emu_check_data_access(uint dummy1,uint dummy2)154 void x86emu_check_data_access (uint dummy1, uint dummy2)
155 {
156 /* check bounds, etc */
157 }
158
x86emu_inc_decoded_inst_len(int x)159 void x86emu_inc_decoded_inst_len (int x)
160 {
161 M.x86.enc_pos += x;
162 }
163
x86emu_decode_printf(const char * x)164 void x86emu_decode_printf (const char *x)
165 {
166 strcpy(M.x86.decoded_buf+M.x86.enc_str_pos,x);
167 M.x86.enc_str_pos += strlen(x);
168 }
169
x86emu_decode_printf2(const char * x,int y)170 void x86emu_decode_printf2 (const char *x, int y)
171 {
172 char temp[100];
173 snprintf(temp, sizeof(temp), x,y);
174 strcpy(M.x86.decoded_buf+M.x86.enc_str_pos,temp);
175 M.x86.enc_str_pos += strlen(temp);
176 }
177
x86emu_end_instr(void)178 void x86emu_end_instr (void)
179 {
180 M.x86.enc_str_pos = 0;
181 M.x86.enc_pos = 0;
182 }
183
print_encoded_bytes(u16 s,u16 o)184 static void print_encoded_bytes (u16 s, u16 o)
185 {
186 int i;
187 char buf1[64];
188 for (i=0; i< M.x86.enc_pos; i++) {
189 snprintf(buf1+2*i, 64 - 2 * i, "%02x", fetch_data_byte_abs(s,o+i));
190 }
191 printf("%-20s ",buf1);
192 }
193
print_decoded_instruction(void)194 static void print_decoded_instruction (void)
195 {
196 printf("%s", M.x86.decoded_buf);
197 }
198
x86emu_print_int_vect(u16 iv)199 void x86emu_print_int_vect (u16 iv)
200 {
201 u16 seg,off;
202
203 if (iv > 256) return;
204 seg = fetch_data_word_abs(0,iv*4);
205 off = fetch_data_word_abs(0,iv*4+2);
206 printf("%04x:%04x ", seg, off);
207 }
208
X86EMU_dump_memory(u16 seg,u16 off,u32 amt)209 void X86EMU_dump_memory (u16 seg, u16 off, u32 amt)
210 {
211 u32 start = off & 0xfffffff0;
212 u32 end = (off+16) & 0xfffffff0;
213 u32 i;
214
215 while (end <= off + amt) {
216 printf("%04x:%04x ", seg, start);
217 for (i=start; i< off; i++)
218 printf(" ");
219 for ( ; i< end; i++)
220 printf("%02x ", fetch_data_byte_abs(seg,i));
221 printf("\n");
222 start = end;
223 end = start + 16;
224 }
225 }
226
x86emu_single_step(void)227 void x86emu_single_step (void)
228 {
229 #if 0
230 char s[1024];
231 int ps[10];
232 int ntok;
233 int cmd;
234 int done;
235 int segment;
236 int offset;
237 static int breakpoint;
238 static int noDecode = 1;
239
240 if (DEBUG_BREAK()) {
241 if (M.x86.saved_ip != breakpoint) {
242 return;
243 } else {
244 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
245 M.x86.debug |= DEBUG_TRACE_F;
246 M.x86.debug &= ~DEBUG_BREAK_F;
247 print_decoded_instruction ();
248 X86EMU_trace_regs();
249 }
250 }
251 done=0;
252 offset = M.x86.saved_ip;
253 while (!done) {
254 printf("-");
255 (void)fgets(s, 1023, stdin);
256 cmd = parse_line(s, ps, &ntok);
257 switch(cmd) {
258 case 'u':
259 disassemble_forward(M.x86.saved_cs,(u16)offset,10);
260 break;
261 case 'd':
262 if (ntok == 2) {
263 segment = M.x86.saved_cs;
264 offset = ps[1];
265 X86EMU_dump_memory(segment,(u16)offset,16);
266 offset += 16;
267 } else if (ntok == 3) {
268 segment = ps[1];
269 offset = ps[2];
270 X86EMU_dump_memory(segment,(u16)offset,16);
271 offset += 16;
272 } else {
273 segment = M.x86.saved_cs;
274 X86EMU_dump_memory(segment,(u16)offset,16);
275 offset += 16;
276 }
277 break;
278 case 'c':
279 M.x86.debug ^= DEBUG_TRACECALL_F;
280 break;
281 case 's':
282 M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
283 break;
284 case 'r':
285 X86EMU_trace_regs();
286 break;
287 case 'x':
288 X86EMU_trace_xregs();
289 break;
290 case 'g':
291 if (ntok == 2) {
292 breakpoint = ps[1];
293 if (noDecode) {
294 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
295 } else {
296 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
297 }
298 M.x86.debug &= ~DEBUG_TRACE_F;
299 M.x86.debug |= DEBUG_BREAK_F;
300 done = 1;
301 }
302 break;
303 case 'q':
304 M.x86.debug |= DEBUG_EXIT;
305 return;
306 case 'P':
307 noDecode = (noDecode)?0:1;
308 printf("Toggled decoding to %s\n",(noDecode)?"FALSE":"TRUE");
309 break;
310 case 't':
311 case 0:
312 done = 1;
313 break;
314 }
315 }
316 #endif
317 }
318
X86EMU_trace_on(void)319 int X86EMU_trace_on(void)
320 {
321 return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
322 }
323
X86EMU_trace_off(void)324 int X86EMU_trace_off(void)
325 {
326 return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
327 }
328
parse_line(char * s,int * ps,int * n)329 int parse_line (char *s, int *ps, int *n)
330 {
331 #if 0
332 int cmd;
333
334 *n = 0;
335 while(*s == ' ' || *s == '\t') s++;
336 ps[*n] = *s;
337 switch (*s) {
338 case '\n':
339 *n += 1;
340 return 0;
341 default:
342 cmd = *s;
343 *n += 1;
344 }
345
346 while (1) {
347 while (*s != ' ' && *s != '\t' && *s != '\n') s++;
348
349 if (*s == '\n')
350 return cmd;
351
352 while(*s == ' ' || *s == '\t') s++;
353
354 sscanf(s,"%x",&ps[*n]);
355 *n += 1;
356 }
357 #else
358 return 0;
359 #endif
360 }
361
362 #endif /* DEBUG */
363
x86emu_dump_regs(void)364 void x86emu_dump_regs (void)
365 {
366 printf("\tAX=%04x ", M.x86.R_AX );
367 printf("BX=%04x ", M.x86.R_BX );
368 printf("CX=%04x ", M.x86.R_CX );
369 printf("DX=%04x ", M.x86.R_DX );
370 printf("SP=%04x ", M.x86.R_SP );
371 printf("BP=%04x ", M.x86.R_BP );
372 printf("SI=%04x ", M.x86.R_SI );
373 printf("DI=%04x\n", M.x86.R_DI );
374 printf("\tDS=%04x ", M.x86.R_DS );
375 printf("ES=%04x ", M.x86.R_ES );
376 printf("SS=%04x ", M.x86.R_SS );
377 printf("CS=%04x ", M.x86.R_CS );
378 printf("IP=%04x ", M.x86.R_IP );
379 if (ACCESS_FLAG(F_OF)) printf("OV "); /* CHECKED... */
380 else printf("NV ");
381 if (ACCESS_FLAG(F_DF)) printf("DN ");
382 else printf("UP ");
383 if (ACCESS_FLAG(F_IF)) printf("EI ");
384 else printf("DI ");
385 if (ACCESS_FLAG(F_SF)) printf("NG ");
386 else printf("PL ");
387 if (ACCESS_FLAG(F_ZF)) printf("ZR ");
388 else printf("NZ ");
389 if (ACCESS_FLAG(F_AF)) printf("AC ");
390 else printf("NA ");
391 if (ACCESS_FLAG(F_PF)) printf("PE ");
392 else printf("PO ");
393 if (ACCESS_FLAG(F_CF)) printf("CY ");
394 else printf("NC ");
395 printf("\n");
396 }
397
x86emu_dump_xregs(void)398 void x86emu_dump_xregs (void)
399 {
400 printf("\tEAX=%08x ", M.x86.R_EAX );
401 printf("EBX=%08x ", M.x86.R_EBX );
402 printf("ECX=%08x ", M.x86.R_ECX );
403 printf("EDX=%08x\n", M.x86.R_EDX );
404 printf("\tESP=%08x ", M.x86.R_ESP );
405 printf("EBP=%08x ", M.x86.R_EBP );
406 printf("ESI=%08x ", M.x86.R_ESI );
407 printf("EDI=%08x\n", M.x86.R_EDI );
408 printf("\tDS=%04x ", M.x86.R_DS );
409 printf("ES=%04x ", M.x86.R_ES );
410 printf("SS=%04x ", M.x86.R_SS );
411 printf("CS=%04x ", M.x86.R_CS );
412 printf("EIP=%08x\n\t", M.x86.R_EIP );
413 if (ACCESS_FLAG(F_OF)) printf("OV "); /* CHECKED... */
414 else printf("NV ");
415 if (ACCESS_FLAG(F_DF)) printf("DN ");
416 else printf("UP ");
417 if (ACCESS_FLAG(F_IF)) printf("EI ");
418 else printf("DI ");
419 if (ACCESS_FLAG(F_SF)) printf("NG ");
420 else printf("PL ");
421 if (ACCESS_FLAG(F_ZF)) printf("ZR ");
422 else printf("NZ ");
423 if (ACCESS_FLAG(F_AF)) printf("AC ");
424 else printf("NA ");
425 if (ACCESS_FLAG(F_PF)) printf("PE ");
426 else printf("PO ");
427 if (ACCESS_FLAG(F_CF)) printf("CY ");
428 else printf("NC ");
429 printf("\n");
430 }
431